[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PSUBS-MAILIST] Escape from a K250 at 200 ft




Hugh Fulton created a "flooding" spreadsheet calculator back in early May of this year.  I just checked it and the results for a K-250 type sub at 200 feet with one 2-inch flood valve comes out to total flood in 50 seconds.  With one 1-inch valve that time is slowed to 200 seconds, and with a 3/4 inch valve the time is 355 seconds.

I didn't have time to post the spreadsheet before the convention but will get to it this week.

Jon



On 8/24/2010 4:06 AM, Alan James wrote:
Hi all,
I've put some facts & figures together re flooding a K250 at 200 ft.
Firstly, sorry I move between metric & imperial. I was brought up on
imperial then N.Z. moved to metric. The metric system is great for these
soughts of calculations.
The first assumption is that the hull & hatch area displaces 1,100 liters.
The hatch 100 liters & the hull 1000 liters.
The flow figures through a 2" pipe come from table 2 on this link. It was the best I could find.
These figures are approximations as the flow rate changes all the time. Also I'm not
taking into account how many or how fat the occupants are.
To fill to half way with the 2" valve at 100 psi the water will be coming in at 384 gallons per minute.
It will fill the 550 liters (132 gallons) in about 20 seconds. The air in the hull will be compressed
to half its size & will be an equivalent pressure (14.7 psi) as at 33 ft.
To fill the hull from 1/2 to 2/3 the flow pressure will be between 85 psi & 70 psi. About 340 gpm.
The volume to be filled is 183 liters ( 48 gallons ).This will take 8 &1/2 seconds. In terms of internal
pressure you have just gone from 14.7 to 29.2 psi wich is the same as diving from 33 ft to 66 ft in
8&1/2 seconds.
To fill the hull to 3/4 the pressure will be from 70 to 55 psi about 300 gpm.
The volume to be filled is 92 liters ( 24 gallons ). This will take about 5 seconds. Again this is
equivalent to going down another 33 ft. to 99 ft.
Am being kicked off the computer for the night so will leave it there.
But that is flooding so fast, I'd want to have my hand on the valve as at that rate you'd blow
your ear drums for sure. It's best to equalize your ears before they start feeling pain & in this
instance you can't reverse the pressure like while diving, by ascending.
These figures are open for correction.
Regards Alan