The Rot Doctor


Subject: A question (stripped motor mount)
Date: Thu, 22 Jan 2004

Can your product be used on my application - I have had the lag screws which hold my motor mounts into my boat pull out of the stringers. Can I use your product to "glue" the lag bolts back in, or can I fill the holes and re-drill them or simply drive the lag screws back into the holes after they've been filled? Which specific products would you recommend for my problem? Thank you in advance.

Steve R.


Our products are used regularly to fix motor mounts, so yes they can be used to fix your problem. The two products that I would recommend would be CPES™ and Layup & Laminating™ Resin.

As far as exactly what I would do to repair the problem would depend on how much the wood is damaged. If the wood is good and the lag bolt just pulled out you could soak the hole with CPES and then fill with Layup & Laminating Resin and then re-drill the hole. Often, loose motor mounts are an indication of a rotted stringer. If this is the case, you would want to do a little more work. At the very least, you would want to rebuild a 12" section right around the motor mount. This will give the motor mount something strong enough to take the load. If you just repaired the area right around the hole, that small section would most likely pull out with the lag bolt and you would be right back where you started.

If much of the stringer is rotted you would have to decide whether you wanted to repair the whole stringer or just the 12" around the motor mount. Much of the strength of the stringer comes from the box section shape of the fiberglass which covers the wood. So if you don't stress the boat much, the fiberglass alone is probably strong enough, and you could just fix the 12" around the motor mount. If you take the boat offshore and pound it in heavy seas a lot, I would think about repairing the whole stringer, if it is rotted.

Let me know if you have further questions.