[PCW] Inflatable power catamaran

[Malcolm Tennant]

Robert Deering.

Dear Robert,

A number of my sailing catamaran and trimaran designs are flexible in a
similar way to the original polynesian vessels and those of James Wharram.
In this James and I follow a very honourable tradition as all of the
catamarans designed by the various Herreshoffs, and their contemporary
Thomas Fearon, were flexibly coupled. Similarly, a number of Meade Gougeons
trimaran designs had flexibly coupled floats.

Some of the early steel and aluminium ferry boat designs had the
superstructure mounted separately on air suspension bags. This was mostly to
isolate the engine noise in these all metal structures. It is no longer done
because you essentially had to build two structures that had to be capable
of standing alone separately and the result of this was that the overall
structure was heavy.However this is not the same as a "flexible suspension".
If you are designing/building a vessel that is completely open with very
little accommodation like the blowup boat then such flexibility can be
relatively easily achieved. However if you want a vessel with the usual
amount of accommodation then it is much more difficult. It will be heavier
and much more expensive as flexible couplings will be needed for all piping
etc[ unless each module is completely self contained]. Unless the boat is
for some highly specialised purpose where such flexibility is considered to
be an advantage,then the added complexity, weight and cost just doesn't seem
to be worth it.

Regards,

Malcolm Tennant.

Malcolm Tennant Multihull Design Ltd
PO Box 60513 Titirangi,
Waitakere 0642
NEW ZEALAND

ph +64 9 817 1988
fax +64 9 817 6080

e-mail malcolm@tennantdesign.co.nz
www.tennantdesign.co.nz
www.catdesigners.com