Bolt on keels on a bluewater cruiser ?

Chris 249 said..








Fair call, there was one boat in 1984; the next one was Drum (1985) and then there was two more in the '80s.

The list doesn't include Planet X, a Goddard half tonner that lost its keel in 1989 (IIRC) off the Gold Coast after what was alleged to be a weld failure on the MME elliptical keel.

The 1984 one I didn't know about and it may not have been in earlier reports. It was a Castro Jeanneau Sunfast in the Figaro which must have been one of the very limited-edition Sunfast half tonners like Balthazar (IIRC) which had a high aspect keel with no bulb and was not an elliptical. The cause of keel loss is unknown so there is no reason to assume it was keel bolt failure. The Sunfast 30 was a leading-edge stripped out IOR machine with the emphasis on light wind performance.

After 1990, when keels changed, the toll becomes stupidly high IMHO. But the physics of a bulbed high-aspect short-root narrow-section keel are very different to those of the standard pre '85 keel, and the latter just do not come off.

I'm morbidly interested in the danger of sailing since my father was killed sailing when I was three. My collection of sailing magazines dates back to 1893 (yes, 1893 not 1983) and they do not include reports of keels falling off until that 1984 Sunfast one.

As an actual risk, it's vanishingly small.

kjman55 said..
About 15 years ago I did the inquest ( and the subsequent suit) into the deaths of 2 women when the bolt on keel of Rising Farrster fell off about 8 ks off Ballina in Force 1-2 conditions late at night. The boat sank without any prior warning in a matter, literally, of seconds, according to the survivors. I think 4 or 5 occupants were asleep, and 2 did not have time to get out. One of the dead was an SAS member, so they were fit! No one had time to get life jackets and the survivors had to swim maybe 15ks ( with currents) to get to shore. They were all fit and young.
The keel failed , the Coroner found, because of inadequate keel washers,compared to the floor frames as built which caused a series of calamatous failures , ultimately leading to a full peeling of the laminate as the keel,came off. I will not go into any questions of fault here, or cast any aspersions on anyone, but raise it only to show that bolt on keels rely upon a number of critical factors and that failure may be lurking unknown and unwarned without any visible signs. This keel had been flexing the hull imperceptibly in way of the floor frames, till it reached a critical failure mode in calm conditions. I no longer have the brief obviously, but I seem to recall that the failure actually sheered at least one of the bolts which was solidly anchored through a frame, and that it was a stress overload failure , not a corrosion fracture. Of course a Farr 40 is not a particularly big boat nor is the keel particularly heavy compared to some modern boats utilizing bolt on keels.
Modern composite construction often leaves little choice but to utilise a bolt on keel. Luckily failures are rare, but when they happen are catestrophic. Had there been any sea running when Rising Farrster was lost, all would surely have perished that far out.
i do not know what the answer is other than significant over-engineering. Andy Dovell said that it was then usual to allow ( this from my fading memory) well over a 200% margin of safety in design . I do apologise to Andy if my memory is wrong. The problem seems to me that issues can be lurking within a composite structure that looks perfect upon inspection, the latent failure being well within the structure. Maybe x ray-ing as they do with welds?? I dont know if that is even possible.
Just my 2 cents.
Cheers Keith.

kjman55 said..
About 15 years ago I did the inquest ( and the subsequent suit) into the deaths of 2 women when the bolt on keel of Rising Farrster fell off about 8 ks off Ballina in Force 1-2 conditions late at night. The boat sank without any prior warning in a matter, literally, of seconds, according to the survivors. I think 4 or 5 occupants were asleep, and 2 did not have time to get out. One of the dead was an SAS member, so they were fit! No one had time to get life jackets and the survivors had to swim maybe 15ks ( with currents) to get to shore. They were all fit and young.
The keel failed , the Coroner found, because of inadequate keel washers,compared to the floor frames as built which caused a series of calamatous failures , ultimately leading to a full peeling of the laminate as the keel,came off. I will not go into any questions of fault here, or cast any aspersions on anyone, but raise it only to show that bolt on keels rely upon a number of critical factors and that failure may be lurking unknown and unwarned without any visible signs. This keel had been flexing the hull imperceptibly in way of the floor frames, till it reached a critical failure mode in calm conditions. I no longer have the brief obviously, but I seem to recall that the failure actually sheered at least one of the bolts which was solidly anchored through a frame, and that it was a stress overload failure , not a corrosion fracture. Of course a Farr 40 is not a particularly big boat nor is the keel particularly heavy compared to some modern boats utilizing bolt on keels.
Modern composite construction often leaves little choice but to utilise a bolt on keel. Luckily failures are rare, but when they happen are catestrophic. Had there been any sea running when Rising Farrster was lost, all would surely have perished that far out.
i do not know what the answer is other than significant over-engineering. Andy Dovell said that it was then usual to allow ( this from my fading memory) well over a 200% margin of safety in design . I do apologise to Andy if my memory is wrong. The problem seems to me that issues can be lurking within a composite structure that looks perfect upon inspection, the latent failure being well within the structure. Maybe x ray-ing as they do with welds?? I dont know if that is even possible.
Just my 2 cents.
Cheers Keith.