Case 1.
To Build a Production Power Boat
A Production Power Boat
• The boat itself is Length 8 M, Beam 2.5 M, DISP 3200 KG,
HP 225 Yamaha Outboard.
• What is production?
• To mass produce, or to build enough boats that it
becomes an advantage economically
• The number of boats built to become economically
viable depends on the method and the tooling outlay
• What are the construction options and what tooling do
they require
• FRP. Aluminium, Plywood Composite
FRP Production
• This is the most common method of building a number of
boats economically
• The tooling required are a set of moulds which are usually
female and can be made up of Hull, Deck and Cabin Top,
interior structure, and interior liner
• To make the mould a plug is required
• The plug is finished to a high standard and the mould is
laminated on the surface of the plug to form a female mould
• A very similar process to the lamination of the finished parts
in the female moulds
• The tooling (moulds) for this construction technique are
expensive to build, there is a high initial outlay
Aluminium Production
• The building of Aluminium production boats is more recent
than FRP and is very successful particularly in the size range
under 12 metres
• The success of Aluminium as a boatbuilding material is due to
several factors, its strength to weight and the fact that it does
not require painting
• Tooling is less expensive than FRP, boats are built from pre cut
panel shapes either using C&C router or by hand made
patterns
• In this way entire boat kits can be pre cut, fitting together by
welding
Plywood Composite
• This method of building boats dates back to the 1950’s
• The combination of Resin, Plywood, glass fibre and foam has
become the material combination used for one of, or limited
production building
• We could really call this construction composite and although
plywood is a substantially heavier core than foam it is less
expensive and stronger than foam
• The tooling for building boats in this method is probably the
least cost although a job lot of patterns should be stored for
every boat built
• Because the other two production construction methods are
more efficient for reasons we will investigate, plywood
composite is more suited to one or several boats
Comparisons of Methods
• The outlay in the cost of tooling to build an FRP production
boat means that design alterations can not be considered
• The success of a production build relies on many factors such
as careful market analysis, Quality building techniques,
marketing of product, and location of the operation.
• Aluminium boatbuilding is noisy, welders are employed along
with boatbuilders to piece together the components
• Aluminium boats are most suited to a developed hull (conical
development)
• Both FRP and Composite construction allow any hull shape to
be built
• All modern factories must provide safe working environment
for staff, and the ability to control temperature and humidity
to ensure modern products are applied successfully.
Methods of Construction
FRP
• A typical FRP construction will take place in a temperature,
humidity controlled environment
• Once the moulds are prepared the laminate process will
either be by hand lamination or by chopper gun
• The Gel coat is sprayed onto the surface of the mould and let
to tack off before the laminating commences
• The process is quick in Boatbuilding terms
• Finished product is generally quite heavy compared to
aluminium or Composite
• The product comes out of the mould with one finished gelcoat
surface
Methods of Construction
• Aluminium construction for a production boat is reliant on
C&C cut components assembled and tack welded to form the
hull, decks, and cabin
Aluminium Construction
• Aluminium is a material which is suitable for different
methods to be used to form up the boat
• The material itself forms a protective surface when exposed to
UV rays, this means that there is no necessity to paint other
than for appearance
• Aluminium is Isotropic
Plywood Composite
• This is a very good and proven method of constructing boats,
however it is not as well suited to production building.
• The surface of the plywood needs to be protected with epoxy
resin to avoid dry rot, the epoxy must be protected with a 2
pot paint system to avoid UV damage
• This means that there is a large amount of cost in protecting
the substrate of a plywood or wooden boat
• On a more positive note wood is light, strong, and the finished
article can be superior in finish and performance
• Boats of any design or shape can be built of plywood, timber,
foam and glass cloth.
• The modern wooden boat is a composite construction not to
be compared with carvel construction
Advantages and Disadvantages
Positive
• Any shape of boat can be built in wooden composite style and
new boats can be altered to suit owner requirements and
performance improvements
• There is little tooling cost in plywood composite construction
• Plywood composite does not have the condensation problems
of other materials
• FRP boats are produced quickly with markedly less labour cost
and are rot free.
• FRP boats retain their value because there are many of each
design
• FRP vessels have market acceptance
Advantages and Disadvantages
• Aluminium boats are rot free
• Aluminium boats can be constructed as a production boat
without the high cost tooling
• Aluminium boats do not need surface coatings except
underwater
Negative
• Plywood Composite boats are slow to build, therefore
expensive by comparison
• Aluminium boats tend to look commercial when unpainted,
they are prone to Galvanic corrosion problems
• FRP moulded boats are not able to be altered to keep up with
modern design ideas, because of the limited life of gel coat
there surface finish can break down in a relatively short time
•
END