Abs 1975 single point moorings

Rules for Building and Classing
Single Point Moorings
1975
American Bureau of Shipping
Incorporated by Act of the Legislature of
the State of New York 1 862
Copyright © 1975 American Bureau of Shipping
45 Eisenhower Drive
Paramus, New Jersey 07652
Second Printing, April 1979
Third Printing, October 1981
Fourth Printing, April 1986

Foreword
These Rules have been developed in part from a background of
experience with a considerable number of single point moorings.
Because single point moorings vary widely in design, the American
Bureau of Shipping requested assistance from a number of people
expert in the design, construction and operation of single point
moorings. A Special Committee on Single Point Moorings was
formed by the Bureau to assist in the development of design criteria
and construction requirements for these structures. The scope of
these Rules covers single point mooring facilities from the manifold
at the base of the SPM to the manifold on the moored vessel,
These Rules are the result of the efforts of the Bureau’s Technical
Staff and of the Special Committee.
For the convenience of the user of the Rules for Building and
Classing Single Point Moorings the Bureau has supplied with this
volume separate copies of the latest editions of the “Buoy Mooring
Forum Hose Standards” and the “Buoy Mooring Forum Hose Guide”
through the cooperation of the Oil Companies International Marine
Forum (OCIMF).

Contents
Rules for Building and Classing Single Point Moorings
SECTION
1 Conditions of Classification
2 Definitions
3 Site Conditions
1 Design Loads
5 Structural Design
(i Mooring and Anchoring
7 Cargo Transfer System and Components
8 Safety Provisions
9 Welding
10 Initial Testing and Maintenance of Class Surveys
APPENDICES
A Administration and Technical Committees
B Bureau Offices

SECTION 1
Conditions of Classification
1.1 Class Designation
1.1.1 Single Point Moorings Built Under Survey
Single point moorings which have been built under the supervision
of the Surveyors to the Bureau to the requirements of these Rules
or to their equivalent, where approved by the Classification Commit
tee, will he classed and distinguished in the Record by the symbols
+ Al Single Point Mooring. Notations as described in 1.1.3 will be
indicated in the Record.
1.1.2 Single Point Moorings Not Built Under Survey
Single Point Moorings which have not l)een built under the super
vision of the Surveyors to the Bureau, hut which are submitted for
classification, will be subjected to a special classification survey.
Where found satisfactory, and thereafter approved by the Classifica
tion Committee, they will be classed and distinguished in the Record
by the symbols and special notations as described in 1.1.1 and 1.1.3,
but the mark + signifying the special survey during construction
will be omitted.
1.1.3 Classification Notations
Data on single point moorings will be published in the Record as
to the general geographical location of the mooring, the length
overall and deadweight of the ship it is designed to moor, the depth
of water at the site, the general types of cargo and other fluids which
the mooring is designed to handle, and any other pertinent infor
mnation.
1.3 Novel Features
Single Point Mooring units which contain novel features of design,
in respect to buoyancy, structural arrangements, machinery or
equipment, to which the provisions of these Rules are iot directly
applicable, may he classed when approved by the Classification
Committee on the basis that the Rules, insofar as applicable, have
been complied with and that special consideration has been given
to the novel features based on the best information available at the
time.
SECTION 1 Ii Conditions of Classification

L5 Submission of Site Chart
To demonstrate that navigational considerations have been taken into
account in establishing the mooring location, a site chart of the
mooring area is to be submitted in accordance with Section 3 which
shows the location of the mooring, potential navigation hazards and
existing and planned navigation aids, bottom contour elevations, the
maneuvering area, and swing circle.
1.7 Submission of Site Condition Reports
To demonstrate that site conditions have been ascertained and taken
into consideration in establishing design criteria, reports on subjects
including the following are to be submitted in accordance with
Section :3,
Environmental conditions of waves, wind, current, seiche, tide, visi
bility, temperature, and ice.
Water depth, at berth and throughout the maneuvering area bottom
soil conditions, and subsurface hazards.
1.9 Submission of Design Data
To demonstrate that the established desigi loads have been based
on the results of physical dynamic model tests in accordance with
Section 4, a report is to he submitted describing the design loads
and the techniques by which they were established, including a
description of the model testing techniques, a summary of their
results, and any calculations or formulas used in establishing the
design loads. All reports are to describe the methods and equipment
ised in obtaining the data and the qualifications of the person or
persons responsible for collecting the data and its analysis.
All test results, calculations, or formulae used in establishing the
design loads are to he submitted and will remain the property of
the Owner and will not be released without the Owner’s written
permission.
1.11 Submission of Plans
Plans showing the scantlings, arrangements and details of the princi
pal parts of the structure of each mooring to be built under survey
are to be submitted for review or approval before construction is
commenced. These plans are to clearly indicate the scantlings, joint
details and welding, or other methods of connection. Plans are gener
ally to be submitted in triplicate. In general, these plans are to
include the following where applicable.
General arrangement
Anchoring, details
Swivels, piping, and hose systems
SECTION 1 12 Conditions of CIassiflcaton

Electrical and control system
Navigational aids
Safety features
Structural plans
Compartmentation
Moormg arrangement details
1.13 Submission of Calculations
In general, where applicable, the following calculations are to be
submitted:
Structural design in accordance with Section 5
Stability calculations in accordance with Section 5
Mooring and anchorage in accordance with Section 6
Piping in accordance with Section 7
Calculations when submitted are to be footnoted indicating refer
ences.
1.15 Information Booklet
For each single point mooring (5PM) or group of single point moor
ings at a common terminal, a document is to be prepared and sub
mitted stating the criteria for which each single point mooring has
been designed, presenting information regarding the mooring area
and the components of the single point mooring, and stating recom
mendations regarding operation and maintenance of the single point
mooring facility. The docmunent is to include the following infor
mnation.
a Site chart as described in 3.3.1
b Design vessel criteria, including size (dwt), length, draft and
distance from bow to manifold.
c Environmental design criteria with various sizes of vessels, in
cluding the operating wave, wind and current.
d Design cargo transfer criteria, including type of cargo and
design maximum working pressure, temperature flow rate, and mini
mum valve closing times including the vessel’s manifold valves.
e Plans showing the general arrangement of the single point
mooring components and details of those components required to
be handled during operation or inspected during maintenance, in
cluding details of access to these components.
f Description of navigation aids and safety features.
g Recommended procedure for the mooring and unmooring of a
vessel at the SPM.
h Recommended procedure for connecting and disconnecting hose
to a tanker’s manifold.
i Recommended maintenance schedule and procedures for the
SPM facilities, including a check list of items recommended for
periodic inspection and procedures, where applicable, for adjusting
SECTION 1 3 Conditions of Classification

anchor chain tension, removal and reinstallation of hoses, adjusting
of buoyancy tanks, and replacement of the seal in the cargo swivel.
j Recommended cargo system pressure testing.
The Bureau will review and approve the Information Booklet on
the basis that it is consistent with other data submitted for classifi
cation purposes.
1.17 Fees for Classification
Fees will be charged for classification and for testing material at
prevailing rates. Estimates will be provided on request. When the
attendance of a Surveyor is required to suit the convenience of the
owners, or their representatives, outside normal working hours, an
extra fee will he charged. Expenses incurred by the Surveyor in
connection with these services will be charged in addition to the
fees.
1.19 Fees for Plan Approval
Fees, proportional to the work involved, may be charged for the
consideration of new designs of a special character submitted for
approval. Fees may also be charged for the consideration of plans
in cases where the mooring to which they relate is not constructed
under the Bureau’s survey.
1.21 Responsibility
The Bureau, being a technical society, can act only through Sur
veyors or others who are believed by it to be skilled and competent.
It is understood and agreed by all who avail themselves in any way
of the services of the Bureau that neither the Bureau nor any of
its Committees and employees will, under any circumstances what
ever, be responsible or liable in any respect for any act or omission
whether negligent or otherwise of its Surveyors, agents, employees,
Officers, or Committees, nor for any inaccuracy or omission in the
Record or any other publication of the Bureau, or in any report,
certificate, or other document issued by the Bureau, its Surveyors,
agents, employees or Committees.
1.23 Termination of Classification
The continuance of the classification of any unit is conditional upon
the Rule requirements for periodical, damage and other surveys being
duly carried out. The Committee reserves the right to reconsider,
withhold or suspend the class of any Single Point Mooring for non
compliance with these Rules, for defects reported by the Surveyor
which have not been rectified in accordance with their recommen
dations, or for non-payment of fees which are due on account of
classification and other surveys.

1.25 Materials
These Rules are intended for Single Point Moorings to he collstructe(l
of materials manufactured arid tested in accordance with the require
ments of these Rules and, where applical)le, the “Rules for Building
arid Classing Steel Vessels.” Vhere it is intended to use materials
of different processes of manufacture or of different properties, the
use of such materials and corresponding scantlings will bespeciallv
considered.
1.27 Alternate Structure Design and Equipment Arrangements
The Committee are at all times ready to consider alternate structural
design and equipment arrangements which can be shown, through
either satisfactory service experience or a systematic analysis based
on sound engineering principles, to meet the overall safety and
strength standards of the Rules. The Committee will consider special
arrangements or details of hull or equipment which can be shown
to comply with standards recognized in the country in which the
SPM is registered or built, provided they are not less effective.
1.29 Disagreement
In case of disagreement between the owners or builders and the
Surveyors regarding the material, workmanship, extent of repairs,
or application of these Rules relating to any units classed or proposed
to l)e classed by this Bureau, an appeal may be made in writing
to the Committee, who will order a special survey to be held. Should
the opinion of the Surveyor he confirmed, the expense of this. special
survey is to be paid by the party appealing.
1.31 Interpretation
Any disagreement regarding the proper interpretation of these Rules
is to be referred to the Bureau for resolution.
1.33 Effective Data of Rule Change
1.33.1 Six Month Rule
Changes to these Rules are to become effective six months from the
date on which the Technical Committee approves them. However,
the Bureau may bring into Force individual changes before that date
if necessary or appropriate.
1.33.2 Implementation of Rule Changes
In general, until the effective date, plan approval of designs will
follow prior practice unless review under the latest Rules is specifi
cally requested by the party signatory to the application for classi
fication.

