HOW TO PLUG A NEW HOLE
Q: I am putting an outboard on my Grampian 26, and I will be taking out the old Westerbeke diesel. I will need to somehow close off the stern tube (once the prop shaft is removed). Is there a way to do this so that another owner might put an inboard back in if they don’t like the outboard? If I put epoxy into the stern tube to fill the hole, would someone be able to bore through it if they wanted to refit with an inboard?
Rick Kelly, via email@example.com
DON CASEY REPLIES
You can fill the stern tube with epoxy, but because of the risk of a weak bond this will not be the most secure way of sealing it. What really should happen, in addition to or even in lieu of plugging the hole, is to close it on the outside with fiberglass layup. This involves grinding a wide gentle chamfer around the opening, then laying on multiple layers of fiberglass fabric saturated with resin, preferably epoxy for its superior secondary adhesion. Done properly, this simply continues the hull across the old opening, sealing it permanently. There is no need to fill the entire tube; you just want the end closed to the approximate thickness of the hull. As for the possibility of returning this boat to inboard power, that should not present much of a challenge no matter how you close the hole. Both epoxy and fiberglass lay-up are easily bored.
Don Casey has written many books and articles on marine maintenance and repairs
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