PS Advisor 10/01/98
Keel Bolt Conundrum
We have owned an Allied 39 for 23 years. She was built in 1970 and among her strengths is an external lead keel. Having creased a coral head or two over the years, I’m sold on it. The only problem we’ve encountered was a small leak in the forward-most keel bolt, which we had replaced many years ago. Although we check the bolts every few years for tightness and visible condition, we feel that it is now time for a “thorough” evaluation: lifting the boat off the keel, removal for magnafluxing or X-raying or possibly just going ahead and replacing them.
That has raised a whole host of questions and issues. I assume this is not an uncommon problem, so here goes:
I know, from having spoken to the original owner, that the keel was originally bedded with 3M 5200. Should I not try to separate the keel from the boat?
What other test can be done in place?
Although the forward-most bolt was straight, might the others be J-shaped and how does one determine this? The builder has long gone out of business.
Where does one get keel bolts?
What other options are available?
Owings Mills, Maryland
We asked Bill Seifert, who has worked for Tartan, TPI and Alden, for his opinion. Here’s what he had to say:
“Stainless steel keel bolts are perfect candidates for crevice corrosion, which happens when stainless is deprived of oxygen (by bedding compound). Unfortunately, the only way to check them is to remove the keel.
“Removing a keel is usually a lot more complicated than backing off the nuts and picking up the hull from the keel. Since stainless nuts are generally used, and most boatbuilders are negligent in the use of anti-galling compounds, there is a strong possibility that some of the nuts will not back off. Usually there is insufficient clearance in a keel sump to get a mechanical nut splitter in place around a stuck nut, so a small cutter must be used in conjunction with a large cold chisel and a sledge hammer to split the nut. Not the most delicate tools to work with in a yacht interior.
“The Tartan 41 keels were bedded with 3M 5200. When we came out with the deeper keel, several owners returned their boats to the factory for a keel retrofit. In all cases, the 5200 held the keel in place with all nuts removed. We finally fabricated a giant wedge attached to one fork of a fork lift truck. This, and a stout knife to cut the 5200, and about a day’s time, separated the keel.
“Most cast-in-place keel bolts are bent to a J shape and are not removable from the keel. If square or rectangular “windows” are visible in the sides of the keel a foot or so down from the hull, the keel bolts are not cast in place and have nuts on the bottom of threaded rod. These are relatively easy to remove and change.
“A frequently used fix for a leaking keel bolt is to remove the nut and washer, then saturate a rope of caulking cotton with 3M 5200 and wrap it tightly around the bolt. Replace the washer and nut, and tighten moderately. By moderately, I mean with a 3/4” drive socket wrench. Tartan used a 4' long pipe to snug 1" diameter keel bolts, and occasionally would break a bolt, or cold flow the lead enough to raise the cast-in-place bolt.
While inspection of keel bolts for crevice corrosion is a great idea, the procedure is very difficult and in the case of a yard doing the work, may cost more than the value of an older vessel. Since lead is used to shield them, X-ray is out. Magnafluxing works well on metal parts which are exposed. While I am a firm believer in prophylactic maintenance, keel bolts are an area I leave alone, except to be sure that bilge saltwater is not left standing over them.”
We also asked Bill about the possibility of cutting windows in the side of the keel to inspect the keel bolts. While this would work, he said the problem is not being able to fill the windows in any way that restores the original strength to the lead casting.
The bottom line seems to be that one ought to leave the keel well enough alone…until trouble is suspected. When that day arrives, the only sure solution is to have a new keel cast. Then you’ll get new keel bolts, which, incidentally, are usually heated along with the lead. If this is not done, the lead, as it cools, tends to shrink away from the keel bolts.
Major keel makers include Mars Metal Company, 4130 Morris Dr., Burlington, Ontario, Canada L7L 5L6; 905/637-3862; I. Broomfield & Son, 14 Lehigh St., Providence, RI 02905; 401/941-7361; and Hanover Metal, PO Box 27155, Baltimore, MD 21230; 410/539-1338.
Unanswered here is the question of how old a boat must be before replacing the keel and keel bolts is considered necessary. Like the hull, rigging and steering system, the keel is one thing you just don’t want to worry about. Comments invited.