Hi BigWalleye,

just to be clear, your SHC mod will not work in GWX because the *.zon files of the submarines do not contain the pump. The NYGM slow-sinking mod requires changes to the *.zon files.

Have you tested negative Flotability values in NYGM? I wonder whether this has any impact because an 'empty' should not get 'more empty'.

Regards, LGN1

Negative Flotability values work in NYGM. The equivalent buoyancy is not symmetrical though. A Flotability of -0.15 (positive buoyancy) causes an initial loss of depth of about 2 m per hour from PD. A Flotability of +0.15 (negative buoyancy) causes an initial gain of 10 m per hour, again from PD. Of course, it the modeling is correct, movement in either direction will accelerate over time. Buoyancy is a force acting on the boat. Force equals mass times acceleration. So, for a constant force, the movement will accelerate, changing depth faster and faster until the unbalanced force is resolved.

I don't understand what you mean by

Zero buoyancy does not represent anything being empty. It means that the weight of the boat (including all ballast water it contains) is equal to the weight of the volume of water the boat displaces. When surfaced, the boat will displace a volume of water which weighs more than the boat weighs (again including all ballast water it now contains). But that does not mean that the boat has been emptied of all ballast. Generally, some ballast water is retained in the tanks to keep the boat from bobbing like a cork (unpleasant for those inside). The difference between emptying the negative ballast tank ("Blow negative.") and emptying the safety ballast tank ("Blow safety.") is the difference between a controlled surfacing and an emergency surfacing. Both create positive buoyancy, but blowing safety creates (hopefully!) a lot more. And trimming the boat for positive buoyancy while submerged involves moving some water out of the trim tanks, not out of the main negative buoyancy tank. So there is still plenty to empty when cruising at depth with slight positive buoyancy. All of this is explained well in NAVPERS 16160.

I apologise if this does not answer your question. I am trying to undertand what you meant.

And sadly, Steve, LGN1 is correct. In GWX3, the Flotability parameter has no effect on the boat's ability to hover like a Huey. Took it to 80 m, stopped, and it stayed right there for hours.

Interesting. It doesn't bother me too much, though, as I never stop underwater and use that anyway. It is, however, something that was built into Aces Of The Deep twenty years ago. "Captain, we can't maintain depth without running the pumps!"

Hi BigWalleye,

sorry for the late reply. I was confused by the word 'flotability'. I thought it was connected to 'floodable' and thus, meant that the compartment could be flooded by a certain amount. In this case a negative value was a mystery for me.

Regards, LGN1

Yeah, "flotability" is not in my dictionary, either. And, since it operates in the reverse sense to buoyancy (positive "flotability" makes the boat heavier), it maybe should be called "sinkability.":) Anyway, I hope you didn't feel dissed by my Physics 1 explanation.

Merry Christmas!