SECTION 2
Definitions
2.1 Buoyancy Tanks
See 5.15.
2.3 Cargo
Any fluid transferred between the moored vessel and the pipeline
end manifold such as crude oil, petroleum product, petroleum gas,
slurry, bunkers and ballast water.
2.5 Consultant
Person or persons who through education and experience has estab
lished credentials of professionalism and expertise in the stated field.
2.7 Current, Design
See 3.7.3a.
2.9 Current, Maximum
See 3,7.3b.
2.11 Loads, Operating Anchor
See 4.1.2.
2.13 Loads, Operating Hawser
See 4.1.1.
2.15 Loads, Operating Mooring
See 4.1.
2.17 Maneuvering Area
See 3.3.3.
2.19 Seiche
See 3.7.4.
SECTION 2j1 Definitions

2.21 Single Point Mooring (SPM)
A single point mooring is an offshore berth which provides a link
between an undersea pipeline and a moored vessel for the transfer
of fluid cargoes and to which the vessel can be secured and can
weathervane during the cargo transfer as dictated by the environ
ment (wind, current, tides, etc.)
2.23 SPM, Fixed
See 5.12.
2.25 SPM, Floating
See 5.1.1.
2.27 5PM, Manned
For the application of these Rules, a manned SPM refers to a SPM
that is fitted with living accommodations and is intended to have
personnel onboard. All other SPM are considered unmanned.
2.29 Swing Circle
See 3.3.4.
2.31 Water Depth
See 3.3.5.
2.33 Wave, Maximum
See 3.7.lb.
2.35 Wave, Operating
See 3.7.la.
2.37 Wind, Maximum
See 3.7.2h.
2.39 Wind, Operating
See 3.7.2a.
2.41 API
American Petroleum Institute
SECTION 2t2 Definitions

2.43 AISC
American Institute of Steel Construction
2.45 ANSI
American National Standards Institute
2.47 ASME
American Society of Mechanical Engineers
2.49 ASTM
American Society for Testing and Materials
SECTION 213 Definitions

SECTION 3
Site Conditions
3.1 General
the provisions (if this section are intended to establish the method
at defining the location of the SPI. the environmental comlitions
which will affect operations at the 5PM and which are to be con
sidered in establishing design criteria, and bottom soil conditions
which affect the anchorage of the 5PM.
3.3 Mooring Location
3.3.1 Site Chart
A complete chart of the mooring area is to be submitted. This chart
is to show depth soundings and obstructions within the swing circle,
the maneuvering area, and. where applicable, the approach channel
from deep water or an established navigation channel. The chart
may be based on recent local charts published by government agen
cies or on recent hvdrographic surveys conducted iw a marine con
sultant. In case of charts based on hydrographic surveys, a survey
report is to be submitted describing the surveying method, equip
ment. and personnel eniploved to conduct the survey.
The exact location and water depth of the mooring base or pipe
line manifold, and each anchor point, is to he indicated on the chart.
The route of the sot ;mnarine pipeline and of all other pipelines and
cables is to be indicated on the chart. If the mooring is associated
with other SPMs in the area, or with a pumping or control platform,
these features are to be indicated on the chart..ll other features
and water use areas which may present potential navigational haz
arch are to he identified. All existing and planned navigation aids,
such as lights. buoys, and shore markers which will be used in
conjimction with the mooring are to he indicated and identified on
the chart.
3.3.2 Bottom Topography
All depths on the chart are to be referenced to the datum of local
navigational chart. The chart is to he based on depth soundings taken
at 15 in (50 ft) horizontal intervals or less.
The chart is to show bottom contours at vertical displacements
at 1.5 m (5 ft) intervals. ‘Where the bottom is very irregular, the
spacing of sounchngs is to be appropriately reduced. Where side-scan
sonar or wire drag is employed, the spacing of soundings may he
appropriately increased.
SECTION 3j1 Site Conditions

‘s.ll obstacles, such as sunken wrecks, rocks, and pinnacles. are to
he identified and their clear depths indicated. Vbere such obstacles
are encountered, wire drag at a depth beneath the required water
depth, or a sale-scan sonar survey is to he conducted throughout.
Where it is shown that water depth is far in excess of the required
water depth the survey may be appropriately modified.
3.3.3 N1aneuverin Area
lThe maneuvering area is to be indicated and captioned on the site
chart. The maneuvering area is defined as the area through which
a vessel is to maneuver in making an approach or departure from
the SPM. The shape and size of maneuvering area are to be estab
fished I used on pertinent local conditions. The radius of the maneu—
ering area about the mooring is to be at least three times the length
of the largest tanker for which the SPM is designed.
Where it can be shown that the prevailing environment (wind.
wave and current) favorabl influence the mooring nianeuver. and
that the vessel can always maneuver to and from the SPM without
danger, the maneuvering area may be appropriately modified. ‘Where
tugs will always he used to assist in mooring, the maneuvering area
may be appropriately modified. Where mooring maneuvers are to
ie made in extreme environment, the minimum radius is to be in—
reased.
Fixed obstacles such is platforms or buoys, other than the mooring,
are not to be anywhere within the maneuvering area. The route of
the submarine pipelines may be marked by a buoy at the edge of
the maneuvering area. It is suggested that no other pipelines exist
in the SPM maneuvering area.
3.3.4 Swing Circle
The swing circle is to be indicated and captioned on the site chart.
The swing circle is the area swept by the vessel as it revolves about
the mooring point. The radius of the swing circle is defined as the
sum of the horizontal displacement of the SPM from its center
position under operating hawser load and minimum tide, the hori
zontal projection of the length of the mooring line under operating
hawser load, the length over-all of the largest vessel for which the
SPl is designed, and a safety allowance of 30 m çIOO ft).
3.3.5 Water Depth at Berth
The water depth at any place within the maneuvering area is to
l)e such that no vessel which may use the berth will touch the sea
bottom or any protrusion therefrom in an’ sea condition under which
such a vessel will normally be present within the maneuvering area.
The designer may elect to specify various limiting sea conditions
applicable to various vessel sizes, in case the proposed water depth
is not sufficient to allow the presence of a vessel of the maximum
dze in the maneuvering area under the specified maximum sea condi
tions.
SEC11ON 312 Site Conditions

use (leterminatmn of the reqinred water depth is. to the extent
possible, to he based upon calculations, data from ship model tests
or full scale trials, (lesigners experience or other availal )le sources
of informalion,
The designer is to suhunt evidence to demonstrate to the satis
faction of the Bureau that in determining the re 1nired water depth
he has taken into account the effects of;
Vave height, wave period, and angle of approach to the vessel
Vessel’s dimensions and other relevant characteristics
The expected vessel’s heaving, roiling and pitching and the resulting
increase in draft at any point of the vessel’s bottom
The astronomical tides and wind set-up
The consistency of the sea bottom material or the character of any
protrusion from the sea bottom
The level of accuracy of the depth survey data.
3.5 Soils Data
3.5.1 Bottom Soil Condition
The general character of the soil on the sea floor throughout the
maneuvering area is to be indicated on the site chart. The presence
of a rock bottom or of rock outcroppings is to he clearl’ indicated.
W’here soil movements such as soil slides, excessive erosion or deposi
hon of soil, or an active fault are suspected, an analysis by a soils
consultant of the nature and degree of this hazard is to be submitted.
3.5.2 Sub-Bottom Soil Conditions
Soil data taken in the vicinity of the mooring site and an inter
pretation of such data is to be submitted by a soils consultant.
In the case of a mooring having a base, a boring or probing is
to be taken at the location of the base to the depth of any piles
or to a depth sufficient to establish the soundness of the site.
in the case of a mooring having anchor piles, borings or probings
are to l)e taken at all anchor pile locations. As an alternative, 5(11)-
bottom profile runs may be taken and correlated with at least two
borings or probings in the SPsl vicinity and an interpretation may
be niade by a soils consultant to adequately establish the soil profile
at all anchor pile locations.
In the case of a mooring having ship-type anchors or deachnen,
bottom samples are to he taken and analyzed by a soils consultant
and are to be submitted to establish the adequacy of the soil at the
site of each anchor location as a holding groimd for anchoring.
3.7 Environmental Data
3.7.1 Waves
a Operating Wave The operating wave for a vessel at the moor
ing is to be established. The operating wave is defined as the maxi
mum wave stated in terms of significant wave height the average
SECTION 313 Site Conditions

f the highest oiiethird vave heights in which a vessel will reuiain
iiOOie(l. ihe SVdS ( spectrum or iiieaii wave period correspniidiiig
to the opci ating scave height is to he stated.
I) Maxunuin Wave The iuaxniiuni wave for the design ul a siiigle
point noormg and its anchorage s ithoit a moored vessel is to he
estahlished based on not less than a I (10 ear recurrence nterval.
It is to be stated if component parts are designed for a lesser wave.
The significant wave height and the maximum peak to trough wave
height associated ith the niaxuniiin wave are to he stated. Time
mauinuiu wave is to he stited in terms of mnaximniiiii crest elevation
above mean low water and indicated if the wave is expected to be
a breaking wave. The wave spectrum or mean wave period corre
spomiding to the inaximuni wave is to he stated. The tide surge
associated with the uiaxinnun wave is to be stated.
c Wave Statistics In substantiate the above wave design criteria,
a report is to be submitted presenting wave statistics for the mooring
area. The statistics are to he based on the analysis and interpretation
of wave data by a marine consultant. The statistics are to include a
wave rose or table showing the frequency distnhiition of wave height,
period, and direction and a table or graph showing the recurrence
period of extreme storm waves, The percentage of time which the
peratuig wave height is expected to he exceeded during a year and
during the worst month or season is to he stated. The expected
(luratioli of exceedence of the operating wave height is to he stated.
It is recommended that data he ol itained from a wave recorder
operated in the general vicinity of the SPM for a period of time
adequate to establish the reliability of the wave statistics. If the site
of the wave recorder is in a different water depth or different ex
posure from the mooring site, an interpretation to transfer the data
to the mooring site is to he performed by a marine consultant.
:lternativelv, data umav he based on wave observation records br
a period of time sufficient to establish the reliability of the wave
statistics from a local shore station or from published references. The
bias of such observations against extreme storms and therefore against
extreme wave heights is to he accounted for.
The statistics for the maximum wave are to be based on wave
hindeasts for a period of time adequate to establish the reliability
of the wave statistics performed by a marine considtanit.
3.7.2 Wind
a Operating Wind The operating wind for a vessel at the moor
ing is to be established. The operating wind is defined as the maximum
wind in svhieh a vessel will remain moored stated in terms of the
fastest mile at a height of I0 m (30 ft) above the ocean surface.
b Maximum Wind The inaxiniuin wind for design of the SPNI
without a moored vessel is to be established based on not less than
a 100 year recurrence interval.
c ‘Wind Statistics A report is to he submitted presenting wind

