Every qualification known to man and the life raft wasn't even loosened yet was still sending txt .

Tragic. Goes to show how quickly things can go wrong.

Despite their training and experience they hadn't really thought through their options. They appear to have had plenty of time to get ready to abandon ship, and then go back to investigating the leak.
Salt water coming in fast should have had most of the crew ready with the life raft and their survival gear.
Some good lessons to be learned from this tragedy. Especially about being prepared for the worst while working/hoping for the best.

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MorningBird said..
Despite their training and experience they hadn't really thought through their options. They appear to have had plenty of time to get ready to abandon ship, and then go back to investigating the leak.
Salt water coming in fast should have had most of the crew ready with the life raft and their survival gear.
Some good lessons to be learned from this tragedy. Especially about being prepared for the worst while working/hoping for the best.

Yes I think the biggest problem we all face is turning head knowledge into actual actions at the appropriate time. When you have a lot of things on your mind at once and when you are with and influenced by other people sometimes you might not prioritise properly.

Of course when sailing on someone else's boat you are at a great disadvantage and placing yourself wholy in the hands of their maintenance schedule. If the boat isn't your own and you haven't owned it for some time you just never know what dangers may be lurking. I would hate being a delivery skipper or crew

I don't think most people would know how to get ready for keel loss on a mono. If the boat sinks normally the liferaft needs to be where it is mounted, if it inverts suddenly it needs to be low on the transom. Even getting it into the cockpit would not help much. As for investigating how the water is getting in, keel bolts would be one area where it would be very hard to work out how the water is getting in, when in a seaway. Catastrophic inversion is incredibly hard to plan for unless you put the raft where the Vendee boats and some catamarans do, where it is much less accessible for a normal sinking. I can't see how one could plan for the keel falling off without getting into the life raft early, the one thing we are all told never to do. I don't place any blame on anyone here but Beneteau. I have no idea how anyone could have done anything better than what the crew did, jump in the liferaft early? Tow it alongside inflated? Have someone hold onto it and possibly lose it over the side? I guess the only thing to learn is that it may be safer to abandon ship if it can be worked out that the keel is wobbling. Maybe we should all take a GoPro on a stick that we can quickly view shots from so that we can pre-emptively abandon a yacht with a wiggly keel. But trying to work out fatigue failure is almost impossible for the best engineers, so asking a crew to understand when to abandon a yacht with a wiggly keel is an impossible task.

Hard to plan for indeed, if the tie down straps on the life raft lid were let go then in theory when the vessel inverts the hydrostatic release mechanism will activate and presto life raft, it could be caught up in the inverted rigging or if the painter wasn't made off It could blow away. The prospect of the crew being knocked unconscious in a sudden inversion I imagine would be likely. Light weight, fin keel boats do sail well but it appears we have reached the economical engineering limit

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woko said..
Hard to plan for indeed, if the tie down straps on the life raft lid were let go then in theory when the vessel inverts the hydrostatic release mechanism will activate and presto life raft, it could be caught up in the inverted rigging or if the painter wasn't made off It could blow away. The prospect of the crew being knocked unconscious in a sudden inversion I imagine would be likely. Light weight, fin keel boats do sail well but it appears we have reached the economical engineering limit

If I'm taking salt water and can't see where it's from in a seaway after a quick check of sea cocks and prop shaft I'm putting my fingers around keel bolts and feeling for movement. And with my life jacket with personal epirb on too.

Anything dodgy going on I'm sleeping in it too.

You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

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woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

I don't build monos, I build cats, so my musings on keel bolts is from the boats I look at.

But fatigue failure of bolts may not give rise to any movement. Loosening off of keel bolts may, but fatigue is a real bastard to determine - we all have had stainless stays just break with no warning. The same could happen with keel bolts - one or two fatigued and broken, but thoroughly bogged into the keelson and then a few loud bangs in succession as the other highly stressed and fatigued bolts let go. Fatigue is something I know only a little of. Reading about the early De Havilland Comet is a very sobering example of people getting killed through fatigue failure. en.wikipedia.org/wiki/De_Havilland_Comet

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julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

If I can't see the keel bolts when I lift the cabin sole I would not own the boat. If the keel bolts are in line single row I would not own the boat, Keel bolts must be double row or if single row alternatively angled as in S&S 34.

