materials in building ship

1. SHIP MATERIALS
MEETING 4

2. AGENDA
• Material issues in ships construction
• Types of materials in ships construction

3. Properties of Materials in Ship Constructions
• Strength
• Weldability
• Toughness
• Marine Corrosion
• Formability
• The Cost

4. Strength
• The materials used in building the ship must have strength
• The materials are tested to ensure their strength, ductility, and
toughness are suitable for the function they are required to perform
• In comparing the strength of various metals stresses and strains are
often referred to and require to be defined
• Stress is a measure of the ability of a material to transmit a load, and
the intensity of stress in the material

5. Weldability
• Welds in a ship structure are also
very critical to its overall strength,
durability, and toughness.
• Even small defects in weldments
can create the initiation point for
considerably larger cracks and
eventual failure

6. Toughness
• In shipbuilding, toughness is a
critical feature of the structure and
its component materials (both plate
and weld metals
• Must be able to deform plastically
to some extent, and tolerate cracks
while maintaining overall structural
integrity

7. Marine Corrosion
• There are various materials
options, design strategies,
coating, and cathodic
protection technologies
available to the designer and
shipbuilder

8. Formability
• Formability is the ability of a given
metal workpiece to undergo plastic
deformation without being
damaged
• Formability of the grade impacts
toughness, weldability, and
strength

9. The Cost
• Choosing the cheapest material
in the construction phase
cannot be a considered a
success if the decision requires
a significant increase in
construction labor or creates a
maintenance nightmare during
the 30 to 50 year

10. Construction Materials
• There are 5 basic materials used in modern ship construction
• Steel
• Aluminum
• Wood (Traditional and Moulded)
• Ferro-Cement
• Fibreglass/GRP/FRP
• Typically moulded wood, fibreglass and ferro-cement do not use
traditional construction methods. They have methods specific to
each type.

11. Steel
• Very strong, easy to work with provided proper training
and equipment are available
• Before welding, which was invented in the early 1900’s,
vessels were riveted. Kajama is an example of a riveted
ship
• Nowadays all ships are welded (including Pathfinder and
Playfair)

12. Steel Continued
•Welding is a very quick,
cheap and easy way to
construct a high strength
vessel
•It allows for easy modifying
and repair, with basic tools
•Steel corrodes over time,
but modern coatings are
very effective

13. Aluminum
• Very light, very expensive
• Worked in basically the same way to
steel, but welding it requires special
equipment and training which leads to
higher production and maintenance
costs
• Aluminum is a lot more susceptible to
electrolysis and corrosion, so more
care must be taken

14. Wood (Traditional)
• Very laborious, requires high skill level for quality construction and
repairs
• Creates beautiful, unique vessels

15. Ferro-Cement
• A steel mesh (the Ferrous part) is used to construct a mold.
This mold is covered in layer upon layer of cement
• This method is relatively cheap, relatively easy and allows
some very intricate designs
• It can be strong if done well, some Ferro-Cement boats are
still afloat after almost 100 years!
• It can also be a very unsafe method if done improperly, and
good hull inspections are next to impossible

16. Fibreglass/FRP/GRP
• Cheap, especially for
production of a lot of one
design
• Pretty easy and cheap to
maintain
• Not at all traditional

18. Moulded Construction
• A mould is constructed to build the ship on.
• This might be a concave mould, where the material fills in the mould
• Or it could be a convex mould where the material is spread overtop of it

19. Wood (Moulded)
• Uses strips of wood and lots of
glue between layers. Sometimes
fibreglass is used between layers
as well
• Creates a very strong form, with
lots of opportunity for unique
design
• Difficult to modify and repair