statistics for the moorjn area. The statistics ire to i e based on the
malvsis and interpretation of wind data 1w a weather consultant.
The statistics are to include a wind rose or table showing the Ire—
1ucncv distribution of wind velocity and (lirection and a tal )le or
iraph showinti the recurrence period of extreme winds. The percent—
uie of time which the operating wind velocity is expected to he
exceeded during a year and during the worst month or season is to
he suited.
Statistics are preferably to be based on (lata from an anemometer
operated in the general vicinity of the mooring for a IWriO(l of time
adequate to establish the reliability of the wind statistics. If the site
of the anemometer is influenced by terrain or is inland, or if the
mooring site is far offshore, an interpretation to transfer the data
to the mooring site, performed by a weather or marine consultant
is to be submitted. Alternatively, the statistics may be based on wind
speed determined from synoptic weather chart pressure gradients
for a period of time sufficient to establish the reliability of the wind
statistics performed by a weather consultant. If synoptic weather
charts are not available, the statistics may be based on observations
from published references. These records are to he reviewed and
interpreted for the site by a weather consultant. The bias of such
observations against extreme storms and therefore against extreme
wind speeds is to be accounted for.
:3.7.3 Current
a Design Current The design current for a vessel at the mooring
is to be established. The design current is defined as the maximum
current not associated with a storm condition and is to be stated
in terms of velocity and depth.
b Maximum Current The maximum current for the mooring
under storm conditions without a moored vessel is to he established
based on not less than a 100 year recurrence interval and stated in
terms of velocity and depth.
c Current Statistics To substantiate the foregoing current design
criteria, a report is to be submitted presenting statistics on currents
for the mooring area. The statistics are to he based on the analysis
and interpretation of current data lw a marine consultant. The
statistics are to include a current rose or table showing the frequency
distribution of current velocity and direction. The percentage of time
which this design current is expected to be exceeded (luring a year
and during the worst month or season is to l)e stated. In the case
of an estuary site in which the current is predominantly influenced
1w tide, a table showing the influence of tide on current velocity
and direction is to be substituted. A graph or table showing the
change of current velocity with depth is to lie submitted if this
change is critical to the 5PM design. A table or graph is to be
submitted showing the recurrence period of extreme storm currents.
Statistics are preferably to l)e based on data from a current meter
or series of current meters in the vicinity of the mooring for a period

af time adequate to establish the reliability of the current statistics.If the site of the current meter is in a different water depth ordifferent exposure than the mooring site, an interpretation is to heperformed by a marine consultant to transfer the data to the mooringsite. In the case of an estuary site in which the current is predomi—nantlv influenced by tide, the statistics are to he based on data atthe mooring site and for a period of time sufficient to establish therelation between current and titles and extrapolated to extreme tidesby a marine consultant. Alternatively, statistics may he based onusirrent data from published references for a period of time sufficientto establish the reliability of the current statistics. These records areto be reviewed and interpreted for the site by a marine consultant.
3.7.4 Seiche
The location of the mooring site in relation to seiche nodal pointsis to be investigated by a marine consultant if the site is in a basinor other area known for seiche action, Seiche is defined as long periodoscillation of the water in a basin as excited by a disturbance suchas wind, waves, atmospheric pressure, or earthquake. Mooring siteslocated at or near seiche nodal points may be influenced 1w currentsnet otherwise predicted. if the mooring site is at or near a seichenodal point, currents induced by seiche are to be reflected in thedesign current and maximum current, and the influence of the periodof the current on the dynamic response of the moored vessel is tobe considered.
3.7.5 Tidal Data
Tidal data are to be based on astronomical tides and storm surge.The astronomical tidal extremes and tidal means for the mooringsite are to he established. Sufficient data are to be submitted toestablish the validity of the tide data.
Tide levels may preferably he determined from record.s of a tidegauge in the vicinity of the site or from published tide tables fora location in the vicinity of the site. If the location from which thetitle data are obtained is from a remote mooring site, a transformationof the title data to the mooring site is to be performed by a marineconsultant.
The maximum storm surge for the mooring site is to be establishedif the mooring is in a coastal or estuary location. Sufficient data areto be submitted to establish the validity of this storm surge.Maximum storm surge may preferably be determined from tiderecords taken near the location. If the location from which the tidedata are obtained is remote from the mooring site, a transformationof the tide data to the mooring site is to he performed by a marineconsultant.
Storm surge hindcats for extreme storms performed by a marineconsultant may he simhniitted.

3.7.6 Visibility
The frequency and duration of periods of reduced visibility are to
be submitted. The frequency is to be expressed in terms of percentage
of time for a year and for the worst month or season. lie duration
is to he expressed in terms of average duration of each occurrence
for the worst month or season.
Visibility may preferably he determined from observations at a
nearby location for a penod of time sufficient to establish the stability
4)1 the statistics. The principal causes of reduced visibility are to he
stated.
3.7.7 Temperatures and Ice
Where drift ice may be a hazard to a flooring or to a vessel navi
gating to or moored at a mooring or to floating hoses at a mooring,
an analysis of the nature and degree of this hazard is to be submitted.
When air temperature and precipitation, spray, or tidal action may
combine to cause substantial ice formation on the mooring, an anal
ysis of the degree to which ice may form and how this ice may affect
the performance of the mooring is to be submitted.
Stnmctmmral material, hose material and component parts which may
be affected by low temperatures are to be examined.

SECTION 4
Design Loads
4.1 Operating Mooring Loads
Operating mooring loads are the loads on the buoy and foundation
with the maximum size vessel for which the SPM is designed, or
other vessels of a smaller size if the smaller vessel is apt to unpose
higher loads in the operatIng environment as outimed in Section 3.
operating mooring loads are to he established for both the hawser
load arid the SPM anchor load. The designer is to submit operating
mooring loads based on physical dynamic model testing of the
mooring system or results of previous physical dynamic model tests
arid supporting calculations for similar SPM and environmental
conditions. It is recommended that the designer consult with the
Bureau colicerning model testing, procedures, methods and personnel
to ensure the investigation is adequate.
4.1.1 Operating Hawser Load
An operating hawser load is to be established for the mooring. The
operating hawser load is defined as the maximum load imposed on
the mooring hawser system for the maximum size vessel for which
the mooring is designed or other vessels of smaller size it the smaller
vessel is apt to impose higher loads under the influence of the Oper
ating wind, operating wave, and design current as established in
Section :3. 1)ata an(l calculations are to be submitted to establish the
validity of this operating mooring load.
The operating hawser load may be statistically determined from
model testing and analysis. The model testing and analysis on which
the operating hawser load is based is to reflect the combined effects
of wind, waves, and current on the loaded and unloaded vessel. The
model testing or analysis is to reflect the directions from which the
wind, waves, and current act. The model testing and analysis 0mm
which the operating hawser load is based is to reflect the elasticity
of the mooring system, including pretensioning of the chain.
4.1.2 Operating Anchor Load
In the case of a buoy type of mooring, an operating anchor load
is to be established for the anchor leg or legs with the vessel at the
mnooring. The operating anchor load is defined as the rmmaxinmum load
in the most highly loaded anchor leg for the maximum size vessel
for which the SPi is designed or other vessel of a smaller size, if
the smaller vessel is apt to imnpose higher loads. In the case of a
SECTION 41 Design Loads

nooring having ‘everal anchor legs of different size, an operating
anchor load is to be established for each size anchor leg. Model test
data and calculatk)HS are to be submitted to establish the validity
f the operating anchor load.
-L3 Storm Loads
Storm lua(ls are to be established for the mooring structure, each
anchor leg, and the foundation as applicable, without the vessel at
the flooring based on the maximum wind, wave, and current l)ase(l
ui mot less thaim a Bit) year recurrence interval as established in
Section 3. Model test data and calculations are to he Sul)rnitted to
uitahlish the validity of these loads.
SECTION 42 Design Loads

SECTION 5
Structural Design
5.1 General
The single point mooring structure generally consists of two types:
floating and fixed.
5.1.1 Floating Structure
The floating structure generally consists of a bno ant hull which
provides a platform for mooring attachment pointS, which supports
the anchor leg(s) that transmit mooring forces to the seabed and
which may carry cargo piping.
5.1.2 Fixed Structure
The fixed structure generally consists of a truss-like tower, a single
pile or a group of piles, fixed to the seabed which supports the
mooring system and transmits the mooring forces to the seabed.
5.3 General Design Criteria
5.3.1 Strength of Structure
The structural hull and framing members are to be of adequate size
and strength to withstand the operating and storm loads established
in Section 4. Each hawser attachment point is to he designed to
withstand an appropriate portion of the operating hawser load. Each
anchor attachment point or pile foundation is to he designed to
withstand the operating load or the storm load, whichever is greater.
Stress levels due to loads as determined from Section 4 are to he
within the values given in 5.5 and 5.7.
5.3,2 Corrosion Control
‘.“here special methods of corrosion control are provided. details of
the corrosion control system are to be submitted. Where scantlings
are determined by the requirements of 5.9.1, 5.9.2, and 5.9.3. and
effective methods of corrosion control are provided, the scantlings
may be modified as permitted by the “Rules for Building and Classing
Steel Vessels”. Where scantlings and structural design are (letermined
by the requirements of 5.5 and 5.7. or by alternative structural design
methods, and effective methods of corrosion control are not provided.
the scantlings and structural thickness arc to he suitablv increased.
SECTION 51 Structural Design

