Question: I just purchased a used sailboat from a broker and had it surveyed before the purchase. Everything on the survey report was glowing and no real problems were indicated. That all made me feel really good until I noticed what you see in the photo I sent in.

There should be a lock-washer under the nut on this keel bolt, not just a flat washer.

There should be a lock-washer under the nut on this keel bolt, not just a flat washer.



The hex nut in the middle of the picture is on the aft-most stud holding the keel on my new boat. Now I’m not a mechanical genius by any stretch of the imagination but I do notice that there is no lock washer on this stud and nut, nor did I see any on the other keel bolts that are a little harder to access and photograph. Is this OK? Maybe the builder used Loctite or some other compound instead of a lock nut or washer? What’s your take on this? Answer:  I’m on your side. Even if the builder did use a locking compound I’d prefer to see a lock nut or lock washer installed. I doubt that thread-locking was used because in just about every instance I can think of, you will be able to see some trace of the compound around the nut or on the stud threads. It usually shows up as a red, green, or blue tint, depending upon whose compound was used. My advice is to acquire some locknuts (nylock) and install those. They should be torqued on, and the amount of torque will vary depending upon the stud size. The stud in the photo you sent in looks like it's made of mild steel versus stainless steel. Check this out with a magnet. If it’s magnetic, then it is made of mild steel. Depending on the diameter of the stud, the torque value will vary, but typically you are looking at a 9/16” to maybe a 5/8” stud. For typical grade-five hardware (most common for mild steel) the torque would be in the 75-155 ft-lb. range, depending on the specific diameter. Borrow a torque wrench if you can. To get exact torque values, check online at the Engineer's Handbook  for regular steel and Fastenal (PDF file) for stainless and non-ferrous metals.

Written by: Ed Sherman
Ed Sherman is a regular contributor to boats.com, as well as to Professional Boatbuilder and Cruising World, where he previously was electronics editor. He also is the curriculum director for the American Boat and Yacht Council. Previously, Ed was chairman of the Marine Technology Department at the New England Institute of Technology. Ed’s blog posts appear courtesy of his website, EdsBoatTips.