> I've wondered from time to time about pressurizing the fore and aft
> sections as a way to increase overall strength of the boat. Cola and beer
> cans, as well as jet airliners, are much stronger when pressurized than
> when not.(Crush a full unopened can; crush it after consuming the
> contents. In aircraft, as I understand it, loss of cabin pressure is
> dangerous more because of the loss of this strength, not just the loss of
> breathing air). Even 5 to 10 psi might be enough. One could more or less
> reverse the normal hatch flange so that pressure from inside would press
> the hatch out, and into, the seal gasket. Pipeline access manways are made
> that way, in an oblong shape so that it can be removed by lowering then
> rotating.

> Then, as if to compensate, the central section of the boat could be
> reinforced with more glass to prevent the cockpit section from folding in
> extreme conditions.

> Something of a pipe dream, I know, and it would take an engineer or two to
> figure out what could be expected. I know pressure vessels generally do
> not have acute interior angles such as you'd find at the bow keel. I don't
> see any weight savings; in fact, reinforcing needs may require extra epoxy
> & glas in places it wouldn't otherwise. So, for the same weight, or
> more, maybe a stronger boat is possible.

> I'm just not sure 'WHY?' do it, except as research.

> Back to the original question:

> My Pygmy Coho instructions said to do the bulkheads and hatches AFTER the
> boat was built, so I did. And the whole time I wished I'd done it all at
> the step just before final attaching of the deck to the hull. As it was
> all pretty well shaped and fairly stiff at this point, I don't think any
> distortion would occur providing you were carefull.

> Clamping a scrap accross the sheer would hold the hull while the bulkheads
> were fitted and epoxied in place. Leave, say, a 1/8" gap on the top
> to keep it from pushing the deck up. This would leave just that one edge
> to fillet and glas from inside the boat afterwards.

> Likewise, the hatch flange installation would have been easier, as well as
> a little neater.

> On the other hand, I haven't heard of others complaining about doing it
> the way Pygmy's instructions said to. I just had trouble, particularly in
> the front, getting an arm, my head, and a lamp in there and still have
> room to move. Maybe all three are just a little too big, eh? I tried to put the bulkheads in before putting the deck on and found it to be a real pain. I wired the deck on for stablity and tried to trim and fit the bulkheads, I finally decided that it would make fitting the deck on very difficult and decided to abandon the idea. I did glue in fittings for the foot pedals with T-bolts and did not have any problems.