P-15 Under the Cabin Liner Floor

By

Bruce McCreary

Owner of P-15 #867

Here's a photo of what's under your cabin floor, and what supports the mast. I always wondered, and thought you might, too. You can see I've overcome my fears of butchering my Potter.

I cut holes down to the hull in order to secure 4 to 5 gallon containers of alcohol (the fuel for my converted outboard) low and along the centerline to enhance stability and protect the cabin from damage in case of a knock down. This results in 160 lbs of ballast fairly low and forward.

Underneath the massive layer of flotation foam, I found an edgewise piece of 3/8" plywood that supports the mast. It bridges between two bulkheads (over 3 feet apart), and it has about 2" gap below it to the keel (to keep the ply from rotting. When the rig is tensioned, this flexes downwards about 1/4".

While the P15 has perhaps the best reputation for durability and long life of any small boat, I have always noticed that the rig was pretty flexible in high winds. So I epoxied in a piece of foot long, 2" x 1/2" thick GR-10 board (epoxy-glass) between the bottom of this plywood support and the keel centered directly under the mast support.

I can't say how this will affect rig stiffness, but will let you know.

I used foam in a can under plastic wrapped fuel containers to mold supports on the hull for the containers. It then cut away the excess to keep the bilge clear.

Blue hold down straps for each gallon container are fastened to hull on the outside via epoxied aluminum plates and in the center line by bolt through to the plywood mast support beam.

Later this summer I hope to make liners for these holes and lids for when I'm not carrying the outboard and fuel.

In the category of boat design dreaming- If I was modifying the P15, I think I'd closed cell foam fill the bilge, and have a removable drain container for the forward chain locker instead of having it drain to the bilge. Then I'd use the extra volume under the cabin floor for storage lockers. Four hatches could provide access to this new huge storage space. (The new raised floor could be raised a couple inches to increase this space.)

I'd also think about an offset to the centerboard of 6-9" like the Sanibel (sp?) to have a small but deep footwell right to the keel right just inside the cabin door. This would make using the portapotty less of a contortionist's exercise.

Bruce McCreary

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