.5 Allowable Stress Levels
5.5.1 Gravity and Mooring Loading
In the case of combined gravity and mooring loadings which include
live loads other than those resulting from wind and wave forces, the
tresses are not to exceed the followint.
(f0b 0f yield strength for tensile stresses
;fi of either the local buckling or yield strength, whichever is less.
for bending stresses
57% of either the buckling or yield strength. whichever is less, for
ompressive stresses
lOb of tensile yield strength for shear stresses
5.5.2 Combined Loadings
In the case of stresses resulting from the combination of maximum
wind, gravity and mooring loadings, the stresses are not to exceed
the values listed below. However, members are not to be smaller
thui the size determined 1w 5.5.1.
0% of yield strength for tensile stresses
S0% of either the buckling or yield strength. whichever is less fur
1 )ending stresses
75% of either the lmckling or yield strength, whichever is less, for
compressive stresses
53% of tensile yield strength for shear stresses
5.5.3 Combined Axial and Bending Loadings
‘hen compressive stresses are caused by combined axial, bending
and local loadings, they are to be proportioned to satisfy the follow
ing requirements in accordance with the latest edition of the AISC
code.
/ b f F,, 13)
= computed axial compressive stress
= computed compressive bending plus local stress
allowable axial compressive stress based on overall buckling
strength. local buckling strength, or yield strength, whichever
is the smallest
F5 = allowable bending compressive stress based on local buckling
strength. or yield strength. whichever is the smaller
5.7 Stresses
5.7.1 Stnmchiral Analysis
The overall structural frame of the unit is to be stress-analyzed using
rational methods, such as finite element techniques, to determine the
resultant stresses for each member, under the loadings stipulated
herein. Analysis may be by computer; but for every structural frame
a complete and orderly analysis is to be made and submitted for
SECTION 5j2 Structural Design

review. Full c(flsi( leration is to he taken ot secondary stresses, carry—
over moments. etc.. and of three—dimensional aspects such as direc
tion ol applied forces or react ions. ( onsiderahon is to be given to
the need of anal sis for each loading condilion, including the tol—
lowing:
a liansuossion of the operating hawser load from the hawser
attachment pointI 5) to he anchor leg attachment poirlts) or to the
f)uiIdIt ion
b pp1ication of the maximum anchor load to the anchor leg
attachment point including application d appropriate wave and
ivdrosta[ic loads, in the case of a floating structure
C Application of the maximum wave. maximum wind and mnaxi—
noun current loads in the case of a fixed structure
5.7.2 Column Buckling Stresses
a Elastic Buckling Str€ss Where compression members are of
si ifficient length to buckle elastically, the following equation is to
he used.
shemi k! r > 2c-EF,
then Fe = ki r2
= elastic buckling stress
= yield stress
F modulus of elasticity
I column length
r = latest radius of gyration
K = an effective length factor to he determined as per the latest
ALSC (‘ode
b Critical Buckling Stress of a Column The critical buckling
stress of a column is to he determined from the following equation.
when KI/r ‘v22E/ Fe
then F = — F 4”E)mKLri’
Fe = compressive buckling stress
The other terms are as defined in 3.7.2a,
c Local Buckling Stresses of’ Members Local buckling stress of
members is to he investigated where appropriate.
5.7.3 Bending Stresses
a Provisions Against Local Buckling hen computing bending
stresses, the effective flange areas are to he reduced in accordance
with accepted “shear lag” and local buckling theories. Local stiffeners
are to he of sufficient size to prevent local buckling or the allowable
t ress is to he reduced proportionately.
b Consideration of Eccentric Axial Loading In the consideration
of bending stresses, elastic deflections are to he taken into account
when determining the effects of eccentricity of axial loadmg and the

resulting bending moments superimpoSed On the bending moments
oruprited for other types of loadings.
5.7.4 Shear Stresses
hen conipilting shear stresses in bulkheads, plate girder webs, or
shell plating, only the area of the svel) is to be considered effective.
In this connection the total depth of the girder may he considered
as the web depth.
5.9 Floating Structures
The hull and franses which are part of the floating structure are
to be designed in accordance with the requirements of .5.5 and 5.7.
In addition to those requirements, the scantlings of plating, stiffeners.
and beams are to he determined from the requirements of sections
5.9.1, 5.9.2, and 5.9.3. Alternatively the hull and frame design is to
be based on a systematic analysis based on sound engineering prin
ciples and accounting for the external static and dynamic pressures
imposed by the marine environment arid the internal pressure of the
contents of tanks and floodable compartments.
5.9.1 Plating
a Hull Plating The thickness of the plating is not to he less than
ol )timmned from the following ci lrmatiom.
= (sV254) + 2.54 mm
= (s v’h/460 + (). 10 in.
= thickness in mm or in.
= stiffener spacing in umni or in.
Jr = for plating, the greatest distance in in or ft from the lower edge
of the plate to the highest water level, design wave height
included, durmg the most unfavorable design situation
h Tank Plating Where the internal space is a tank, the design
head h, in association with the equation given in a, is to be taken
from the lower edge of the plate to a point located at two-thirds
of the distance from the top of the tank to the top of the overflow,
or 1.0 m :3.28 ft). whichever is greater. For tanks intended to carry
contents with a specific gravity in excess of 1.05. the design head
is to he suitahlv increased.
5.9.2 Stiffeners and Beams
Fach stiffener or beam in association with the plating to which it
is attached is to have a section modulus SM not less than that ob
tained from the following equation.
SM = ‘7.91rs12 cm3
SM = ft0041/rsl2 mi
1 unsupported length in m or ft between supports afforded by

tire shell, deck or other inciids’rs. here brackets are litted at
he shell, deck, or bulkheads which have a slope of iborit 45
degrees and a thickness indicated in Table 5.1 the length I may
be measured to a point on the bracket equal to 2o% of the length
of the bracket.
= spacing of the stiffeners in in or ft
Ii = (leek and hull stiffeners, the greatest distance, in m or ft. from
middle of I to the highest water level, design wave height
included, during the most unfavorable design situation
= for tank bulkhead .tiffeners. the value is determined from
5.9. lb.
5.9.3 Girders and Webs
a Strength Requirements ach girder or web which supports a
frame, beam, or stiffener is to have a section modulus SM not less
than obtained from the lollowing e(juat ions.
= 7.051ns12 cm’
S.I = 0.00:37h.1 in.i
= unsupported length in rn or ft between supports. Where brackets
are fitted at the shell, (leek or bulkheads which have a slope
of about -15 degrees and a thickness indicated in Table 5.1, the
length I maY be measured to a point on the bracket equal to
25% of the bracket.
S stun of half lengths in us or ft on each side of girder or web
of the frames or stiffeners supported
h = vertical distance in us or ft from the middle of s in the case
of girders and from the middle of 1 in the case of webs, to the
same heights to which h for the stiffeners is measured (see 5.9.2)
Where efficient struts are fitted connecting girders on each side of
the tanks and spaced nut over tour times the depth of the girder.
the section modulus SM for each girder may be one—half that obtained
from the above.
b Proportions Girders and webs are to have a depth not less than
of span .1 where struts are fitted. In general, the depth is not to
he less than 2.5 times the depth of the cutouts and the thickness is
not to he less than 1% of the depth plus 3 mm (0.12 in.), but need
nut exceed 11 mm 0.44 in.).
c Tripping Brackets The girders and webs are to be supported
1w tripping brackets at intervals of about :3111 10 ft) and where the
width of the unsupported face plate exceeds 152 01111 (6 in.), the
tripping brackets are to support the face plate.
5.9,4 Stability
a Intact Stability The hull is to be stable under the following
conditions.
In calm vater without mooring legs) in place
During installation

In tlie operating eiis ir inert with all flooring legs in place andret ensioned iii ider I he iperat i nt. hawser load
nder tow
h Damage Stability Che hull is to he divided by bulkheads intowatertight compart inents. Vi atertight manholes are to he providedtor access to all main floodahie roinpartnients. Ihe compartmentsare to be arranged so that with ii one coinpartnwnt flooded, thehull will not capsize or sink due to the pull of the 5 1k’nded anchorchain s) under pretension and of the uinderhnov hose nider theItaxinluin environment withtoit the vessel moored. In addition, thehuH is to he designed and sized so that with any tue anchor chainremoved. it svill not capsize dne to the pull of the remaining anchorchains, under pretension and of the nnderbuiov hose under the maxi—a nun envn’oi iment wit h nit the vessel moored.
5.9.5 Pressure lightness Testing
See 10.1.1.
5.11 Fixed Mooring System
The fixed mooring structure is to he analvzel as a space frame takinginto account the actual ermvironnmental and mnnormg loads. The analysisis to take into account operating and nuaxiumimn conditions to beanalyzed in accordance with time re(luirement.s of 5.5 and 5.7.
5.13 Additional Structural Requirements
n aopropriate tendering system is to lie designed to absorb theImpact of contact without damage to the cargo transfer system.
5.15 Buoyancy Tanks
The buoyancy tank is defined as a pressure resistant structure whichis subjected to differential pressures from snhinergence and internalpressure and which provides buoyancy to support equipment belonging to time single ponit ninoring system.
5.15.1 Pressure Test
When it is intended that the buoyancy tank is to he pressurized toequalize the external pressure. time tank will he tested to a pressure1.5 times the maximum design pressure or relief valve setting.
5.15.2 Stress Limitations
The average shell membrane stress at the test pressre is to he limitedto 9t)% of tlie ininimnm specified yield strength vliemi subject tohydrostatic testing. and to S(t% of the yield strength tinder pneumatictesting. flie conibi tation of average shell membrane stress and henri—ing stress at design operating pressure is to he limited to 50% of the