Also for through deck bolts dome nuts are the answer.

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julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

Jules does your yacht have keel bolts?
i know it's iron which I was always against until I found out a lead keel bolted on has to be recast to to do the bolts unlike cast you can just screw straight back in .

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MAGNESIUM said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

Jules does your yacht have keel bolts?
i know it's iron which I was always against until I found out a lead keel bolted on has to be recast to to do the bolts unlike cast you can just screw straight back in .

Yep 12 keel bolts in a double row (except for the first and last) with the tops of the staggered bolts and nuts clearly visible under the floorboards in my nice clean dry as a bone bilge which I look at every time I get on the boat.

If they were ever to start leaking salt water I would be hauling out and the keel would be coming off pronto.

I did have a bit of a panic when there was water in there shortly after I bought the boat which thankfully turned out to be a water tank leaking.

As for overhead dome nuts they are certainly better than long jagged bolt ends but they could still smash your skull and I have some which extend through the ceiling panels beneath my life raft on the coach house roof which I'm not too thrilled about.

I'm not too worried about fatigue on my boat and I know that aircraft air frames need replacing and checking all the time because they are quite highly stressed. The reason why I'm not overly worried about fatigue for my keel bolts even though they are probably 39 years old is that there is no hint of hairline cracks in the fairing between the keel and Hull when the boat is pulled out on a travel lift with the keel hanging. I don't think the fairing is flexible to any extent so if there was any movement in the keel bolts I would expect to see a hairline crack. Mine also look sufficiently chunky according to my 68 year trained eyeball/gut feel test. Aircraft frames on the contrary have to be built light as possible (like serious sports/racing yachts) so move around quite a lot and hence are not as overbuilt and fatigue. I'm not a engineer but that is my understanding.
Similar reason why your steel sub floor and firewall car stringers/rails are not going to fatigue and snap (unless you have dropped a V8 into your Datsun 1200 in which case they are no longer overbuilt and wouldn't pass my eyeball test either).

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julesmoto said..

MAGNESIUM said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

Jules does your yacht have keel bolts?
i know it's iron which I was always against until I found out a lead keel bolted on has to be recast to to do the bolts unlike cast you can just screw straight back in .

Yep 12 keel bolts in a double row (except for the first and last) with the tops of the staggered bolts and nuts clearly visible under the floorboards in my nice clean dry as a bone bilge which I look at every time I get on the boat.

If they were ever to start leaking salt water I would be hauling out and the keel would be coming off pronto.

I did have a bit of a panic when there was water in there shortly after I bought the boat which thankfully turned out to be a water tank leaking.

As for overhead dome nuts they are certainly better than long jagged bolt ends but they could still smash your skull and I have some which extend through the ceiling panels beneath my life raft on the coach house roof which I'm not too thrilled about.

I'm not too worried about fatigue on my boat and I know that aircraft air frames need replacing and checking all the time because they are quite highly stressed. The reason why I'm not overly worried about fatigue for my keel bolts even though they are probably 39 years old is that there is no hint of hairline cracks in the fairing between the keel and Hull when the boat is pulled out on a travel lift with the keel hanging. I don't think the fairing is flexible to any extent so if there was any movement in the keel bolts I would expect to see a hairline crack. Mine also look sufficiently chunky according to my 68 year trained eyeball/gut feel test. Aircraft frames on the contrary have to be built light as possible (like serious sports/racing yachts) so move around quite a lot and hence are not as overbuilt and fatigue. I'm not a engineer but that is my understanding.
Similar reason why your steel sub floor and firewall car stringers/rails are not going to fatigue and snap (unless you have dropped a V8 into your Datsun 1200 in which case they are no longer overbuilt and wouldn't pass my eyeball test either).

Like you I was skull dragged across the channel , it was incredibly savage on the keel , I was very apprehensive out at sea checking for leaks .
has given me a lot more faith in the keel bolts.
the nuts look to be in very good condition no sign of rust BUT what is going on deep inside with no oxygen getting to the stainless it really worries me.

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MAGNESIUM said..

julesmoto said..

MAGNESIUM said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

Jules does your yacht have keel bolts?
i know it's iron which I was always against until I found out a lead keel bolted on has to be recast to to do the bolts unlike cast you can just screw straight back in .

