Water Tanks below the aft Cabin Sole

During the demo phase I remove 2 large 75 gallon tanks from the lazarette and 2 smaller 35 gallon tanks from under the bunk. My plan is to replace them with built in fiberglass tanks between the existing stringers under the aft cabin sole. This will accomplish 3 things (1) free up space, there will be no lazarette in the new design (2) lower the CG a little which will help compensate for the added weight of the sundeck roof and (3) seal off spaces under the cabin sole that are otherwise inaccessible to be cleaned. When I am done all of the spaces under the aft cabin sole will be either tanks or accessible via lift up hatches or gratings in the hanging lockers. The interior of each tank will be sealed with white food grade epoxy paint. I plan to also paint all of the remaining exposed hull area with the same paint.

There will be 4 tanks; one lower and one upper tank in the center line space and one tank to both port and starboard.

 Here you can see the port tank with the baffles glassed in.
the stringer which forms the right "wall of the tank is the new stringer. I ground down the existing glass and laid 2 layers of 18 oz roving/1.5 oz. mat combination. The new stringer received 4 layers.
The baffles are made from pieces of the original glass work I cut off the bad stringer. I am trying to recycle all the fiberglass parts I cut out of the boat. I see no reason to throw away good glass work and then have to buy more materials to replace it.
As you can see the outboard tanks will be pretty shallow at the aft end. My intent is to close off spaces that would otherwise have be cleaned. There will be an 8" X 12" access plate in the top for each space between the baffles. I also need to cut more holes in them.

Here is shot of the lower center line tank showing the forward end.  The dark line you see snaking down the starboard side is a 1" tube I glassed in to act as a drain from the space aft of the tanks where the rudder stuffing box(read leak) is located.

There is a small problem here, the tank will be taller than the bolts for the stuffing box.










So I built a 2nd wall 5 inches aft and down to a depth below the bolts.You can see the shaft tube going through it.

View from aft looking forward. The tank extends under the "cutout" piece to a wall in line with the teak block. Again closing off space that I would not be able to reach to clean. this tank is about 3 feet deep at the forward end.

Here are two views of the upper center line tank in progress. I built it using 1/2" Dura Ply. I then covered it inside and out with 2 layers of 24 oz. biax. The corners and joint to the stringer is reinforced with 3 layers of 24 oz biax tape.
This tank rises up above the cabin sole to occupy lost space under the bunk. There will be one baffle in each tank.



Here is how the baffle for the upper tank started out. It is a piece of the aft cabin side. The plywood was "bonded" to the glass work after it had cured using a bondo type material. The bond was not very complete, so I chose to remove the plywood and grind the bondo off.

Same piece after removing the plywood and grinding all the paint off the outside and bondo off the inside.

 

 So that about catches me up to where we are now. I have done some a lot of work in the engine room removing a complete mess of wiring and the bulkhead between the engine room and the port fuel tank. Not quite sure why they put it in. Again creating spaces that can not be accessed to do cleaning and maintenance. I can now see that the top of the tank is rusty... Oh boy more work.