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

["kocpnt tds.net" <kocpnt@tds.net>]

Hi Alec,

The inverted stack is simply a pipe,(in my case a 4" diameter X 8 inch
long S.S. tube),
extending down from the opening at the bottom of the soft tank.

With this method, theoretically the original opening at the bottom of
the tank could be 4 inches out of the water and the actual opening
would still be 4 inches below the water line.

This should go a long way to minimize unintended dumping of the tank.

Best Regards,

Jim K

On 4/19/12, Alex <spm2@nomad.ignorelist.com> wrote:
> 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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>
> --
> Mailed on 19-Apr-2012.
>
>
>
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