Red Ranger
Norfolk, VA

The v-berth tank always leaked. The port side saloon tank now leaks.

See https://www.whitbybrewersailboats.com/maintenance-repairs-upgrades-and-additions/42-water-systems-and-tanks/230-water-tank-fun-on-jdv-2. 

The solution seems to involve custom tanks by Dura-Weld.  See https://plasticfabricatedtanks.com. 

Under the saloon floor we have two choices:

Option 1: Follow the Joie de Vivre plan and tear out the old tanks in their entirety. This gains about 4½″ vertically (by 35″ by 72″) which doesn’t seem like much until you consider the tank is only 12″ tall; this is 37.5% gain in volume.

Option 2: Sacrifice some volume and install four new tanks inside the legacy tanks. This involves less destruction and less reconstruction. It sacrifices volume, but lets us drop four tanks through the available hole in the cabin sole, strap them in, connect up tubes and have water.

Under the v-berth, we have similar choices. The tricky part about the v-berth is the tanks are not fiberglass with an aluminum lid. They’re 100% aluminum over some supporting structure. The aluminum could be sitting in a fiberglass shell, or could be sitting on wooden stringers.

I think I want to assemble 5 mini-tanks inside the available volume. Four are wedges, jammed into the fore and aft corners. The remaining one sits over the center ∨ at the aft (deep) end.

The access panel under the v-berth is 21″×21″. The space is 50″ long and expands from 12″ by the anchor locker to 54″ by the forward head.

I think a handful of tanks that are less than 21″×21″ can be dropped into the space and plumbed together with a common filler, common vents and common drains. This will create a system of tanks less than the original volume, but made of of nice, clean, new materials.

I think I can strap each tank to a plywood base and screw the base to the aluminum, minimizing the destruction.

What’s the original volume? 

Yes, that’s calculus. 42¾ gallons. (The formula assumes the 54″×17″ triangle shape is consistent from front to back. I can’t measure the front triangle, but it appears congruent with a 12″ base.)

Five tanks of 4, 4, 6, 6, and 18 gallons gets to 38 gallons of water. It’s better than what we have now, which is an estimated 42¾ gallons of air.

Next Steps? 

Cut the old aluminum lid off the old tank. I think this involves the following:

1. Drill holes into the aluminum tank lid under the v-berth access hole. Use the reciprocating saw (the Dewalt version of a Sawzall) to cut away the tank lid. This will be larger than the original (tiny) access panel on top of the tank, and make some room to work.
2. Slice all the rivets around the outside of the lid. I don’t know if I can reach all of them. This may involve some advanced yoga to get the saw all the way in there. The Dewalt has four blade position alternatives, and this may key to slicing off the rivets. 
3. Cut the lid into pieces and pull them out through the hole. This involves carefully checking clearance to be sure I don’t accidentally saw through something important, like the v-berth itself.
4. See what access we have under the floor to the aft section of the tank. I theorize that there’s an awkward space that — perhaps — can be cut away to allow putting in really handy drains from the aft ends of the three tanks that fill the aft end of the void. A drain that’s at the lowest point (with no pickup) would be handy for priming the water pump.

Once we have access, we can start to make more concrete plans.

1. Measure. Measure. Measure. The size of the forward cabin door and the size of the companionway hatch may constrain the tank sizes. (Scott and Jeanie got a 21″×16″ tank into the saloon, which suggests this may not be a constraint.)
2. Redo all my concept sketches with correct measurements.
3. Get some CAD software and draw the plans for all five tanks. Maybe https://www.shapr3d.com/3d-for/engineering will do what I need.
4. Make cardboard mockups and dry-run the installation to see if this will work.
5. Update the CAD drawings.
6. Order tanks.
7. Order plumbing parts CA wants to replace the filler and vent lines, too. Why not?

Then we can see if I can assemble it all.

I want to do the v-berth first because there’s nothing at stake there. It’s a complete win if this works out.

While the saloon is simpler geometrically, I think it involves a more complex path of destruction to get the old tank lids out.