I refuse to be discouraged, or be told to scrap the hull and start again.
Internal structures are now embedded in up to half an inch of rock-hard mastic.
Ballasting Trials Continue Full size subs have side ballast tanks, either saddle or double hull, so the system should work.
Ref:
http://w3.shorecrest.org/~Lisa_Peck/Physics/All_Projects/photojournal/paul/submarines.html This model's tanks extend down to the effective bottom of the hull, minus the keel ridge, almost the same as in a circular section hull.
The base of the new 35 mm high main 6V 7Ah battery is level with the bottom of the 100 mm deep tanks, as is the Mister.
The R&D stage I am at is determining ballasting for both deep and shallow waterline running.
With tanks empty and main internals added she rode level and fairly stable.
With tanks flooded the dry space beam to o/a length ratio is still better than my destroyer which is very stable.
Please remember the latest bath test was on a completely empty hull, unstable with open vented tanks, but many model warship hulls might be unstable without
any internals or ballast.
Moving almost a Kilo much lower So, we need to transfer a lot of mass to much lower down in the hull.
The new 7Ah battery is 930 gm lighter than the original 10Ah, and 17 mm lower.
The original ship had detachable keel ballast, so 550 gm in lead sheet strips is being trialled underneath the keel ridge.
Around 400 gm of lead shot is also being added inside the keel spaces.
Together this almost a Kilo of mass transfer should generate much greater righting moment at between 60 mm and 100 mm below the deep waterline.
All other mass items are centred well below both waterlines.
There is now nothing of significant mass in the top 60 mm of each compartment, which is vastly more than in my surface warships.