Australian BRUCE ROBERTS SITE
What are CUTTING FILES & Assembly PLANS ?
notice that we offer "Cutting files and Plans" for some some of our boat
kits. What does this mean ? These Cutting Files are the same AutoCad files
that we send to to our cutting shop for the kits to be cut for delivery world-wide. If you
prefer to have the kit cut by a local cutting shop, then we can supply the files on a CD
that will enable you to have the kit cut locally.
Above are 40 sheets of 18' x 4' of steel
plate laid out showing the cutting & reference lines.
This is the same set of parts cut and laid out as they will be assembled into your hull deck and superstructure. There is a lot more information all about the cutting files and kits in the book METAL BOATS.
This is the type of machine your local cutting shop will use to cut out your kit.
PREPARATION OF CUTTING FILES: Many
of you may be surprised that it is not possible to take a regular boat plan even one that
is already prepared using the latest computer aided design techniques, and use it for
automatic computer controlled cutting. There are many steps between creating the original
design and having the boat cut out on a computerized plasma-oxygen cutter. If a particular
design is destined to be available as a pre-cut steel or aluminium hull, deck and
superstructure package then this should be decided at an early stage in the design
program. Some designs can be converted but it is preferable to start with automatic
cutting in mind.
The main steps in preparing a new design for a boat that is destined to be cut out
by a computerized plasma-oxygen cutter is as follows. Firstly it is usually the customer
who gets the process started by contacting the designer with a brief outline of what they
have in mind. Further correspondence quickly establishes the clients wish
list. The list usually includes things such as type and style of boat, intended
usage, overall length and beam. Draft limitations should be specified at this stage.
Accommodation requirements, number of regular crew as opposed to occasional guests
should be stated. Speed requirements are important as are the clients attitude to fuel
costs. This list may need some refining as some elements may conflict one with the other.
It is part of the designers brief to ensure that the client ends up with a boat that meets
most if not all their desires and overall requirements.
So far the process is very similar to what would be
followed no matter from which material or building method was to be used to construct the
The next step is that the client and designer enter
into a (in our own case) simple agreement where the designer agrees to prepare preliminary
plans for the proposed vessel for a reasonable (a relative term!) fee. In our office we
consider that the lines plan, general arrangement drawings consisting of exterior profile,
deck plan, accommodation profile and plan views plus sufficient calculations to ensure
that the final design can meet the clients requirements, constitutes a Preliminary
Before a preliminary plan can be produced it is
necessary to produce a 3D computer generated model of at least the hull of the vessel.
Once the preliminary plans are completed and both the designer and the client are
satisfied with the overall concept and layout of the vessel then we can proceed to
preparing the complete plans for the vessel.
For the design to move forward it is now necessary to
complete the 3D computer model that would at this stage need to include all items such as
hull including transom, keel and rudder, all decks, cockpits, complete superstructure,
main interior bulkheads and any other features such as flybridge, radar arch, exhaust
stack. Special items such as transom steps and other similar features are all included in
this model. Depending on the complexity of the design, this process can take between 80
and 200 hours.
From this model all of the salient hydrostatics such as
detailed weight calculations to enable material requirements and final displacement to be
calculated. This allows stability calculations to be made at this time. During this
process fine-tuning of the model can be undertaken to make sure that the finished vessel
will meet all the design requirements.
Once the 3D model is completed and checked, then copies
of this model are provided to the specialized designers who prepare the final model that
includes all the scantlings such as transverse and longditunal framing, sole bearers, deck
beams and engine beds. This same team then separate out all the parts for the frames,
stringers, engine beds, bulkheads, hull, deck and superstructure plating etc., and add
notches to the frames and bulkheads before nesting the parts on plates.
The design team put the correct number on each item and
also reference lines are drawn on each part to represent frame locations etc. The purpose
of the numbers is to identify each part and the lines are used during the assembly process
to locate frames and other structural members.
Next it is necessary to work out a path for
the computerized plasma-oxygen cutting machine. The path is the point at which
the cutter enters the plate and starts to cut the parts. In addition, the path has to
determine which part is cut next and so forth. This is all necessary so that the parts are
cut in the correct order. For instance, if a window has to be cut from a cabin side, then
the window aperture must be cut before the larger cabin side part is cut otherwise any
movement in the cabin side after cutting could cause the window to be cut in an incorrect
ASSEMBLY PLANS: The assembly plans we supply with the CUTTING FILES or KITS cover several sheets of drawings and include all the information that your will need to assemble you kit. Also included are several sheets of engineering drawings showing lay-out of your engine room, exhaust system, steering system, fuel and water thanks etc.
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