drop weights, buoyancy control and ascent rate.

[louis omersa <grubby@server.northernnet.com>]

Hello:  

I have a short story to tell the group about a situation that happened to me
while using my semi-dry. The start of the dive went well and after a time I
decided to set it down on the bottom, I was in about 25 feet of water. As I
went to the bottom, a diver friend followed me down, a good person to have
around when your new at the game. The diver swam around the sub looking it
over and we waved to each other. After a short time on the bottom, I decided
to lift off the bottom and continue on with the dive. I put air into the
canopy and was waiting to lift off the bottom but nothing was happening.
With hand signals to the diver I had him check to see if I was caught on
something, he found no problem. I then put more air into the canopy for more
lift, in minute I was on my way to the surface, with an ascent rate way out
of control. With the control system I had, I tried to bleed off air in the
canopy on the way up but the bleed rate was to low. I looked up and saw the
surface coming and an instant later I was on the surface. Some people on
shore told me they saw it come completely out of the water. The next thing I
knew I was going under again and then poping back to its surface position.
That is a ride I don't ever want to take again. I guess the point I want to
get across is, You can do all the math caculations on land you want for drop
weights and ascent rate but in the end, will it bring you to the surface
safely. In the first dives you do with your Psub, in shallow water, see if
your safety systems work as planned. When I did the first dives with my
K-250 , one of the first things we did was to see if the emegency drop would
bring the unit to the surface. I put the K-250 right down in the mud, I was
in 15 feet of water and released the drop tray. The ascent rate was fine but
vedio that was shot, showed very little free board on the conning tower
hatch ring. I calculated I needed two more inches of freebord, so I moved
lead from the sub proper to the drop tray. Think safety in all your planning
for your Psub.


                                                Louis Omersa