ultimate strength, or the minimum specified ie1d strength, whichever
is less. Vhen the external pressure is not compensated for by internal
pressure the stress values are also to be checked against critical buckling.
TABLE 5.1
Thickness and Flanges of Brackets
and Knees
Millimeters
I)pth
( Iii I(k1(’SS 0 zIth
Lager
Inn I’!oin [longed Flange
150 6.5
175 7.0
200 7.0 ((.5 :30
225 7.5 (3.5 :30
250 8.0 6.5 :30
275 8.0 7.0 :35
:300 S.5 7.0 :35
:325 9.0 7.0 40
:350 9.0 7.5 40
.375 9.5 7.5 45
(00 10.0 7.5 45
.425 10.0 8.0 45
450 10.5 8.0 50
475 11.0 8.0 50
.500 11.0 8.5 55
1 1 1ui’kn.
Arm I’loin Flanged
525 11.5 8.5
550 12.0 8.5
6(X) 12.5 9.0
650 13.0 9.5
7(X) 14.0 9.5
750 14.5 10.0
800 10.5
850 10.5
9(X) 11.0
950 11.5
1(8)0 11.5
1050 12.0
11(8) 12.5
1150 12.5
1200 1:3.0
Flange
33
3,3
60
65
70
1.3
$0
85
X)
90
95
1(8)
105
110
110
Inches
l)cptli
l’liickne.ss tlülth
Lunger of
rm Plain Flanged Flange
(3.0 0.26
7.5 0.28
9.0 0.30 0.26
10.5 0.32 0.26
12.0 0:34 0.28
1:3.5 (1.36 0.28
15.0 0.38 0:30
16.5 0.40 0:30
1.8.0 0.32 (1.32
19.5 0.41 0:32
21.0 0.46 0.34
l)ptli
___________
____
of Thukne,s’3 Width
Longer of
Arm [‘loin [‘longed 1 lange
22.5 046 0:34 2’/.
24.0 0.50 0.36 2’4,
1/ 25.5 0.52 0.36 2’/7
I 27.0 0.54 0.38 234
P4, 28.5 0.56 0.38 234
P4 30.0 0.58 0.40 3
33.0 0.42 34
134 :36.0 (1.44 P4,
2 39.0 0.46 :334
2 42.0 0.48 4
2’/ 450 0.50 4Y4
(‘he thickness il brackets is to he suitably increased in cases where the depth at
I hroat is less than two—thirds that of the knee.
SECTION 5j7 Structural Design

SECTION 6
Mooring and Anchoring
6.1 Anchor Points
The tYpe of anchorage for the anchor leg(s) is to be selected according
to conditions of the seabed and the maximum design anchor load.
The minimum design safety factor against the pullout of the anchor
point is to be 2. In case of a mooring employing piles, it is recom
mended that pile foundations be designed to comply with the appro
priate sections of the latest edition of API RP2A ‘Recommended
Practice for Planning, Designing and Construction, Fixed Offshore
Platforms”. A pile driving record or pile grouting record is to be taken
and submitted for each pile. The method of installation of the piles
and the equipment employed is to be included in the pile driving
record. It is recommended whenever feasible that a pull test be
applied to the anchor system. The test load is to be the mnaximunm
design load. Calculations or data from prior experience are to be
simbnmitted to support the choice of anchorage system and number
of anchor points. See also 3.5.2.
6.3 Anchor Leg(s)
Each anchor leg is to he designed with a safety factor of three against
breaking.
6.5 Anchor and Chains
:ni’hors and chains are to comply with the requirements of the
Equipmrment Section of the “Rules for Building and Classing Steel
Vessels”. Equipment designed to other standards will be specially
considered.
6.7 Mooring Lines
The mooring system between the vessel and the single point mooring
is to be designed so that the operating hawser load divided by the
number of separated mooring lines, through different fair leads,
maximum of 2. is not to be greater than .40% of the rated breaking
strength of each of the individual parts of the mooring line. For a
single mooring line with multiple parts, through a single fair lead,
the operating hawser load divided by the number of the individual
parts of the line is not to he greater than 60% of the rated breaking
strength.
SECTION 61 Mooring and Anchoring

6.9 Mooring Bearings
Bearings which carry the operating hawser load are to be designed
with a safety factor of not less than 2 without destructive yielding
of the bearing surfaces.
6.11 Structural Components
If not indicated elsewhere in these Rules, the structural and mechani
cal components which transmit the operating inoormg loads are to
he designed so the maximum stresses do not exceed 40% of the
breaking strength of the material.
SECTION 6j2 Mooring and Anchoring

SECTION 7
Cargo Transfer System
and Components
7.1 General
The provisions of this section are applicable to components of the
single point mooring (SPd) on the seaward side of the undersea
pipeline. The following conditions apply to the seaward end of the
mdersea pipelme.
a It is to he securely anchored to the sea bottom to resist forces
tine to current, waves. and forces imposed by the single point moor
ing system and undersea pipeline.
b It is reuolHluended that means for closure be provided.
Plans showing arrangement, sizes and materials of cargo transfer
system are to be submitted for approval. Types of cargo and rates
of throughput are also to be indicated.
7.3 Hoses
7.3.1 General
The length of the hose system, provision for buoyancy, spreaders
between hoses, external restraints (if required) and angle of connec
tion to the pipeline end and the SPI are to he established taking
int account.
a Maximum excursion of the 5PM both under the operating condi
tions with a moored vessel and the design conditions without a
moored vessel.
b Motion of the components of the system.
c External forces on the hose system.
d Range of specific gravity of the contents of the hose system
including the various cargoes anticipated and sea water.
The system is to he designed to avoid chaffing of underwater hose
strings when two or more strings are provided and of the hose strings
with the SI’M, anchor chains, and seabed. Checking of designs by
three dimensional scale modeling is recommended. Consideration is
to he given to providing specially’ reinforced hose in areas of maxi
mum hose flexing. Consideration is to he given to the method of
installation of the underwater hose and its removal for maintenance
or replacement. Lap joint flanges are recommended at the connection
of the hose with the pipeline end and components of the SUM 5 stem;
SECTION 71 Cargo Transfer System and Components

lifting arrangements are to he provided at the end of the floating
hose, Special hose is to be provided at the vessel end to accommodate
the bending of the hose over the vessel rail. The vessel end of the
hose is to he provided with a blind flange to avoid contamination
of the sea water. Consideration is to be given to providing swivels,
specially reinforced hose, or both, at the connection of the floatinghose with components of the 8PM sstem.
It is recommended that hose ancillary equipment, including flange
bolting and gaskets, be in accordaace with the “Bimo Mooring Forum
Hose Guide”.
7.3.2 Construction
All hose is to comply with the “Buoy Mooring Fonirn Hose Stand
ards and is to be manufactured to the Survey and Inspection of
the Bureau. Prototype hose approval in accordance with Part B ofthis standard is required.
7.3.3 Testing
Each length of hose is to be subjected to hydrostatic and vacuum
tests in accordance with requirements of Section 6, Part A of the
‘‘l3uov Mooring Forum Hose Standards”. These tests are to be wit
nessed by a Surveyor. In all cases where the design pressure of the
hose exceeds 15.8 kg/cm2 c225 psi), the hydrostatic test is to be
carried out at not less than the design pressure. Design pressure is
defined as the larger of:
a The shut-off head at the vessel’s manifold at zero flow, plus thegravity head of the contents to the part of the SPM pipe or hosein question.
h The head calculated due to surge pressure, resulting from designvalve closmg times,
Buoyancy tanks, if provided, are to be tested in accordance with
5.15.1.
7.5 Cargo Swivel and Piping
7.5.1 Cargo Swivel
Cargo swivels are to be of steel construction with flanged or welded
connections. Details of cargo swivel connecting stationary SPM)piping with rotating piping are to be submitted for approval. Suchdetails are to include plate thicknesses, nozzle locations and arrangement, seal and bearing design. and welding.
Unless mooring forces at the 8PM are isolated from the cargoswivel, the swivels are to be designed to sustain the mooring forces.
The swivel assembly is to be hydrostatically shop tested to at least1.5 times the design pressure for at least two hours with no leakageand with no unaccountable pressure changes. The swivel assemblyis to he hydrostatically shop tested to the design pressure with noleakage through two complete revolutions in each direction at a rate

of approximately ten nomites per revolution.
The swivel assembly is to be hydrostatically shop tested to the
design pressure with no leakage through four complete revolutions.
The first revolution is to be clockwise, and the final counterclockwise.
Each rotation is to he in stages of 30 degrees at a rate of approxi
mately 3() seconds per 3() degrees with a :30 second pause between
each 3() (legree rotation. For each :30 degree rotation, the breakaway
torque and the rotating torque are to be recorded. Where fluid
assembly swivel rotates in unison with mooring swivel this test is
to be conducted on the combined system.
The foregoing shop tests are to be conducted in the presence of
a Bureau Surveyor.
7.5.2 Piping
All piping for cargo transfer system mounted on the 5PM is to be
of steel preferably seamless) with welded or flanged connections.
Piping is to be not less than Schedule 40 for sizes 12 in. (ha, and
below or Schedule 30 for sizes above 12 in. dia. and is to be to ASTM
or equivalent standard. Piping is to be securely mounted on
the SPM and anchored to resist the forces resulting from internal
pressure and flow in the cargo transfer system and loads induced by
the hose system connected to it. Provision is to be made for expan
sion. Piping is to be shop tested after fabrication to a minimum pres
sure of 1.5 times the design pressure in the presence of a Surveyor.
Except as otherwise provided herein, cargo transfer piping in
stalled on manned SPMs is to complY with ANSI B31.3 (latest issue).
Except as otherwise provided herein. cargo transfer piping in
stalled on unmanned SPMs is to comply with :XSI B31 .4 (latest
issue).
7.5.3 Valves
It is recommended that a shut-off valve be provided on the SPM
for each cargo transfer line. Valves are to be of steel construction
and capable of manual operation.
7.5.4 Corrosion Protection
The cargo transfer piping, swivels, fittings and valves are to be coated
on the outside with a suitable corrosion resistant coating. This coating
will not be reqmiired for parts of corrosion resistant material.