Yep 12 keel bolts in a double row (except for the first and last) with the tops of the staggered bolts and nuts clearly visible under the floorboards in my nice clean dry as a bone bilge which I look at every time I get on the boat.

If they were ever to start leaking salt water I would be hauling out and the keel would be coming off pronto.

I did have a bit of a panic when there was water in there shortly after I bought the boat which thankfully turned out to be a water tank leaking.

As for overhead dome nuts they are certainly better than long jagged bolt ends but they could still smash your skull and I have some which extend through the ceiling panels beneath my life raft on the coach house roof which I'm not too thrilled about.

I'm not too worried about fatigue on my boat and I know that aircraft air frames need replacing and checking all the time because they are quite highly stressed. The reason why I'm not overly worried about fatigue for my keel bolts even though they are probably 39 years old is that there is no hint of hairline cracks in the fairing between the keel and Hull when the boat is pulled out on a travel lift with the keel hanging. I don't think the fairing is flexible to any extent so if there was any movement in the keel bolts I would expect to see a hairline crack. Mine also look sufficiently chunky according to my 68 year trained eyeball/gut feel test. Aircraft frames on the contrary have to be built light as possible (like serious sports/racing yachts) so move around quite a lot and hence are not as overbuilt and fatigue. I'm not a engineer but that is my understanding.
Similar reason why your steel sub floor and firewall car stringers/rails are not going to fatigue and snap (unless you have dropped a V8 into your Datsun 1200 in which case they are no longer overbuilt and wouldn't pass my eyeball test either).

Like you I was skull dragged across the channel , it was incredibly savage on the keel , I was very apprehensive out at sea checking for leaks .
has given me a lot more faith in the keel bolts.
the nuts look to be in very good condition no sign of rust BUT what is going on deep inside with no oxygen getting to the stainless it really worries me.

I guess you can only hope it won't be all 12 at once and that there will be warning signs.

When I bought the NS38 I was really keen on a boat with no keel bolts but finding one of those which satisfies a number of other criteria like good condition, right size... is like looking for a unicorn.

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julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

The helmet comment was referring to how violent
an inversion would be if the centre of gravity was suddenly moved, ie a fin keel falling off. I imagine it would make a wind driven knock down seem graceful

ISO 12215.9 is the usual standard now for keel bolts.

cdn.standards.iteh.ai/samples/55339/7a7b322a16be4c18a230800fc71c8a02/ISO-12215-9-2012.pdf

www.iso.org/standard/55339.html

d7qh6ksdplczd.cloudfront.net/sailing/wp-content/uploads/2022/10/22085443/SPSC_5ai-WS-Letter.pdf

Our Ross 930 circa 1985 build but with the 2.22m deep steel fin and lead bulb keel rather than the original IOR style 1.8m deep trapezoidal cast iron keel has the 2 single centreline keel bolts close to the leading and trailing edges and 4 wide spaced pairs between - obviously the welded keel skins and internal stiffeners to the keel top baseplate - with all csunk fasteners outside the aerofoil shape into the baseplate and up into the keel floors. Keel bolts and nuts to A4-80 stainless. Will post photos.

My Oceanis is 10 years older than Cheeki Rafiki was but you can definitely eyeball and put your fingers on all our keel bolts. Replaced them all only 12 months ago. Need to move the hot water service to put a socket on three of them but can still see and touch 'em anytime.

I've chartered three or four similar boats (Beneteau, Jeanneau) and from memory could be seen in all cases.

To my mind these are a service item and must be renewed periodically, just like many other bits on our boats. I remember reading the report on Cheeki Rafiki before I bought my boat and it does seem that her maintenance could have been better.

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woko said..

The helmet comment was referring to how violent
an inversion would be if the centre of gravity was suddenly moved, ie a fin keel falling off. I imagine it would make a wind driven knock down seem graceful

Yes thanks I got the significance of the helmet.

As a motorcycle rider most of my life I was interested to read 15 or 20 years ago that the wearing of a helmet in a car would prevent a lot of injuries and for example probably make
side curtain airbags redundant. Styrofoam style push bike helmets with purely decorative coverings would involve very little inconvenience so the idea is possibly not as funny as it sounds.
Some around the world solo sailors have elaborate seats with full harnesses seatbelts directed towards surviving rollovers. I think someone in the recent Golden Globe had such an arrangement.
Not sure a loss of keel knock down would be that much more severe than one caused by a large rogue wave and gust as once at 90 degrees presumably the sails would damp motion through the next 90 degrees. A gaping hole where the keel used to be would probably be a bit of a problem if the keel takes chunks of hull with it. That however would be more of a hull or floor failure rather than a bolt failure.

