Re: [PSUBS-MAILIST] Damage stability & ballast tanks at an angle

[Alex <spm2@nomad.ignorelist.com>]

Jim what is an inverted stack?

I replied to John Wallice's email but I pressed edit and send by mistake
and now the whole thing got erased. Apparently it sent with John's email
address as the sender but I don't think it will go through.

What I was saying was don't large submarines have vertical separators in the
ballast tanks so that they can still work at an angle? I calculated that at 70
degrees of tilt with a ballast tank that is twice as tall as it is wide that
82.5% would be filled with air before air started coming out the hole in the
middle at the bottom. So with a low center of gravity and 70 degrees of tilt
things could be made to work mostly.

Would it help to put a pipe from the bottom hole of the aft ballast tank to the
forward edge of the tank? That way if the submarine was tilted straight down
the pipe would be pointed down and be filled with pressurized air so that no
water could come in to the tank. Without the pipe it could flood the tank up to
half way with water. But I know that the pipe would not help blow an already
flooded ballast tank past 50% if the sub was pointed straight down. It's just an
idea but it's probably not helpful since it is only use full when the
ballast tank already has air in it. Maybe it would be usefull for internal trim
tanks.

I was thinking if there were drop weights on a submarine with one of two
flooded compartments dropping the weights make the center of gravity so much
worse that the sub tilts much more and causes the ballast tanks to be partially
flooded and in this way do more harm than good.

Thanks everyone
Alex

On 18-Apr-2012 kocpnt tds.net
wrote:
> Hi Alec,
> 
> I think you raise some good points! Since I have some personal
> experience in this area, I thought I might comment.
> 
> I have closed all but one hole on the bottom side of my soft tanks.
> The remaining opening is in the center and is an inverted stack to
> minimize burping.
> 
> I found that when out of trim some items were not as securely attached
> internally as they should have been, and they slid to one end
> destabilizing trim.
> 
> Best Regards,
> 
> Jim K
> 
> On 4/17/12, Alex <spm2@nomad.ignorelist.com> wrote:
>> I've been thinking about what happens if you have a water tight
>> bulk head in the middle and the forward or aft compartment floods. Or
>> possibly
>> with 3 compartments with forward or aft flooded.
>>
>> Does the submarine go almost vertical? And the most important part of this
>> is
>> what happens to the external soft ballast tanks. If the tank has a bottom
>> vent
>> in the middle and it becomes vertical, it will only fill up half way with
>> air
>> before it bubbles out.
>>
>> Worst case scenario: Let's say you have a sub with huge ballast tanks on the
>> bow and stern that can surface even if it is fully flooded inside. Let's say
>> that the forward ballast tank is damaged and the forward compartment is
>> flooded. The unflooded aft compartment and stern ballast tank should be
>> enough
>> to surface. But will the stern ballast tank work with the bow pointed way
>> down?
>>
>> Alex
>> --
>> Mailed on 17-Apr-2012.
>>
>>
>>
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> 
> 
> 
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-- 
Mailed on 19-Apr-2012.



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