SECTION 8
Safety Provisions
8.1 Navigation Aids
8.1.1 Obstruction Lights
Obstruction lights are to be provided as prescribed by the National
Authority having jurisdiction. If the SPM is located outside the
territorial waters of any national authority or if no lights are pre
scribed by the authority having jurisdiction, the following is to he
P’°’°cled as a minimum:
One 360 degree white light visible for five miles under an atmos
pheric transrnissivity of 1)85, flashing approximately 6 times per
minute, and arr:mged for operation at lea_st from sunset to sunrise
local time. It is recommended that the floating hoses he marked with
winker lights.
8.1.2 Fog Signal
Audible log signals are to be provided if prescribed by the National
Authority having jurisdiction.
8.1.3 Radar Reflector
A radar reflector is to he provided if prescribed by the National
Authority having jurisdiction.
8.3 Safety Features
8.3.1 Life Saving Requirements—Manned SPM
Manned 5PM stnictures are to comply with the provisions of Appen
dix B of the “Rules for Building and Classing Offshore Mobile Drill
ing Unit” as applicable considering the number of personnel.
8.3.2 Life Saving Requirements—Unmanned SPM
It is recommended that SPMs which are unmanned he equipped
where practical with at least one lifebuov with attached self-igniting
light and buoyant lifeline. Means are to be provided for the attach
ment of safety lines in all work areas. Gratings, ladders, and handrails
are to be provided as required for safe access to operating equipment.
8.:3.3 Fire Fighting Equipment—Manned 8PM
Manned SPM structures are to comply with the provisions of the
SECTION 8 1 Safety Provisions

‘Rules for Building and Classing Offshore Mobile i)rifiing Units”
Section 15) as applicable considering the number of personnel.
8.3.4 Fire Fighting Equipment—Unmanned 5PM
here flammable fluids are present it is recommended that SPMs
which are unmanned be equipped where practical with at least one
9 liter 2 U.S. gallons) foam or equivalent type B portable fire
extinguisher 15 lb carbon dioxide or 10 lb dry chemical).
8.5 Electrical Equipment
8.5.1 Manned SPMs
The electrical installation on manned SPMs is to comply with the
applicable provisions of the “Rules for Building and Classing Offshore
Mobile Drilling Units” (Section 14).
8.5.2 Unmanned SPMs
.ll electrical equipment for unmanned SPMs is to be explosion—proof
or watertight or 1)0th. as applicable.
8.7 Identification Marks
A name or number is to be assigned to each single point mooring
and is to conform to requirements of the ational Authority having
jurisdiction. This name or number is to be permanently displayed
on the stnictitre and will be entered in the Record. Draft marks are
to he permanently marked in at least two places.
8.9 Bilge Pumping
All tanks and major void compartments are to have means for sound
ing and pumping out.
SEC’T1ON 812 Safety Provisions

SECTION 9
Welding
9.1 General
9.1.1 Hull Welding
Welding in the construction of Single Point Moorings is to comply
with the requirements of this section, unless specially approved
otherwise. In all instances welding procedures and filler metals are
to be applied which will produce sound welds that have strength
and toughness comparable to that of the base material,
9.1.2 Plans and Specifications
The plans submitted are to indicate clearly the extent to which
welding is proposed to be used in the principal parts of the structure.
The welding process, filler metal and joint design are to be shown
on the detail drawings or in separate specifications submitted for
approval which should distinguish between manual and automatic
welding. The builders are to prepare an file with the Surveyors a
planned procedure to be followed in the erection and welding of
the important structural members.
9.1.3 Workmanship and Supervision
The Surveyors are to satisfy themselves that all welders and welding
operators to be employed in the construction of SPMs to be classed
are properly qualified and are experienced in the type of work pro
posed and in the proper use of welding processes and procedures
to be followed. The Surveyors are to be satisfied as to the employ
ment of a sufficient number of skilled supervisors to ensure a
thorough supervision and control of all welding operations.
9.1.4 Welding Procedures
Procedures for the welding of all joints are to be established before
construction for the welding processes, types of electrodes, edge
preparations, welding techniques and positions proposed (see Section
30 of the “Rules for Buildings and Classing Steel Vessels”). Details
of proposed welding procedures and sequences may be required to
he submitted for review depending on the intended application.
9.3 Preparation for Welding
9.3.1 Edge Preparation and Fitting
The edge preparation is to be accurate and uniform and the parts
SECTION 911 Welding

to he welded are to be fitted in accordance with the approved joint
detail. ll means adopted for correcting improper fitting are to he
tc the satisfaction of the Snrveyors. Vhere excessive root openings
are encountered, for butt weld connections, weld build op of the
plate edges may be allowed before welding the plates together pro
vided such build up is carried out to the satisfaction of the Surveyor.
L’nless specially approved otherwise, such build op of each plate
edge, where permitted, should not exceed 0.5t or 12.5 non 0.3 mi
whichever is lesser, where t is the thickness of the thinner plate being
welded. Where sections to be joined differ in thickness and have
an offset on any side of more than 3 mm (1/s
in.), a transition having
a length not less than three times the offset is to he provided. The
transition may be formed 1w tapering the thicker plate or 1w specify—
ing a weld joint design which will provide the required transition.
9.:3.2 Alignment
Means are to he provided for maintaining the parts to be welded
in correct position and alignment during the welding operation. In
general, strong hacks or other appliances used for this purpose are
to be so arranged as to allow for expansion and contraction during
production welding. The removal of such items is to l)e carried out
to the satisfaction of the Surveyors.
9.3.3 Cleanliness
All surfaces to be welded are to be free from moisture, grease, loose
mill scale, excessive rust or paint. Primer coatings of ordinary thick
nesses, thin coatings of linseed oil or equivalent coatings may he used
provided it is demonstrated that their use has no adverse effect in
the production of satisfactory welds. Slag and scale are to be removed
not only from the edges to be welded but also from each pass or
layer before the deposition of subsequent passes or layers. Weld joints
prepared by arc-air gouging may require additional preparation by
grinding or chipping and wire brushing prior to welding to minimize
the possibility of excessive carbon on the surfaces. Compliance with
these cleanliness requirements is of prime importance in the welding
of higher-strength steels especially those which are quenched and
tempered.
9.3.4 Tack Welds
Tack welds of consistent good quality, made with the same grade
of filler metal as intended for production welding and deposited in
such a manner as not to interfere with the completion of the final
weld, need not be removed provided they are found upon examina
tion to be thoroughly clean and free from cracks or other defects.
Preheat may be necessary prior to tack welding when the materials
to be joined are highly restrained. Special consideration is to be given
to use the same preheat as specified in the welding procedure when
tack welding higher-strength steels, particularly those materials
which are quenched and tempered. These same precautions are to
be followed when making any permanent welded markings.
SECTION 9j2 Welding

9.:3,5 Run-on and Run-off Tabs
Vhen used, run—on and run—off tabs are to be designed to minimize
the possibility of high—stress concentrations and base—metal and weld—
metal (racking.
9.5 Production Welding
9.5.1 Environment
Proper precautions are to he taken to insure that all welding is (lone
under conditjons where the welding site is protected against the
deleterious effects of moisture, wind and severe cold.
9.5.2 Sequence
Welding is to be planned to progress symmetrically so that shrinkage
on both sides of the structure will be equalized. The ends of frames
and stiffeners should he left unattached to the plating at the sub—
assembly stage until connecting welds are macic in the intersecting
sstems of plating, framing and stilfeners at the erection stage. Welds
are not to be carried across an unwelded joint or beyond an unwelded
joint which terminates at the joint being welded unless specially
approved.
9.5.3 Preheat
l’he use of preheat is to be considered when welding higher-strength
steels, materials of thick cross section, materials subject to high
restraint, and when wel(ling is performed under high humidity condi
tions or when the temperature of the steel is below 0 C (32 F). The
control of interpass temperature is to be specially considered when
welding quenched and tempered higher-strength steels. When pre
heat is used, the temperature is to be in accordance with the accepted
procedure and to the satisfaction of the Surveyor.
9.5.4 Low-hydrogen Electrodes or Welding Processes
The use of low-hydrogen electrodes or welding processes is recoin
mended for welding all higher-strength steel and may also be con
siderecl for ordinary-strength steel welciments subject to high re
straint. When using low-hydrogen electrodes or processes, proper
precautions are to be taken to ensure that the electrodes, fluxes and
gases used for welding are clean and dry.
9.5.5 Back Gouging
Chipping, grinding, arc-air gouging or other suitable methods are to
be employed at the root or underside of the weld to obtain sound
metal before applying subsequent beads for all frill-penetration welds.
When arc-air gouging is employed, a selected technique is to be used
so that carbon buildup and burning of the weld or base metal is
minimized. Quenched and tempered steels are not to be flame gouged.
SECTION 9{3 Welding

9.5.6 Peening
The use of peening is not recommended for single-pass welds and
the root or cover passes on imiltipass welds. Peening, when used to
correct distortion or to reduce residual stresses, is to be effected
immediately after depositing and cleaning each weld pass.
9.5.7 Fairing and Flame Shrinking
Fairing by heating or flame shrinking and other methods of correct
ing distortion or defective workmanship in fabrication of main
strength members and other plating which may be subject to high
stresses is to he carried out only with the express approval of the
Surveyors. These corrective measures are to he kept to an absolute
minimum when higher-strength steels are involved, due to high local
stresses and the possible (legradation of the mechanical properties
of the base material.
9.5.8 Weld Soundness and Surface Appearance
Finished welding is to be sound and thoroughly fused throughout
its cross section and to the base material. Production welds are to
be crack free and reasonably free from other injurious defects such
as lack of fusion or penetration, slag inclusions and porosity. The
surfaces of welds are to be visually inspected and are to be regular
and uniform with a minimum amount of reinforcement and reason
ably free from undercut and overlap.
9.5.9 Inspection of Welds
Inspection of welded joints in important locations is to be carried
out preferably by established nondestnactive test methods such as
radiographic, ultrasonic, magnetic-particle or dye-penetrant inspec
tion, The Bureau’s separately issued Rules for Nondestructive Inspec
tion of Hull Welds is to be used in evaluating radiographs for hull
structure and related welds. Radiographic or ultrasonic inspection
or both is to be used when the overall soundness of the weld cross
section is to be evaluated. Magnetic-particle or dye-penetrant in
spection or both is to be used when investigating the outer surface
of welds or may be used as a check of intermediate weld passes such
as root passes and also to check back chipped, ground or gouged
joints prior to depositing subsequent passes. Some steels, especially
higher-strength steels, exhibit a tendency to delayed cracking. When
welding these materials, consideration is to be given to delaying the
final nondestructive testing to accommodate occurrence and detec
tion of such defects. Weld run-on or run-off tabs may be used where
practical and be sectioned for examination. The practice of taking
weld plugs or samples by machining or cutting from the welded
structure is not recommended and is to be used only in the absence
of other suitable inspection methods. When such weld plugs or
samples are removed from the welded structure, the holes or cavities
thus formed are to be properly prepared and welded, using a suitable
welding procedure as established for the original joint.
SECTION 914 Welding

