So, I built the platform for the fuel tank. I'll paint it first before installation. I'll have to strap the tank down at a bit of an angle to place the fill cap on the centerline.
The choice now is between placing the fill cap almost dead center of the foredeck, or just behind the breasthook. Neither is ideal for filling, but it keeps the tank up front and out of the way. It also promotes getting on plane easier I think.
I'm leaning toward placing it behind the breasthook. This will make is easy to fill with pre-mix while it is on the trailer. I don't foresee needing to re-fuel during a days boating activities, since it will hold 13gals at need (I plan on filling to 6gals for average days).
This craft won't be fueling at marinas if I can help it.
Also..., I found Merton's 97% closed-cell pour foam for $75 per two gallon kit. It's USCG approved and will yield 9 cubic feet. At 63lbs floatation per cubit foot, that'll support 567lbs. I estimated my need at 400lbs with 50HP engine, fuel weight, battery, hardware, steering, etc.
Does this sound ok, or have I made a drastic miscalculation somewhere?