Lost or damaged Keels

[TQA]

I came across this list and while I have no idea how complete it is.

http://www.sailing.org/tools/documents/SRSC7diKeelFailuresdatav2-%5B17112%5D.pdf

It makes very chilling reading if you sail a Mini Transat or a canter.

I do not see a Bene but I guess one will appear when the compiler does an update.

 

[KellysEye]

The type is so small it's illegible. Ah you can blow it up.

 

[Sandy]

Looks like racing is the main reason; clearly they are going over the design limits.

 

[jimbaerselman]

Looks like racing is the main reason; clearly they are going over the design limits.

Or the design limits used were not fit for purpose - racing. If this was the case.

The only design case I've seen quoted referred to keel bolts tensile and sheer stregth, and assumed there were two rows of them. The requirement was for "sufficient strength to support the keel horizontally out of the water, plus a safety factor". I don't know whether that's the universal norm

Safety factors typically allow for variations in manufacture or finish. Several in that list included "weld faults" or other manufacturing slips. Others referred to fatigue failures.

All this implies to me that the design case is inadequate to cover risks.

The extreme case is being dumped sideways off a large wave, and landing on your beam in the trough. The impact will burst your windows inwards, and the sudden halt in descent, being transmitted from hull to keel, can create a massive inertia moment if the keel is still out of water as the hull hits.

So, possibly a rough water threat, rather than a racing threat.

Whatever, with the consequences of keel loss normally being inversion - a killer for many below decks - there seem to be sufficient occurrences to suggest the design critieria are not robust enough for the conditions some "ocean worthy" boats face.

 

[Tranona]

Or the design limits used were not fit for purpose - racing. If this was the case.


Whatever, with the consequences of keel loss normally being inversion - a killer for many below decks - there seem to be sufficient occurrences to suggest the design critieria are not robust enough for the conditions some "ocean worthy" boats face.

The point is that racing boats do not have to meet the RCD requirements, and if you look at the causes of failure where they are known it is usually inadequate design, poor construction or not built according to the original design. The types of failures have very little in common with the very small number of production type boats that have experienced failures.

There is clearly room for improvement in some boats, but it is not the epidemic that some would have us believe.