I´m sure many would disagree, but this is a problem that has been going on since the fin keel became fashionable .
I'll be one of those who disagree.
There were many, many thousands of fin keel boats that sailed the oceans of the world and yet the loss of keels was almost unknown until about '85, when fin keel roots started to generally become smaller.
Try to find an instance of a lost fin keel in a boat designed before the late '70s or 1980s. I can find mention of only one in my very extensive library; the 30 foot Van de Stadt design "Pioneer", which was struck by a whale in the '71 Cape to Rio. She took 20 minutes to sink and the crew got the time to get into a raft and be found by a freighter well of its course. It appears from the name and LOA that this boat would have been one of the many hundreds of Pioneer 9s that were made. Matuku was also lost after a whale strike between NZ and Australia around December '67, but I don't know if she suffered keel damage. Snow White was lost after a while strike between Suva and NZ in 1979 but since we know that whale strikes can sink conventional cruising boats (as people like the Baileys found out) whether these issues are an example of a "problem" with fin keelers is very much open to debate.
So known cases of sinking due to keel loss in the early fin keel days were rare - just one, and that was due to a whale. It also appears that even if the crewed offshore racing boats that vanished without trace are ascribed to fin keel problems, there is still zero evidence of a significant problem. The number of crewed offshore racing monohull yachts designed before '77 that vanished on deliveries or races was minute. There were two in an early '50s race in NZ (Wellington-Christchurch); the Mauric one tonner Airel in the 'Med about '76; the Spencer design Sequoiah (?) between Hobart and NZ about '84 (?); and the heavy displacement Finnisterre-style S&S "Revenoc" off the east coast of the USA in the late '50s.
That's about all I can find any info about, from searches in my extensive library and on-line databases, plus going through just about every mag in the national maritime museum library. Sure, some may have been missed but the losses that did occur were quite well publicised so there is no reason to think that many other fin keel offshore racers vanished without trace, nor that their losses were due to keel loss.
Only two of the boats that vanished (Sequoiah and Airel) were fin keelers; the two boats in the Christchurch race would almost certainly have been long keelers; Revenoc was a keel/centreboarder. While this is a very scanty database, it certainly does NOT show that losing fins was a significant problem or that they are more dangerous that other types. I know of at least one full-keel boat, to a design and builder that has a good popular reputation. that suffered major cracking around much of the bilge area around the full keel, so it's not as if they are immune to such issues.
The facts appear to be that keel loss was basically unknown in the days of bigger fin keels, as were used in S&S/Carter/Peterson/Holland type boats and by people such as Farr until about '78. Given that the boom in offshore racing peaked in the "early to mid fin keel" era ('70s to mid '80s), it appears that the loss rate of fin keel boats was dramatically LOWER than that of earlier eras.
None of the above should be read as saying that we have not had a problem in more recent years - IMHO the current loss of keels (especially in canters) is ridiculous and rating rules (which are fairly easy to change) should be changed to ensure that solutions, which could perhaps be as easy as longer keel roots, are found.
