Ok, now for some theory here behind trimming this big 1/72 Seawolf. In normal cases for sub trimming the assembler usually is given a purpose sized wtc designed specifically for that particular model or can modify the ballast tank size to what is needed. The latter is accomplished by filling the ballast tank, then adding weight to the boat until it sinks to a proper submerged level. The ballast tank size can then be determined by adding enough foam below the surfaced water line so that the sub surfaces properly to that line....the volume of the ballast tank needed is the volume of the foam used. Now, seeing as my Seawolf is a brand new boat about to hit the market, the ballast tank volume is an unknown commodity. Because of this, David has supplied me with a purposely over-sized ballast tanked Subdriver (9" x 3.25" id) so we can sink and float this baby.
So, the first dunk without foam or weights added and an empty ballast tank showed a very heavy stern and very light bow - full ballast tank sank the boat to the bottom like a rock. This tells me that the ballast tank is more than sufficient for surfacing. This also tells me there isn't enough buoyancy supplied by the permanent dry spaces to lift the boat to a proper submerged condition. This means foam will have to added above surfaced water line
For stability, 16 oz of fishing sinkers were hot-melted to the bottom of the hull...12 oz directly under the ballast tank and 4 right in the bow to balance that heavy rear end. A fair amount of foam was placed where convenient in the stern to provide some lift.
Another dunk showing my stern to have a little too much foam
Once proper surface level is achieved (backwards methodology I know) I added bunch of foam to the top of the deck and removed small pieces enough to the get the boat to submerge to its proper level. The foam is shifted slightly from one side to another to achieve a zero bubble. This would be to have the top cap of the sail stick out out the water and have the boat sit level under the water.
With this trim achieved, I can go install all that foam and dunk the boat again for some further fine tuning. For those interested I posted a ton more pictures on the HMK Facebook site (check my signature). Any questions and comments are welcome too, as I'm sure I left a lot out here...