[PSUBS-MAILIST] Brent Shaw , ambient sub

["Thijs Struijs" <thijs-struijs@planet.nl>]

----- Original Message -----
From: "CCN Prepress" <ccnprepress@ccn.co.nz>
To: <thijs-struijs@planet.nl>
Sent: Tuesday, March 12, 2002 4:15 AM
Subject: From Brent Shaw ­ New Zealand


> thanks for your comments about my drawing
>
> The more comments I get about safety and operational concerns the better.
>
> Your comments about the amount of air needed and petrol in an enclosed
area.
>
> The inner hull dimensions are 700mm(w)x1220mm(h)X3600mm(l). With ballast
> tanks attached it is 1300mm(w).
> All redundant spaces will be filled with a closed cell foam. I estimate
> about .7 cubic metre with all the bits and bods in to be compensated.
> Your thought that if the hull can't be pressure compensated it will sink
> like a rock confuses me. My thoughts are Example: a scuba tank fill of air
> will sink as quickly as a scuba tank empty. The empty tank will just
implode
> quicker.

A filled scuba tank will sink as quickly as an empty one. The tank can be
compared with a 1 atm. sub. At any depth the pressure inside will stay the
same. But you were talking about an ambient sub. You must not compare this
with an scuba tank but with an upside down bucket. If you run out of air
while going down the water in the sub will rise and you loose bouillancy
(difficult word for a dutchman). The only thing you can do is to release
your ballast or wait until the seafloor stops you. I think that especialy in
an submerged ambient sub you should not cross submarine canyons and hang
around steep slopes. Always make sure the waterdepth does not exeed your
fysical abillities.

> Petrol is to be stored and a standard marine fuel tank with 2 one way
> breather valves. one is for air into the tanks and  the other is for
> relief air compensation in the tank and that is to be vented to the
outside
> of the hull. With this valve valve system there will be no petrol fumes
> leaving the fuel tank into the cabin. An electric fuel pump will be used
to
> feed the 20hp motor.
>
> Why do I even want a petrol motor. (for performance and size)
>
> I plan this craft to be launched from a standard boat ramp and then be
able
> to power out to the dive spot without the use of compressed air and
electric
> amp/hr power. I estimate a surface speed of around 15 knots on the plan
and
> a submerged speed of around 4 knots
> In New Zealand there are small islands dotted right around our coastline,
> most of which are 1-4km off shore, and there is some amazing diving out
> there.
>
> More comments would be appreciated.
>
> from Brent Shaw

I don't know much about petrol motors in submersibles. I am sure others will
advise you on the subject. I can imagine that you want to build a sub with a
big range. Particulary compared to the dutch mudy waters New Zealands must
be a great place to be.

Good luck,

Thijs Struijs

>
> email: ccnprepress@ccn.co.nz (this is work)
> and: divedrynz@yahoo.com (personal)
>
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