[PSUBS-MAILIST] Trustworthy launch

[Jon Wallace]

You'll need to definitively determine if the ballast tanks are venting 
all the way or not.  Have a diver do a visual check. Assuming the tanks 
are venting properly there's nothing wrong, you just haven't added 
enough ballast.  It sounds like you need to add weight equal to that of 
the two divers to get you where you want to be.  My rough calculation of 
the K350 hull, conning tower, and battery pod 1-ATM shells show a 
displacement of 3900 pounds and buoyancy equal to 2429 pounds.  Now you 
have to subtract the weight of all interior parts (ribs, welds, 
batteries, equipment) and then calculate the buoyancy of any outside 
parts (lift rings, valves, hangers, etc) most of which will probably be 
negative and deduct from total buoyancy.  Everything matters so it can 
be time consuming.

The alternative is to do just what you have done, put it in for a water 
test and add weight until it is close to neutral.  The 600 has four 
LARGE lead weights formed to the shape of the hull placed between 
various ribs.  I estimate the total to be close to 300 pounds so the 
fact that you had to add as much weight does not surprise me.

Jon


On 9/15/2013 11:19 AM, swaters wrote:
> Hey guys. I did the first dive in trustworthy. The boat is bone dry 
> with no leaks or even weeping after being in the water for three 
> hours. I did have a few electrical problems due to not getting the 
> grounding bolt area clean enough of epoxy paint, but that is a easy 
> fix. A problem I had was not weighing enough. It was me and a buddy we 
> both weigh 175 pounds or so. The two drop weights are 250 pounds total 
> (same as kitteredge). I ended up putting 100 pounds of lifting 
> weights, about 200 pounds of old jacks and it still wouldn't go down. 
> I had the safty dives stand on it and it went down. After scrathing my 
> head for a while I decided the scuba tanks on the outside which had 
> 100 pounds negative boancy now is close to 0 boyancy so that makes due 
> for a little, of the extra floatation. But what about the extra weight 
> of the jacks and the divers? The only thing I can think of is the 
> tanks were not venting well. I notice they got hydro locked way to 
> easy. It seems like the 1/2 " line is way to small. So the only thing 
> I can figure out is maybe the ballest tanks were not venting all the 
> way. Everything about my sub is built just like the blue prints so 
> that is the only thing I can think of about it being to bouant. Any 
> thoughts?
> Thanks,
> Scott Waters
>
>
>
>
> Sent from my U.S. Cellular© Smartphone
>
>
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