9.5.I() Repair Welding
Defective welds and other injurious defects, as (letermined by visual
inspection, nondestructive test methods, or leakage mder hydrostatic
tests. are to be excavated in way of the defects to sound metal and
corrected by rewelding, using a suitable repair welding procedure
to be consistent with the material being welded. Removal by rinding
of minor surlace imperfections such as scars, tack welds and arc
strikes may be permitted at the discretion of the attending Surveyor.
Special precautions, such as the use of both preheat and low—
hydrogen electrodes, are to be considered when repairing weld.s in
higher-strength steel, materials of thick cross section or materials
subject to high restraint.
9.7 Butt Welds
9.7.1 Manual Welding Using Stick Electrodes
Manual welding using stick electrodes may be ordinarily employed
for butt welds in plating not exceeding 6.5 mm /4 in.) iii thickness
without beveling the abutting plate edges. Plates exceeding 6.5 mm
(1/ ffl,) are to he prepared for welding by similarly beveling the edges
of both plates from one or both sides to form a single—Vee or double
Vee butt joint with an included angle of 6O. The root face or land
is not to exceed 3 mum in.) in depth and the root opening or
gap between the plates is not to be less than 1.5 mm in.) nor
more than 5 mm in.) except in the ease of single-Vee joints
welded in the flat position where tight fits may be used. In all ca.ses
unsound weld metal at the root on the reverse side of the weld is
to be removed to sound metal by an approved method before apply
ing subsequent weld passes. Where welding is to be deposited from
one side only, using ordinary techniques, backing is to be provided
and the plates are to be beveled to an included angle of 450
and
spaced so as to leave a gap at the root of 6.5 mm (Y in.). Other
included angles and root gaps or combinations thereof will be
specially considered. The hacking bar is to he fitted so that a mini
mown spacing exists between the backing bar and the plates to be
joined. Splices in back-tip bars are to be welded with full-penetration
welds. When it is intended to prevent the root of a butt weld in
way of a riveted seam lap from fusing to the other plate, separation
may be affected by a steel shim; the u.se of copper for this purpose
is not recommended.
9.7.2 Submerged-arc Welding
Submerged-arc welding, using wire-flux combinations for butt welds
in plating not exceeding 16 mm (% in.) in thickness, may be ordinar
ily employed without beveling the abutting plate edges. Plates ex
ceeding 16 mm in. are normally to be prepared for welding by
similarly beveling edges of both plates from one or both sides to
form a single- or double-Vee butt joint with an included angle of
6O. The root or land is not to exceed 6.5 mm (4 in.) in depth.
SECTION 95 Welding

Where the metal is to he deposited from one side OnlY, using ordmarv
welding techniqnes. hacking is to he provided and the plates are
to he beveled to an included angle of 300 and spaced so as to leave
s g ip at the root of 6 5 mm (u1 ln > [olnt designs and dct uls difici ing
from the foregoing are to be submitted and will be specially con
sidered in accordance with good welding practice and service cx
perielice.
9.7.3 Gas Metal-arc Welding
lanual semiautomatic or machine automatic gas metal-arc welding
using wire—gas combinations and associated processes. such as weld
ing with flux cored wires, may be ordinarily employed utilizing the
conditions as specified in 9.7.1. Variations of root openings or gap,
size of weld land and the included joint angle may he permitted,
consistent with good welding practice and a demonstration of satis—
factory procedure tests at the fabricator’s plant.
9.7.4 Special Welding Techniques
Special welding techniques employing any of the basic welding
processes mentioned in 9.7. 1 through . 7:3 will be specially con—
sidered, depending upon the extent of the variation from the gener
ally accepted technique. Such special techniques include one—side
welding, narrow-gap welding, tandem-arc welding, open-arc welding
and consumable-nozzle electroslag welding. The use of gas tungsten
arc welding will alsc be subject to special consideration, depending
upon the application and whether the process is used manually or
am itomatically.
9.9 Fillet Welds
9.9.1 General
‘l’he actual sizes of fillet weld.s are subject to approval in each mdi
vidual case, and are to be indicated on detail drawings or on a
separate welding schedule. Frames, beams, bulkhead stiffeners, floors
and intercostals, etc. are to have at least the disposition and sizes
of intermittent or continuous fillet welds as required by Table 9.1.
Vhere it is desirable to substitute continuous welding for inter
mittent welding as given in Table 9.1, a reduction from the required
size of fillet may be allowed if equivalent strength is provided. It
may he required that special precautions, such as the use of preheat
or low-hydrogen-type electrodes or processes, he employed where
small fillets are used for attachment to heavy plates. Fillet welds
may be made by an approved manual or automatic process. Where
automatic double continuous fillet welding is provided, a reduction
in fillet size of 1.5 mm (1/
in.) will he permitted provided that the
specified size of fillet in Table 9.1 is 6.5 mm Y in.) or greater, the
gap between members does not exceed 1.0 mm 0.04 in.) and the
penetration at the root is at least L5 mm (‘/16 in.) into the member
being attached. This reduction does not apply to slab longitudinals.
SEC11ON 9j6 Welding

9.9.2 Tee Joints
Tee joints are to be formed by either continuous or intermittent fillet
welds oii each side, as required by 9.9.3 and 9.9.4 except where
full-penetration welds may be required to develop the effectiveness
of continuous longitudinal members. In general, the required size
and spacing of the fillets is to be determined by the thickness of
the stem of the tee or the plate to which it is joined, whichever
is the lesser. Where the opening betweeti members exceeds 1.5 mm
(‘,4 in.) and is not greater than 5 mm in.), the size of the fillets
is to he increased by the amount of the opening. Spacing between
plates forming tee joints is not to exceed 5 mm (3i in.).
9.9.3 Tee-type End Connections
Tee type end connections where fillet welds are used are to have
continuous welds on each side. In general the sizes of the welds,
iv, are not to be less than times the thickness of the member being
attached, but in special cases where heavy members are attached
to relatively light plating, the sizes may be modified. In certain cases
only the webs of girders, beams and stiffeners need be attached. In
such cases it is recommended that the unattached face plates or
flanges be cut back.
9.9.4 Tee Joints at Boundary Connections
Tee joints at boundary connections of bulkheads, decks, inner hot-
turns, etc. are to have continuous welding on both sides where the
thinner of the plates is 12.5 mm (% in.) thick or greater. In general
the size of the welds iv is to be such that the two together are
not less than the thickness of the thinner plate plus 1.5 mm (16 iii.).
Where the thickness of the thinner plate is less than 12.5 mm (1/, in.),
the attachment may be made by a continuous weld on one side
1.5 mm (‘ in.) less than the thickness of the thinner plate with
intermittent welding on the opposite side of the size required by
Table 9,1 for stiffeners to deep tank bulkheads, except in way of
tanks where equivalent continuous welds are to be used.
9.9.5 Lapped Joints
Lapped joints are generally to have overlaps of not less width than
twice the thinner plate thickness plus 25 mm (1 in.). Both e(lges of
an overlap joint are to have fillet welds, which may be continuous
or intermittent and of the sizes tv as required by 9.9.6 and 9.9.7.
9.9.6 Overlapped End Connections
Overlapped end connections of longitudinal strength members are
to have continuous fillet welds on both edges each equal in size, iv,
to the thickness of the thinner of the two plates joined. All other
overlapped end connections are to have continuous welds on each
edge of sizes w such that the sum of the two is not less than 1%
times the thickness of the thinner plate.
SECTION 9j7 Welding

9.9.7 Overlapped Seams
Overlapped seams are to have welds on both edges of the sizes
required by 9.9.4 for tee connections at boundaries.
9.9.8 Plug Welds or Slot Welds
Plug welds or slot welds may be specially approved for particular
applications. Vhere used in the body of doublers and similar loca
tions, such welds may be spaced about :300 mm (12 in.) between
centers in 1)0th directions.
9.11 Alternates
The foregoing are considered minimum requirements for electric-arc
welding in hull construction, but alternate methods, arrangements
and details will be considered for approval.
9.13 Welding of Piping
See Section :30. Part II. of the “Rules for Building and Classing of
Steel Vessels”, ANSI B 31.1 or ANSI B 31.4 as applicable for welding
procedures and details of piping and machinery components.
9.15 Welding Procedures
See Section 30, Part III. of the “Rules for Building and Classing
of Steel Vessels” for the procedure to be followed in obtaining the
approval of the Bureau of electrodes and welding procedure for
qualifying welders and for demonstrating satisfactory workmanship.
SECTION 98 Welding