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Serenite said..
My Oceanis is 10 years older than Cheeki Rafiki was but you can definitely eyeball and put your fingers on all our keel bolts. Replaced them all only 12 months ago. Need to move the hot water service to put a socket on three of them but can still see and touch 'em anytime.

I've chartered three or four similar boats (Beneteau, Jeanneau) and from memory could be seen in all cases.

To my mind these are a service item and must be renewed periodically, just like many other bits on our boats. I remember reading the report on Cheeki Rafiki before I bought my boat and it does seem that her maintenance could have been better.

You are lucky that they are bolts not nuts like most although I suppose putting a second nut on and turning the lower one would have the same effect. The internal floor liner as well as glassed floors (they are higher than the nuts and bolts) in my boat prevents that however so all I can do is get a socket directly above the single nuts so that I have enough room to swing my torque wrench/ breaker bar. This of course is only any good for tensioning up not removing. Removing would be a keel off affair with lots of rebedding and fairing plus fingers crossed that the keel actually dropped without pulling chunks of hull with it due to original bedding in some super adhesive like 5200.

Lots of videos on the web where keels won't drop despite the bolts or nuts being removed.

Maybe it's easier to wear a helmet ;).

Keep in mind that stainless fasteners are susceptible to thread galling.

www.assda.asn.au/images/PDFs/faq%20no5%20galling.pdf

Suggest don't re-tighten stainless keel bolts unnecessarily.

Our Ross 930 high tensile stainless keel bolts (A4-70 grade) are approaching 40yrs old and are not in need of replacement as far as I am aware based on careful visual inspection each yearly slipping. Of course NDT examinations would be needed to confirm this. They have double nuts and are CorrosionX sprayed yearly to try and prevent galling in case we need to renew them.

Would not classify keel bolts as a "service item", apologies. What time frame is "periodically"?

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r13 said..
Keep in mind that stainless fasteners are susceptible to thread galling.

www.assda.asn.au/images/PDFs/faq%20no5%20galling.pdf

Suggest don't re-tighten stainless keel bolts unnecessarily.

Our Ross 930 high tensile stainless keel bolts (A4-70 grade) are approaching 40yrs old and are not in need of replacement as far as I am aware based on careful visual inspection each yearly slipping. Of course NDT examinations would be needed to confirm this. They have double nuts and are CorrosionX sprayed yearly to try and prevent galling in case we need to renew them.

Would not classify keel bolts as a "service item", apologies. What time frame is "periodically"?

Great to hear those thoughts on stainless bolts, do you think the bolt hidden deep inside the keel can hide corrosion from lack of oxygen ? Being stainless?

There has be a simple understanding reached that if you take a stainless steel bolt into outer space it will not corrode due to lack of oxygen.
It's a two part equation that corrodes stainless Metals ,,, lack of oxygen "IN" a corrosive environment.

Thanks Jolene. Many good web links eg

www.morganscloud.com/2020/06/05/planning-and-budgeting-a-refit-keels-part-2-non-destructive-testing-of-bolts/#:~:text=The%20reason%20being%20that%20if,longer%20stainless%20and%20so%20rusts.

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cisco said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

If I can't see the keel bolts when I lift the cabin sole I would not own the boat. If the keel bolts are in line single row I would not own the boat, Keel bolts must be double row or if single row alternatively angled as in S&S 34.

Also for through deck bolts dome nuts are the answer.

Not quite with the S&S. The keel bolts have one up forard then in pairs affest until the stern one on its own. The bolts mid keel are about 15-20cm apart.
Onn Morning Bird they are all visible and accessible just by lifting a board.

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MorningBird said..

cisco said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

If I can't see the keel bolts when I lift the cabin sole I would not own the boat. If the keel bolts are in line single row I would not own the boat, Keel bolts must be double row or if single row alternatively angled as in S&S 34.

Also for through deck bolts dome nuts are the answer.

Not quite with the S&S. The keel bolts have one up forard then in pairs affest until the stern one on its own. The bolts mid keel are about 15-20cm apart.
Onn Morning Bird they are all visible and accessible just by lifting a board.

