"DSK" wrote in message
. ..
No reason why other boats couldn't have positive flotation.


JimC wrote:
Actually, there is. If conventional boats with heavy, weighted keels,
particularly those of heavy construction, had enough positive flotation
to keep the boat afloat, there would be little room left in the cabin.

Bull****.

How much volume does the boat have immersed (ie below the waterline)? The
is the exact amount, no more. "Heavy weighted keel" or any other sort.

You are correct, but I'd be interested to see the volume of flotation
material needed to compensate for that displacement of water. *The volume
of flotation material required to offset a given volume of water is not
necessarily same.* Lear Siegler, the builder of O'Day boats, published a
lengthy report some years ago about why larger boats don't have positive
flotation. It was written from an engineering point of view and made sense
to me at the time, albeit I'm no engineer. Their point was essentially what
Jim C was claiming--loss of interior volume in a marketplace demanding more
and more interior space. They even explored the concept of flotation that
could be inflated in crisis, but cited cost and space requirements for even
this more compact system. So I'm not quite sure Jim is wrong. Can you
provide some documentation to the contrary, beyond just your opinion?

Now, if you're talking about a flush-deck boat with 2' of freeboard, then
maybe there wouldn't be much cabin room to spare... there wouldn't be much
in the first place.

Positive flotation probably wouldn't be offered by manufacturers
voluntarily. It would most likely be the result of a government requirement
(there's that nanny state again, Doug), and it would have to be applied to
all boats, regardless of design. So according to your last paragraph, such
a ruling might eliminate a whole class of boats. Small class racers like
the Mumm 30 come to mind.

Max