Re: [PSUBS-MAILIST] Dry ambient concept

["Alexander Foreman" <alexforeman@mailworks.org>]

Sorry if I don't answer your emails fully - no time. But I am lapping up
the info.

I have been reading through the archives and am now just finishing 1998.
The more I read the more excited I get.
This group is fantastic for motivation as well as info.
I haven't found the trailer discussions yet.

If anyone is interested - here is my current thinking on my sub:

Hull material - I am now definately leaning towards steel. Fibreglass and
FRP look like mongrels to work with. I have a friend who is a crash
repairer and another who owns a barramundi fish farm. Both are willing to
lend welding equipment and teach me. I think I will follow Pierre's
example and weld flat plates over a frame. Not elegant but simple.
     Had my first go at metalwork today. I cut up the ventura rack on my
     wife's Kawasaki GTR1000, painted it and then fitted a topbox
     bracket. Not too bad for a non-handyman. My crashrepair mate wasn't
     so impressed though.

Cabin - My wife demanded that she also be allowed to go submarining. I
will enroll her in a scuba course and have modified my cabin design. The
cabin now displaces 36 cubic feet. It should fit one person in very good
comfort or two fairly tight. She looks good enough that I won't complain
about the squeeze. 8-)

Air - I think I will need about 400 cubic feet of compressed air. I want
to operate between 0 and 100 ft depth. Mostly above 50ft. Am I right in
thinking that 100 cubic feet released into the cabin will maintain an
ambient cabin pressure to nearly 100 feet. *I do mean a proportionate
release of air as the boat dives, not a sudden release!
      100 cubit feet of air supplied per person and 100 to compensate for
      depth adjustment at target depth.

Weight - I think I will have to accept 1000kg as a working weight.

Propulsion - Sports sub style, 2 motors each side that tilt up or down.
Vary power to steer.

Configuration - This is a tricky one. I want a forward mounted cabin with
excellent forward and downward visability. Unfotunately this leads to all
equipment being behind or to either side of the cabin. I am thinking of
mounting airtanks behind, ballast tanks either side, battery box
rearwards underneath and lead ballast forward underneath. Makes the boat
a bit stumpy. Some sort of fairing on the back should help with drag.

Built in trailer - I have LOTS of Qs but will read the archives first.
Again I think Pierres method is probably more practical.

On Tue, 9 Mar 2004 13:01:13 +1100 (GMT+11:00), "Peter McKellar"
<mckellar@earthlink.net> said:
> Hi Alex,
> 
> FRP is Fibre (glass) Reinforced Plastic (maybe polymer) to the best of my
> knowledge (and shoot me down folks if I am way off here).  Basically the
> same stuff used to make surfboards, canoes and lots of marine craft.

> However, I do have one tip: if you are looking for large amounts of
> fibreglass matting and 
> resin, go straight to a custom-surfboard manufacturer. The little guys 
> who work out of a shed, and they can sell you mounds of the stuff at 
> about 25% of hardware-shop prices.

Hehehe, all the surfies get eaten around here. One got taken a couple of
months back at cactus beach. A spear fisherman was chewed up a few weeks
later. But they keep on trying.
No surfboard makers in town 8-(
 
> The reason I issued the Aussie Roll Call was to swap notes onlocal
> suppliers - no doubt you have experienced getting hold of technical
> things can at times be easy but is more frequently impossible, expensive
> and/or you must wait up to 3 months for it to be imported :(  Erik
> (ex-pat oz) passed on this:

I am yet to find a local source for submersible motors, which is odd
considering that a large number of boats are manufactured here. May have
to import one.

Bob Duncan wrote:
>   F.R.P. Fiber Reinforced Plastic or fiber glass. People of the United Stated don't >like the word plastic, because it is associated with cheap toys made on the other >side of the world!!!

The Australian Army uses a plastic rifle called the AU-Styre. The thing
is absolutely wonderful. It can be run over by a tank and still fires
accurately. It can be destroyed by sunscreen though, something we use a
lot of here.

Could anyone comment on the problems and difficulties of working with FRP
or Fibreglass? From what I have seen they are not easy materials to work
with.

Shawn wrote:

>The two methods of working with FRP that I've used have been with a "cutter", >spraying into molds (like fiberglass shower stalls are made), and in matte form over >a frame and/or foam core (e.g., surfboards).

I presume that the frame would have to have a layer over it of some kind.

>Personally, I wouldn't recommend FRP for 1-atm applications because it's not a >homogenous material.  It's been done, but the tendancy to fracture with impact would >be a very real concern.  For an ambient, though, FRP would be my choice simply >because the skills are relatively easy to learn and the tooling minimal unless you go >the cutter and mold route.

BLOODY SUBMARINES:
This is bad for me I'm sure. I am lying awake in bed because my brain is
full of submarine!
-- 
Alexander R Foreman
Port Lincoln, South Australia
Sub - Research stage only
    - Small dry ambient

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