Where is the rot in the plywood in your gunter Potter? You have me confused (my natural state, I fear). Is it in the wood surrounding the centerboard trunk? The centerboard trunk on my gunter, #363, has a thin fiberglass liner which is surrounded by plywood. Yours is probably more like Harry Gordon's, considering how close your boat's hull number is to his.
By the way, no matter what Harry Gordon may say, he is the expert on the first generation gunter Potters (the ones with no sliding hatch) and probably all gunter rigged Potters. His knowledge is encyclopedic.
Is the rot in the plywood bulkhead between the front of the lazarette and the area under the cockpit? In my Potter the area under the cockpit is completely inaccessible unless you cut into the bulkhead between the lazarette and the area under the cockpit. I cut into that bulkhead in my Potter, cutting it out about two inches in from where it is bonded into the boat. I then saturated it all with WEST epoxy and glued a flange onto the piece that I cut out , so that I could screw it back into the place where it had been.
Is there a hole in the fiberglass cover for the centerboard trunk in the cockpit? There shouldn't be any plywood exposed in the cockpit except for the vertical hatch (yours is full-length, I believe, from the top of the back of the cabin to the cockpit floor).
Is the rot in the 1/4" plywood that is bonded to the inside of the hull, that extends from just ahead of the transom to under the v-berth in the cabin? If that's where it is, and there are not large amounts of rot (and if you can get at it to work on it) filling small holes with Marine-Tex or larger holes with plywood would probably do the job.
The most common place for there to be rot in the wood in old Potters is in the bulkhead that goes across the boat in the cabin at the front end of the centerboard trunk, that holds the after end of the permanent part of the v-berth. The center part of the after edge of the v-berth also develops rot, as do the front ends of the plywood sides of the centerboard trunk. This is partially due to water leaking in around the hole in the cabin top where the mast goes through and partially due to water coming in through the front end of the centerboard trunk (the slot in the front of the trunk goes five inches below the centerboard arm, when the board is up).
I have had to fix rot in all of the above places in my Potter, and a few others besides. If you can tell me where the rot is in your boat, maybe Harry or I can make some suggestions as to what you might do.
Regards
Tom Grimes
P-14 #363 Far Horizon
Muncie, Indiana
PS---To everyone out on the Potter web---
I would normally have attempted to answer Eric's questions directly to him, but Dennis has requested that we answer questions on the net---that's the reason for this large posting. The number of people who might be interested in this is rather limited, though---gunter Potters all have hull numbers between 151 and about 450, and Mark I's go from 450 or so to 599. The Mark II's started with hull number 600 and to the best of my knowledge don't have any plywood in them. I don't think that I have over two dozen names of owners of gunter Potters--the vast majority of Potter owners have either P-15 Mark II's or P-18/19's. Unless anyone is interested in reading my interminable verbiage of the subject, I will henceforth not post matters related only to gunters on the web.
Tom