Most Swarbrick ss 34's have 9 studs,,, 3 pairs and 3 singles and for the boats with a mid mounted engine, the engine really needs to be shifted out of the way to access 5 of them.

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Jolene said..


Most Swarbrick ss 34's have 9 studs,,, 3 pairs and 3 singles and for the boats with a mid mounted engine, the engine really needs to be shifted out of the way to access 5 of them.

Yes mine would require lifting the engine up temporarily.

There have been couple of ss34's that have had the mid mounted engine removed and replaced with an aft engine and sail drive combination. Because the stern tube is then removed the owners have then taken the opportunity to fit an extra stud aft. I'm not sure if all ss34 that where fitted with sail drives from the beginning have the extra stud or a larger span between the studs but they really should have given the large amount of unsupported keel aft of the 9th stud that the mid engine boats have.

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Jolene said..

MorningBird said..

cisco said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

If I can't see the keel bolts when I lift the cabin sole I would not own the boat. If the keel bolts are in line single row I would not own the boat, Keel bolts must be double row or if single row alternatively angled as in S&S 34.

Also for through deck bolts dome nuts are the answer.

Not quite with the S&S. The keel bolts have one up forard then in pairs affest until the stern one on its own. The bolts mid keel are about 15-20cm apart.
Onn Morning Bird they are all visible and accessible just by lifting a board.

Most Swarbrick ss 34's have 9 studs,,, 3 pairs and 3 singles and for the boats with a mid mounted engine, the engine really needs to be shifted out of the way to access 5 of them.

Morning Birds could be accessed under the engine. We had them all checked and tightened during the survey when I sold her .

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MorningBird said..

cisco said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

If I can't see the keel bolts when I lift the cabin sole I would not own the boat. If the keel bolts are in line single row I would not own the boat, Keel bolts must be double row or if single row alternatively angled as in S&S 34.

Also for through deck bolts dome nuts are the answer.

Not quite with the S&S. The keel bolts have one up forard then in pairs affest until the stern one on its own. The bolts mid keel are about 15-20cm apart.
Onn Morning Bird they are all visible and accessible just by lifting a board.

Cicely June, the first S&S 34 to come to Australia had a single row of alternatively out ward angled keel bolts which allowed easy access to the bottom nuts. From memory the bottom nut cavity was just filled with some sort of bog.

The outward angling eliminated localised stress at the keel to hull point.

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cisco said..

MorningBird said..

cisco said..

julesmoto said..

woko said..
You might want to put a helmet on and stay above decks too.The bene we chartered a couple of years ago had double skin around the garboard area that made it difficult to determine were a bit of water sloshing around the bilge was coming from, let alone even see the keel fixings.

Yeah because nobody wants to check, service or heaven forbid see ugly things like bolts.

Hell I'm not even convinced that I like headlinings. Mind you I particularly dislike through deck bolts that aren't cut off just after the nut although a small rebated teak cover is still safer. Helmet again?

If I can't see the keel bolts when I lift the cabin sole I would not own the boat. If the keel bolts are in line single row I would not own the boat, Keel bolts must be double row or if single row alternatively angled as in S&S 34.

Also for through deck bolts dome nuts are the answer.

Not quite with the S&S. The keel bolts have one up forard then in pairs affest until the stern one on its own. The bolts mid keel are about 15-20cm apart.
Onn Morning Bird they are all visible and accessible just by lifting a board.

Cicely June, the first S&S 34 to come to Australia had a single row of alternatively out ward angled keel bolts which allowed easy access to the bottom nuts. From memory the bottom nut cavity was just filled with some sort of bog.

The outward angling eliminated localised stress at the keel to hull point.

I recall Cicely June was a Winfield (UK) built 34. All the Swarbrick built ones I've seen had them the same as MBs.
They did have to be tightened occasionally on MB. The first time when I had just bought her and had the engine out at home for a rebuild. The slipway guys wondered why I wanted it done. For peace of mind I said.
And then when she was sold, the surveyor found slight movement in the keel. The chippie at Woolwich tightened the keel nuts with a socket on an extension arm that must have been 1.5 metres long. He could get to all the nuts under the engine without any difficulty. No more keel movement.
In between these two nut tightening's MB had covered about 10,000 miles at sea including the three Lord Howe trips.