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Hi Frank,
I was originally looking at fibreglass and flagged it away as a bad idea,
as its more dodgy and harder to nail down the actual strength of what you
are building . You also need to go thicker to get the same strength wich
means more displacement and hence the sub has to be made heavier to sink. Metal
is inherently heavy but with fiberglass you have to buy a lot of lead to sink
it.
I started this project with the radical thought of "why can't you build a
sub that fits in the back of a stationwagon" (look at newt suits). My original
steel sub design required a 650mm sphere wich I couldn't get made in Australasia
and decided Europe and US was outside my budget. I then looked at doing a
fiberglass ambient sub.
After investigating this with psub help, was a bit disapointed
with this option. Jon posted a link to a plastic 1 atmosphere sub wich
got me thinking, and after running my ambient design through a pressure
programme found I wouldn't need to go much above an inch thick at the most
critical points to get a 2000 ft crush depth.
I'm designing my sub out of a block of polystirene that I've sliced
horizontally and hollowed out. When I get it right I'll push a lots of pins
through from the inside, sand back to the pin level, fiberglass over the top and
disolve out the polystirene, then add reinforcements etc. I'm also planning on
inflatable ballasts so I'm not dragging round a couple of hundred kilos of
water. My design process has been hands on, sitting in the poly block, trying
the dome on, building jigs for seating angles, making cardboard batteries and so
on, so I haven't got anything to show re designs. I look forward to the point
when I've got pictures of the hull to post.
The epoxy suits my design process and should be simpler than using
metal. However if I was doing something bigger fibreglass wouldn't be worth
while.
Regards Alan
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