TABLE 9.1
W&d Sizes and Spacing
Vhere beams, stitleners, frames. etc., are intermittently welded and pass
through slotted girders. shelves or stringers, there is to be a pair of matched
intermittent welds on each side of each such intersection and the beams.
stilfeners and frames are to be efficiently attached to the girders, shelves
and stringers.
Where automatic double continuous fillet welding is provided, a reduction
in fillet size of 1.5 mm in. will be permitted provided that the specified
size of fillet is 6.5 miii I/ in.) or greater, the gap between the members
does not exceed 1.0 mm 0.04 in,) and the penetration at the root is at
least 1.5 mum I’ in. nito the roeniher being attached. This reduction does
not apply for slab longitndinals.
lfnbracketed stiffeners of shell, watertight and oiltight bulkheads are to
have double continuous welds for one—tenth of their length at each end.
Lubracketed stiffeners of nontight structural bulkheads, are to have a pair
of matched intermittent welds at each end.
= nominal leg size, mm or in.
throat size, mm
H
— 8--
flEZEZEZ
“
Stoggered H S Chained H---—S -
Millimeters
Size, Leugth. Spacing, and Thickness in Millimeters
1.ewser (hicknss of ot over over Vt-er Veer Over Over Over
,ueniher.s joined over 5 to 6.5 5 to 9.5 ii to 12.5 to 14.5
5 6.. to 8 9.5 t° ii 12.5 14,5 to 16
Length of Fillet Weld 40 (35 75
‘sorninal size of fillet u’ 3 5 6.5 6.5 8 5 8
‘sommnal size of fillet t 2 3 3 4 5 4 3 aS 5 3 5 5
Spacing S
Frames
To shell 1100 11(8) 3(X) 275 :300 275 250 250
SECTION 9j9 Welding

Millimeters
Size, Length, Spacing, and Thickness in Millimeters
Lesser thickness of Vat Over Over Over Over Over Over Over
members joined over 5 to 6.5 8 to .9.5 11 to 12.5 to 14.5
5 6.5 tO 8 9.5 to 11 12.5 14.5 to 16
Length of Fillet Weld It) 65
Nominal size of fillet w 3 5 ftS 6.5 S S 8 S
Nominal size of fillet t 2 3 5 4 5 4 3 5 ) 5 5 5 5 5
___________
Spacing S
Girders and Webs
To shell and to bulkheads
or decks in tanks — 2(X) 225 200 225 2(X) 175 150
To bulkheads or decks
elsewhere — 250 225 250 225 2(X) 175
Webs to face plate where
area of face plate is
<64.5 cm2 1 250 f 250 300 275 3(X) 275 250 250
Webs to face plate area
of face plate >64.5 cm2 250 225 250 225 2(X) 175
Bulkheads
Peripheries of swash
bulkheads — 200 225 2(X) 225 200 175 150
Peripheries of nontight struc
tural bulkheads — 225 250 225 250 225 200 175
Peripheries of oiltight or
watertight bulkheads In accordance with 9.9.4
Stiffeners to deeptank and
watertight bulkheads — 300 300 275 300 275 250 2Sf)
Decks
upper
Peripheries weld Cont. Cont. Cant. Cont. ICont. Cont. Cont. 5Cont.
of non—
tight Oats lower
weld 300 300 t300 300 300 300 300 250
Peripheries of
exposed decks, arid all
watertight or oiltight decks. In accordance with 9.9,4
(Fillet welds are to he staggered.
Nominal size of fillet w ma’, he reduced 1.5 mm (1.> in.
Nominal size of fillet w is to he increased 1.5 mm (1> rn
SECTION 91O Welding

Inches
Si:4, I1ogt/I, Sporing. tool 1hitwss in Incites
Lesser 1Iiuknes of ( 8cr (3ter ((reT Otr’r tIter (8 er (2rer
mc,,tI,ers joined .t 0.15) 0.25 0.32 0.38 0.44 0.50 0.57
oter to to to to to to to
0.19 (1.25 0.32 0.38 0,14 0.50 0.57 0.63
I .eitgih of Fillet Weld
Nominal size il fillet e I
Spacing S
Frames
To shell 12 12 12 1112 11 10 10
Girders and Webs
To shell, and to bnlkheads or
decksintanks — 8 9 8 9 8 7 6
To bulkheads or decks else
where — — 10 9 [0 9 8 7
Webs to face plate where area
of face plate < 10 in. 1 10 I 10 12 11 12 11 10 10
‘Webs to face plate where area
of face >10 in.2 — — 10 9 10 9 8 7
Bulkheads
Peripheries of swash bulk
heads — 8 9 8 9 8 7 6
Peripheries of nontight struc
tural bulkheads — 9 10 9 10 9 8 7
Peripheries of oiltight or
watertight bulkheads In accordance with 9.9.4
Stiffeners to deep-tank and
watertight bulkheads — 12 12 11 12 11 10 10
Decks
upper
Peripheries weld Cont. Cont. tCont. Cont. Cont. Cont. Cont. Cont.
of non—
tight flats lower
weld 12 12 12 12 t12 12 12 10
Peripheries of
exposed decks, and all
watertight or oiltight decks. In accordance with 9.9.4
I Fillet welds are to he staggered.
Nominal size of Fillet w na’, he reduced 1.3 mm in.)
Nominal size of fillet w is to be increased 1.3 mm in.
SECTION 9111 Welding

SECTION 1 0
Initial Testing and Maintenance
of C/ass Surveys
10.1 Initial Testing
In addition to the testing of the compartment parts as indicated
elsewhere in these Rules, the following tests are to be performed
in the presence of a Surveyor prior to placing the unit in service.
10.1.1 Tanks
Tanks are to be either air tested at a pressure of 0.14 kg/cm2 (2 psi)
or hydrostatically tested to a pressure of 0.14 kg/cm2 (2 psi) at the
highest point in the tank. Testing may be conducted after the appli
cation of special coatings, provided all welded connections are stir
veyed prior to application of the coatings and found to he to the
satisfaction of the Surveyor. Testing may he conducted either before
or after the 5PM is launched.
10.1.2 Cargo Transfer System
The entire cargo transfer system including hoses, swivels, and valves
is to be hydrostatically tested after installation to the design pressure.
10.1.3 Control and Safety System
All control and safety equipment is to be examined and proven
acceptable.
10.3 Maintenance of Class
As a condition of maintaining the SPM in classification the owner
is to notify the Bureau promptly of significant incidents as detailed
in para-10.3.1, is to carry out regular inspection and maintenance
and is to certify these actions to the Bureau as detailed in 10.3.2.
In addition, the owner is to arrange for the Special Periodic Surveys
by the Surveyor as detailed in 10.3.3.
10.3.1 Incident Reporting
The owner of the SPM is to notify the Bureau promptly of substantial
changes made to the structure, design conditions, cargo systems or
anchoring of the SPM. Review, approval or inspection, or combina
tion thereof, of such changes may be required by the Bureau as a
condition of maintenance of class. Routine replacement of hoses and
SECTION iou Initial Testing and Maintenance of Class Surveys

havsers, and tumor changes in the design or make—up in the hose
and hawser svstenis may be made after initial classing without notify
ing the Bureau provided the changes (10 not unfavorably effect the
performance of the parts of the 5PM and that the system as changed
is at least equivalent to the original system.
The owner of the 5PM is to notify the Bureau promptly of any
incident at the SPM which results in loss of life, in damage to coin
ponents of the 5PM. in damage to a vessel moored to, approaching
or (leparting from the 5PM. or in substantial cargo spillage. The
owner of the SPM is to notify the Bureau promptly of failure, break—
(lown, or substantial degradation of the hawser system, of any portion
of the structure which carries mooring load, or of the cargo system.
The Bureau may require a survey of such accidents, failures, break
downs, or substantial degradation and appropriate repairs and other
remedial action to be accomplished in a suitable manner as a condi
tion of maintenance of class.
The Bureau may require a special survey of the SPM if warranted
by incidents as a condition of maintenance of class.
10.3.2 Annual Reporting
The owner is to file a report annually with the Bureau certifying
that regular and annual inspections and maintenance have been
accomplished in accordance with an agreed schedule. Regular in
spection and maintenance is to include the following items.
I-lose and floatation apparatus
Cargo piping, expansion joints, swivels, seals and valves
Operation of cargo valves
f-Iawsers and mooring chains
‘avigation aids and safety equipment
Watertight compartments and hatches
Lubrication of moving parts
The frequency of regular inspections is to be appropriate for the
frequency of use of the SPM and for the environment, but is to be
at least semi-annual.
Annual inspection and maintenance, in addition to the above, is
to include the following items.
Pressure test of cargo piping, hoses, swivels, valves, etc. to the design
pressure
Mooring chain and anchor points
Tension of mooring chain
Underwater portion of SPM hull
Anodes
10.3.3 Special Periodic Surveys
For SPMs built under Classification Survey, the first Special Periodic
Survey becomes due five years after the date of installation. For other
SPMs a Special Periodic Survey becomes due five years from the
date of the original Special Survey for Classification.
SECTION 10j2 Initial Testing and Maintenance of Class Surveys

Subsequent Special Periodic Surveys are due five years after the
crediting date of the previous Special Periodic Survey. If a Special
Periodic Survey is not completed at one time, it will be credited
as of the end of that period during which the greatest part of the
survey has been carried out. The interval between Special Periodic
Surveys may be reduced by the Committee where necessary and the
Special Periodic Survey requirements may he modified in the case
of SPMs of unusual design.
The Special Periodic Survey is to be conducted by a Bureau
Surveyor on site. Arrangements for the survey are to be made 1w
the owner or operator of the SPM and all costs are to be borne by
the owner.
The Special Periodic Survey is to include the following in addi
tion to that required in 10.3.2.
Drvdocking or equivalent underwater inspection of the buoy. inter
nal examination of the buoy, including gauging after fifteen years
of service. Gauging may be required at an earlier date if deemed
necessary by the attending Surveyor.
lxamination of all anchor chain
Examination of all mooring components and accessible structural
members which carry mooring loads
l)is-assenibly and examination of all cargo hose, unless hose has been
in service less than two years
Pressure and vacuum testing of all cargo hose, unless hose has been
in service less than two years
1’:xaiiunation of safety equipment
SEC11ON 1O3 Initial Testing and Maintenance of Class Surveys

Abs 1975 single point moorings

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Abs 1975 single point moorings

Similar to Abs 1975 single point moorings (20)

Recently uploaded

Recently uploaded (20)

Abs 1975 single point moorings