RE: [PSUBS-MAILIST] Diving Catalina Island

As soon as I realized what was happening I pulled my air release cord on the other side of the BC, but since the air was expanding as I was accending I couldn't get rid of the air fast enough. It seemed like I had a lot of air coming out of my mouth and I was breathing outward as I was accending, I wasn't breathing out hard but steady. I didn't feel any problems with my body, we were not in a deco dive frame. Before this happening I had not really considered it as something to be careful of. The air inject and the air expel buttons are right next to each other on my BC the only difference is one is bigger than the other.

Doug, on your boat if you had a hard ballast you would be able to control it better, but then it would probably change your whole design and add more cost also.

When I first learned to scuba dive we didn't have BC's I think we had some sort of saftey vest for the surface. If you didn't use your BS you would have to be dialed in pretty closely to be neutral buoyant .

I've been having the same thoughts lately as I've been installing my vents from my ambient trim tanks.

I decided on 1 1/2" vents for what a guess will be about 10 to 12 cubic feet of air in the forward and largest tank when starting an accent.

So I counting being able to vent 12 cubic feet through a 3 foot 1 1/2 pipe during that last 33 feet of accent.

When the water reaches the bottom of the pipe it will have to vent that too.

If 1 1/2 inches is not enough then I am counting on the size and mass of the boat to retard the acceleration.

Needless to say, my first accent will not be from 35 feet.

I'm also worried about getting enough air into the tanks to offset the compression on decent. I'm thinking about a couple of valves to allow me to bleed high pressure air directly into the trim tanks.

I have not had the need to do an emergency accent yet. I'm curious what you felt during and after the accent and did you notice the changes in the volume of air you were expelling? And did your BCD rupture?

Thanks
Doug J
www.submarineboat.com

Hi All,

         I had a rather unsettling experience out at Catalina Island this

weekend.  While diving on the back side of the island, looking for lobster,

we were towards the end of our dive at about 35'  we decided to drop down a

bit so I raised my air expel hose from my BC to release some air, but since

this equipment was still somewhat unfamiliar to me I accidentally hit the

air inject button instead !  Which sent me to the surface.  I had injected

enough air so that there was no way I could expel the air in time to make me

go back down.  I think was rising at about the speed of my bubbles and I

breathed out the whole time going up.   It really made me think, in that

situation I really had no way of preventing my accent.  If for  some reason

a valve like that decided to stick on I don't see too many options for

correcting that situation.  I would think an abient sub would have the same

issue.  Any thoughts on a solution to a problem like that?



Brian Cox











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