SUBSIM Radio Room Forums - 'Hovering' Uboat is achievable ??

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- - 'Hovering' Uboat is achievable ?? (https://www.subsim.com/radioroom/showthread.php?t=201357)

Quote:

What I really interested in is when a calm sea prevails in SH3, to 'hang' in one position with no power for hours, listening on the hydrophone which should have a range beyond the horizon in such conditions, coming up when more oxygen is needed. Maybe this can be modded, with a basic minimal power drain on the batteries. This in effect would be a perfect ASW avoidance trick while waiting for something to appear - and even better for anti-ASW in perfect conditions.

But you don't need perfect balance to achieve that in a real submarine. If you get buoyancy close enough and trim on the heavy side, the result will be a very small sinking rate, so that you might spend hours to actually sink, say, 100 metres. Then when you are there you just add a bit of compressed air and there you go up again at slow rate. You can hover slowly for longer than your Oxygen supply will last ...

The problem is doing that at periscope depth, because the extension of the periscope is limited and near the surface there are many turbulences and disturbances, so you would need to do many more corrections.

Quote:

It is my understanding that once you have negative buoyancy the sinking rate is going to increase as the hull gets compressed more and more as depth increases, creating a positive feedback loop. That is to be avoided, for safety reasons.
Normal procedure at least as far as I know, is that once you are below surface you compensate (emptying the negative tank or such) to achieve neutral/slighty positive buoyancy and keep depth dynamically.

From US Navy experience, it is possible to float at a specific depth without using pumps, etc., but that depth is typically not periscope depth. It will also vary (as stated before) by local oceanic conditions (which do change).

I felt that the NYGM model was very close, but I felt that being able to model a depth at which the ship could float (i.e. 50m or so) should be realistic.

I can't find the article right now, but I remember seeing this on the internet outside the USN, layer anchoring or some such.

Anyrate, check out thermal layer ocean on the google

I've done a bit of 'data manipulation' in the ..\data\Zones.cfg file.

NYGM HummingBird

[PumpsXXI]
Multiplier=1.0
;Flotability=0.15 ->> Original value
Flotability=0.005 ->> change this value
.
.
.

Changing the Flotability to the above value I got the sub to sink about 50m over 12 hours which is sort of acceptable. The funny thing is that the sink rate is not consistent, and will even rise a little at arbitrary depths, but the sub generally sinks, albeit much slower. A speed of 1 knot will keep you more or less at constant depth at 245m, but you'll need two knots or more to bring the sub up.
Still testing and playing around...
:arrgh!:

Cool! I like that. :sunny: