Wave absorbing systems as opposed to wave breaking. A short presentation of an innovative system to absorb wave energy, to protect coasts from erosion to create ports and other protected sea areas

1. Technical data sheet 4.1
Floating wave absorber with vertical Model:
moorings and excess buoyancy KIMODOKI
Offshore Energy Mission
Systems S.A. Floating wave absorbing system for the protection of coastal and offshore installations from the sea
waves, with applications in marinas, fishing harbors, anchorages and in general port construction, for
48 Karaoli & Dimitriou Str additional protection of existing ports and for the protection of coasts from the waves and from erosion.
152 32 Halandri, Greece
Tel. +30 210 6775 003
fax +30 210 6812 770
www.offshoresystems.gr
tech@martech.gr
Floating W.A. in Lavrion, Greece— Pilot installation for a research project
Technical characteristics
• The system consists of standard modules with typical dimensions 12m x 3m x 4m (LxBxH) that are
connected together to form the final assembly.
• The connections can be parallel, longitudinal or oblique for the formation of a structure with the re-
quired dimensions and shape, depending on the geographical characteristics and the wave patterns of
the protected area and the desired absorption ratio. The typical breadths of the final absorber are 3m,
6m or 9m.
• The connectors are specially designed and constructed to allow the desired connections and to absorb
the vibrations that are the applied on the structure.
• The body of the wave absorber is a steel lattice type structure consisting of welded and bolted stan-
dard parts that are manufactured in fully industrialized conditions.
• In order to protect the structure from corrosion all steel parts are hot dip galvanized and additional
protection measures are applied to the boot-topping area.
• The buoyancy subassembly consists of a) fully submerged horizontal and partially submerged verti-
cal polyethylene floats filled with polystyrene and b) fully submerged polyethylene floats that can
filled with ballast water. The ballasting allows the control of the system’s draft and natural frequency
(in order to avoid resonance with the incoming waves) and the creation of excess buoyancy.
• The mooring system is composed of vertical mooring lines, which in conjunction with the excess
buoyancy allow the system to operate in areas with deep waters and be effective in absorbing the en-
ergy of a broad range of waves.
• The absorbing subassembly consists mainly of foil type units with horizontal and vertical slopes that
gradually deflect the incoming wave and absorb its energy, while at the same time cancel out the ex-
erted forces inside the structure.
• The deck of the wave absorbers consists of hot dip galvanized steel grating.

2. Basic use and equipment
The main use of the wave absorber is the creation of protected coastal and offshore areas. The standard
edition of the w.a. includes all necessary equipment and fittings, such as mooring system, steel grating
deck and ballasting system.
Offshore Energy Advantages - Range of applications
Systems S.A. The wave absorber system is a patent of our
48 Karaoli & Dimitriou Str company (Greek Industrial Property Organiza-
152 32 Halandri, Greece tion patent No. 1003786/2002) that was devel-
Tel. +30 210 6775 003 oped in the context of a research program par-
fax +30 210 6812 770
www.offshoresystems.gr
tially funded by the Greek Secretariat of Re-
tech@martech.gr search and Technology.
The advantages of the wave absorbers can be
summarized as follows:
• No permanent structures are required that in
general disturb the environment and the
natural flow of the water creating pollution Wave absorber module
sources in the inner port basin.
Wave absorber ready to be installed
• The system operates by absorbing the wave
energy instead of breaking or reflecting the
waves that lead to the creation of standing
waves outside the basin eventually causing
serious problems to vessels approaching the
port.
• Due to the wave absorption (instead of the
usual deflection) no erosion is developed in
nearby coasts, a phenomenon that is com-
mon in all permanent port structures.
• The floating wave absorbing system are ef-
fective against a broad range of waves,
unlikely floating breakwaters that are effec-
tive only in partially sheltered areas charac-
terized by waves with small height and peri-
ods.
• The natural frequency of the wave absorbers
can be adjusted according to the characteris-
tics of the installation area (water depth,
wave particulars) so that to avoid the reso-
nance of the system to the incoming waves.
This in conjunction with the absorbing units’
characteristics help to minimize the loads
applied to the structure and to abate the
Innovative design of a marina in Kalomos, Greece using floating wave
wave induced movements of the system. absorbers and absorbing quays
• The wave absorbers do not suffer from run-
up incidents that are common in permanent
gravity and in some floating structures,
which allow the wave energy to reach the
inner port basin causing significant prob-
lems.
Additional use and equipment
A wave absorber installation can under certain
conditions be used as a wharf as is or in combi-
nation with floating docks (type THOI).
In this case, the additional equipment includes
additional mooring lines (catenaries), bollards, Absorbing subassembly
wooden deck, rubber or wooden fenders and
protective rail.
ΕΕ1.1150-06 (EN) | Α-01 | 17-02-2010