We should leave the boat building to boat builders.
Look at the foiling IMOCA's, blank cheque engineering, load cells & alarms everywhere and they still break them.
But without a mandated minimum standard a commercial boat builders incentive to become safer is that they only have to be marginally safer than their competitors, or even just matching them.
The old "to out run a bear, you only have to be faster than your friend".
Imoca boats are pushing the limits of performance as well as the envelope for technology not building entry level cruisers and racer.
Yet, keels are falling off across the spectrum. Old race boats, brand new race boats, old cruisers, new cruisers.
I get that you're passionate about this, and I'm not trying to diminish the work that has already been done.
You're also correct that this is still not an everyday occurrence, but it's happening a little too frequently for such a small community.
BTW, here is Appendix L, the inspection form that is referenced in Section 3.02.
Nope, no strict design standard here...
It has to be built to ISO12215.
It's here: cdn.standards.iteh.ai/samples/55339/7a7b322a16be4c18a230800fc71c8a02/ISO-12215-9-2012.pdf
Ok I hate government regulation but the keel issue is absolutely deadly.
Long ago car manufacturers were forced to consider the inevitability that a certain percentage of cars will have crashes. This lead to energy absorbing subframes side intrusion bars and the like which are actually tested by various bodies worldwide including ancap. This has caught on to the extent that it is newsworthy and a reason to shy away from a car if it doesn't get a five-star rating from these testing bodies. You can of course still buy a low volume AC Cobra; Lotus 7... or similar if you want in the full knowledge that it has no secondary safety.
Similarly it is inevitable that a certain percentage of yachts will run a ground and some of them quite hard and at speed.
How about legislation to the effect that the bottom half of a keel or perhaps even two-thirds needs to be sacrificial in the sense that the bolts holding it on will sheer before the attachment to the hull does? This needs to be in conjunction with a requirement that sufficient ballast remains in the top half or third of the keel so that the boat will slowly right or at least not turn turtle. This requirement could easily be tested by ancap style tests which would become compulsory for let's say manufacturers producing 20 or more of a particular design. If the sacrificial portion worked they wouldn't even have to sacrifice a whole boat just the bottom of the keel. This would force people who run hard aground (charterers and charter companies this means you) to do something about it as they couldn't just forget about it and eventually on -sell the boat to some hapless unsuspecting soul.
It would also probably put paid to ridiculously high aspect ratio keels with bulbs on the bottom as well as dingy style hull profiles (good riddance). Those who wish to risk their lives with one off designs just to win races could still do so with their one designs but everyone would be aware that it had no ancap style safety rating.
The risk with a catamaran is that you rip the bottom out of the boat if you run aground as the bottom of even very large cats has nowhere near the strength of a keel yacht as it is not designed to support a keel. Cat sailors are also used to taking their boats into quite shallow water. Manufacturers have recognised this issue and many production cats have sacrificial keels comprising foam with a light layer of fiberglass thereover sitting into pockets in the bottom of the hulls. The basic concept of a sacrificial keel is therefore not new although it has to my knowledge never been proposed in relation to a keel yacht which is a totally different proposition.
Jules - I hadn't thought of that idea for monos, but I certainly used it on my cat. I made the cedar/glass daggerboards and cut off the bottom 30cm and then glued it straight back on with epoxy glue, no glass.
For 23 years all was well and good, until last year I came into Swansea bar and my self made autopilot drive hub fixing fell off. I should have been hand steering over the calm bar but didn't for a few dumb reasons. Anyway, we went off course and hit a rock with the port daggerboard. There was an almighty bang, and then boat kept on turning away from the rocks under (now) hand steering.
After telling myself off and giving myself a few uppercuts for being an absolute idiot, I anchored and dived on the boat. The board was a little wedged but there was no damage to the hull and the bottom 30cm was gone.
No real worries, I took the board home (where I had a spare tip from when I built the boards decades before) and glued on an new tip. All good now. So a sacrificial tip can save high aspect foils from causing massive damage to the structure. Getting it to work on a ballasted boat is trickier. Lots of cat sailors don't do the sacrificial tips idea even though it saved my bacon.
As for sacrificial cat keels - I don't get them. A lot of cats with these keels can't sit on their keels on the sand or in some lagoon. What is the point of owning a cat if you can't sit on the hard at low tide? A truly awful idea, to go past Percy lagoon, Hill inlet, Zoe Creek, Leekes Creek and not be able to dry out would be terrible. I don't get them at all and think they are a catamaran design travesty. Drying out is a cat super power and not being able to sit on the hard negates a huge reason for buying one.
cheers
Phil
And then there's this guy on a yachting Facebook page who has just bought a boat and asks if he should be concerned. One bolt is actually snapped off inside the nut!
I am not a metallurgist but I have done a smattering of engineering for my own boats.
In most structures there is a critical crack length, a length at which a crack will be self perpetuating when a load is applied. We can see this with a small rip in a kite. As long as it is not too long we are usually fine, but when it gets too big or the load increases then the whole kite rips in half.
When designers start to use higher and higher stress steel in their designs the critical crack length drops. It is a major problem in surveying structures if the critical crack length is too small for a user to easily observe. You really want the critical crack length to be something that paint can't cover, or that is obvious when the boat is antifouled. It is hard to find a material that is very stiff, very strong, very tough (good at crack stopping and coping with stress concentrations) and not very very expensive. In multis I have had problems with lightweight carbon laminates - they hold fine until they just explode - whereas an E glass or timber structure can deflect, groan and make cracking noises without going to ultimate failure straightaway. It suits my style of boat ownership better. If the critical crack length is very small, you may not be able to blame the owner for a keel failure, even if they gave the keel a good going over last time it was antifouled. (Another good reason for lower stress keel roots - you can see when they are becoming a problem and they fail slower)
cheers
Phil
Or some other methods of being able to identify that a keel has been over stressed.
I just think about all the ways we have off being able to identify when a vehicle has been in a crash, or if it has serious safety issues.
Just think of the value difference between a 2nd hand car and a racing yacht.
And yet it is so hard to be confident in the material state of a vessel that may be 10 times the value of the vehicle I transport my entire family in, every day.
Thats why it would be good to have a more updated global standards body like ABS or Lloyds register of shipping yacht scantling standards that covers all the modern methods of construction. It levels the playing field if everyone has to build to the same scantling standards.
Its incredible how hard it is to get scantling or structural standard design details from modern mass production yacht makers. I also wonder why even today its such a struggle to find the Limit of positive stability data from manufacturers. In the absence of a certification body its a bit much just expecting people to accept "trust us" It also clear that the so called CE standards are not working when Beneteau keels are failing on a regular basis!