[flyingfrizzle]

remember you want your boat to be able to flex some when in ruff conditions. A lot of people will over build and get a boat to the point it cant flex which creates hard spots sometimes. I would want to be able to spray off the trash off the top of the tank or make it where it could drain naturally and not hold water around it. On the bulk heads I do, I cut out notches or half rounds near the keel to allow water to drain from front to rear of the bilge area to drain. Looks like you have a PVC pipe glassed in to allow the front to drain to the rear but what ends up in the tank cavity wont drain out. I would do a small void on the rear bulkhead only so that the water in the front wont enter the tank area threw the front bulk head but what builds up (it will get in there somehow) will be able to exit the rear one. If you build both high and don't have a way for them to drain they will just end up holding water around the tank. You want air flow around it and for it to drain and dry. Most bulkheads Carl originally put in these boats had little glass on them and were not super strong the way they were installed. If the deck is done right it should not need support from stringer to stringer. That's my 2 cents, You would think if sealed off you wouldn't get water in there they way you have it but I haven't seen one yet that hasn't found water into it somehow.