Re: Ballast Bladders

["Marcel Michaud" <michaudr@telusplanet.net>]

-----Original Message-----
From: Morrisson, Richard D <Richard.Morrisson@PSS.Boeing.com>
To: 'personal_submersibles@psubs.org' <personal_submersibles@psubs.org>
Date: Wednesday, November 04, 1998 9:08 AM
Subject: RE: Ballast Bladders


>Marcel,
>A suggestion.  Instead of meticulously trying to get rid of all the air in
>the bladder when packing it (like a parachute), try submerging it in water
>and getting rid of the bubbles while packing.  This would leave a little
>water in it to keep the surfaces from sticking together when compressed and
>to take up those small spaces which would otherwise be compressible pockets
>of air.  The water will neither add to or subtract from your overall
>bouyancy.
>Dick Morrisson
>
>> ----------
>> From: Marcel Michaud[SMTP:michaudr@telusplanet.net]
>> Sent: Tuesday, November 03, 1998 8:06 PM
>> To: personal_submersibles@psubs.org
>> Subject: Re: Ballast Bladders
>>
>> Ray Keefer wrote:
>> >
>> > Hi Martin,
>> >
>> > > Is anyone using soft external ballast bladders for emergency ascent
or
>> > > surface  freeboard?
>> >
>> > Yes. I always thought of using some kind of bladder or lift bag as an
>> > emergancy bouyancy device. I would use soft ballast tanks for regular
>> > usage. But if they get damaged like in a collision I would like to open
>> a
>> > valve and pop open the emergancy bouyancy bags.
>> >
>> > > Unfortunately, there are some other problems,like containment of the
>> > > inflated bladder,  possible bursting as you ascend, volume of blowing
>> air,
>> > > reliability etc.
>> > >
>> >
>> > I would put them in flat boxes on the upper hull. The boxes would
>> protect
>> > the bags from wear and tear but would open up to let the bag out.
>> >
>> > The air pipe would be  located inside the bag with possible a length of
>> > flexible tubing. In any cases the opening of the bag would be centered
>> above
>> > the air pipe. The bottom of the bag would be open. So fill it up at
>> depth and
>> > as we ascend the expanding air will just leak out the bottom.
>> >
>> > > Any comments?
>> >
>> > Always. :)
>> >
>> > Regards,
>> > Ray
>
I though about this solution , I would have to fill those bags every time I
would put my sub in the water, not a big job  just though  someone would
have a better idea regarding this.

I use a ultralight dry suit sometime for diving , I have been using it for
years, I think the material would be good for this application it's very
light and strong, just think it would be good stuff for this application.

The deployment of these bags would be a one time thing for sure, till the
next time you dive again and I am sure I would not want to use it again,
but for emergency only.

In 1988 I built a ROV, and with it I found a plane owned by American Export
Air Line, four engine transatlantic plane, the name of the plane  is called
the Flying Ace it crash in 100 ft of water in 1943 in Botwood Newfoundland
Canada on it's way to Ireland from NewYork, anyway while surching for this
plane we ended up sitting the ROV on a big bed of silt, looking at the
monitor at the time we could not tell the depth of this bed because we could
see star fish on top of it.

When I tried to take the ROV up  it would not come up with the thrusters at
full speed, so we pulled on the umbilical cable a bit but was afraid to
damage it, so we suited up and after a 75 ft dive  to the unit found the
problem, the bottom or base of the ROV was  in the silt sunk about 12" when
we tried to free it we found the silt to be 3 ft deep.This silt is found at
the mouth of a large river running into salt water on the river is a paper
mill that's been there a 100 years.

 All this to say that I may have deploy these bags on the bottom.

Marcel