[PCW] Endeavor: "Form following function?"

[Malcolm Tennant]

I would like to add some comments to this discussion from a designers point of
view.

Firstly, lets just hark back to the Catalac. It was originally designed for
plywood construction, as evidenced by its hard chine hull [typical of Bill
O'Brien designs]and boxy cabin. It would be hard to imagine shapes less suited
to glass fibre construction, and solid glassfibre construction at that. Never
the less when it was put into series production they just reproduced the
plywood boat. No attempt was made to take advantage of the properties of glass
fibre or the advantages concerning shape, styling and surface finish that
female mould production in glass fibre imparts.

One of the questions that a designer asks when he approachs a new design is
"How is this boat going to be built?' ie: is it going to be amateur built by
relatively inexperienced people, is it a more up market one off being built by
professional builders or , is it intended for series production?  The design
for amateur construction will probably feature mostly flat panel construction
with perhaps a few styling features like rounded corners, cabin overhangs etc
just to take the boxiness off. One of Its main priorities is ease of
construction but this emphasis does tend to have styling consequences and may
impose limits on the boat.

The professionally built one off design will feature a lot more styling. But
not too much. As the "fancy Eurostyling bits"  such as are seen on "Pacific
Harmony" can add significantly to the price. But the professional yard will
probably have CNC cutting machines that can produce more complex shapes from
the designers computer files and considerably mitigate the cost penalty.

 If the boat is going into series production then the designer can do a lot of
things to improve the appearance of the boat over that of the amateur built
boat. The reason for this is very simple. You may build 300+ boats of this
design but you only have to build the plug ONCE. So you may as well go the
extra mile with the plug and moulds and incorporate features that would be
prohibitively expensive in a one off because it will certainly pay off in the
long run. Plugs and moulds are very expensive anyway and so putting the effort
into the original design to make it easier to build,more appealing and with a
good finish adds very little to the cost of the moulds. This is especially
true in these days of surface modelling, CNC profile cutters and 5 axis
milling machines.


The original design cost is a very small percentage of the total development
cost of a vessel. That this is true of most consumer products is taken very
seriously by most manufacturers. So why not power catamaran builders?

Regards,

Malcolm Tennant.

MALCOLM TENNANT MULTIHULL DESIGN LTD
PO Box 60513, Titirangi.
Waitakere 0642
NEW ZEALAND
Ph: +64 9 817 1988
e-mail: malcolm@tennantdesign.co.nz
www.tennantdesign.co.nz
www.catdesigners.com