Boats are truly "holes in the water in which we pour money"! I am sure you can substitute other nouns here but down here in Florida it tends to involve the water. The Blue Water Open had myself and 2 fishing buddies 30 miles out in the Atlantic looking for Dolphin, Amberjack, etc to get us on the leader board. Though we got on the board and made a few bucks, the run back through increasing seas cracked the side of my fuel tank so this created an "opportunity". This is what us boating types do to spend ever more money on this disease... 

One flaw in the design of my old Mako is the weak "hole shot" ability of the boat as her CG is too far aft combined with a dive platform extension. To non-boaters, hole shot is the ability to quickly lift the stern of the boat up as the boat accelerates on to a plane. The 143 gallon fuel tank ran about 8' fore and aft so I figured the solution was switch to  2 tanks so I could leave the the rear tank empty most of the time moving the CG far forward. So project started up with a little bit of "disassembly required". It sure was handy to have a buddy with a crane to lift off the console and deck plate...

Then pop out the old tank and prep the hull for something better!

Now the hard part - the old tank tapered vertically from front to back as does the large hole it came out of so not just a simple coffin shape to slice into pieces like a loaf of bread. Time to fire up the CAD system and do some thinking. First model the original tank. I figured this would give me that "master model" I would need to fit the new double tanks into the same volumetric space...

Then, I just sliced and diced the main volume into 2 new tank derivatives which preserved the weird shape. I had to also model the deck cover plate as the new dual tank system meant I will have to cut and fiberglass in new inspection covers. Just some more "scope creep" most of you are familiar with...

I then whipped up the needed drawings and headed off to my friendly neighborhood fuel tank builder with checkbook in hand. I'll blog again once I get my fancy new tanks home!