[TorpX]

Ok, the internet just ate my post, so this is going to be the short version.

You will run Decks Awash at 27 feet but will only have a maximum speed of 8 knots for any engine setting above 2/3. There is no increase in speed above 2/3 settings

I am trying to determine why ISP limits the Decks Awash speed to only 8 knots for any setting above 2/3.

First, try going to GQ. The engine room compartment Ef is important here. Having better crew should help some.

If you are deep enough to fully submerge your hull, you are essentially a submerged submarine. The only advantage you retain, propulsion wise, is being able to run the diesels. If you are too deep to do that, you might as well be fully submerged.

Your exact speed will likely depend on your exact depth, and crew Ef. Don't expect much better than your max. submerged speed, if your hull is under.

I am hoping TOPRX can help shed some light on this for me so we can get a consistent speed out of decks awash no matter which of the mods are running.

??

You can't expect the same results with ISP as with other mods, as it changes propulsion at a basic level. Otherwise, there would be little point in using it.