Keel Failure in the Canaries

[arsenelupiga]

Originally Posted by billknny

Errr... This is about the goofiest thing anybody has written here in a long time (and that's a very high bar). I'll just assume you are trying (and failing) to be funny

Not funny at all.

I know and you know that you worry about what I said, because it is true.

99% chance you will be allright. Especially if you motor.

[De.windhoos]

Originally Posted by GTom

(remember, cheeky rafiki was surveyed before embarking that last jurney...). It is often the question: how much abuse a boat can take and how obvious is the damage after a grounding, etc. Also, what are the consequences of a failure in the middle of the ocean? If an encapsulated keel for some reason wreaks havoc and causes a bad leak, you'll have time for a mayday call and abandon to your liferaft in an orderly manner. The poor crew of Cheeky Rafiki didn't have that luxury.

Umm not true on several levels.

1. The boat was badly maintained
2. It only had a category 2 commercial license and that was not renewed.
3. The skipper contacted the owner about leaks but the owner didn’t take it seriously

Read the verdict on the case

[Polux]

Originally Posted by arsenelupiga

Not funny at all.
I know and you know that you worry about what I said, because it is true.
....

Originally Posted by arsenelupiga

monohulls.. this is structural issue waiting to explode and i would not dare sailing one except in bays. Vibrations from going upwind, which is favourite point of sail for monhullers, tire material and expose crew to mortal danger where there is < 30% chances of survival.
...

Well, I thought you were kidding too. It is sad that you were not

[Polux]

Originally Posted by De.windhoos

Umm not true on several levels.

1. The boat was badly maintained
2. It only had a category 2 commercial license and that was not renewed.
3. The skipper contacted the owner about leaks but the owner didn’t take it seriously

Read the verdict on the case

This boat has something more in common with Cheeky Rafiki, it was a boat used for charter too and the hull was also recovered. It will be surveyed, so, hopefully, we will know what was the cause of the accident.

[longjonsilver]

One of the reasons that i am looking at trimarans is because they have no keel to fall off. No one knows how many boats have been lost at sea because their keels fell off. Crevice corrosion of the SS keel bolts is occurring every day and as our boats get older, we will see more failures. With Mars Keel wanting north of $300 per keel bolt plus shipping for replacement of keel bolts, i have decided that it is too much hassle to worry about keel bolts and a trimaran is in my future.

[robert sailor]

Originally Posted by Polux

Well, I thought you were kidding too. It is sad that you were not

Polux my friend, no reason to be sad. Just because a person can operate a keyboard does not mean that any of their opinions are valid. Either the poster is pulling your wire or he simply is uninformed, either way it should mean nothing to you as its possible that you forgot more about sailing in the last hour than he has ever learned in his life.b

[De.windhoos]

Originally Posted by longjonsilver

One of the reasons that i am looking at trimarans is because they have no keel to fall off. No one knows how many boats have been lost at sea because their keels fell off. Crevice corrosion of the SS keel bolts is occurring every day and as our boats get older, we will see more failures. With Mars Keel wanting north of $300 per keel bolt plus shipping for replacement of keel bolts, i have decided that it is too much hassle to worry about keel bolts and a trimaran is in my future.

To minimize other risks I would advise to also remove the mast, they tend to break.

[jtsailjt]

Originally Posted by arsenelupiga

Not funny at all.

I know and you know that you worry about what I said, because it is true.

99% chance you will be allright. Especially if you motor.

Our boat has encapsulated ballast but I wouldn't avoid buying a boat with a bolt on keel because I was afraid of it falling off. My previous 2 boats had bolt on keels and I had no worries about their keels falling off. It's one of those things that very rarely happens but always makes headlines when it does, sort of like getting struck by lightning. If the bolts are kept tight so there's no movement and the boat has no history of hard grounding, then they last for a long time. But there's always that small chance of hidden corrosion on still shiny, stainless or monel keel bolts so if it's something you find yourself worrying about, then it's not that huge a deal to drop the keel during the next haulout and have the bolts replaced so you have brand new ones and can stop worrying. But realistically, probably only about one percent of monohull owners have anything to worry about, hardly a reason to avoid boats with bolt on keels.

[jtsailjt]

Originally Posted by longjonsilver

One of the reasons that i am looking at trimarans is because they have no keel to fall off. No one knows how many boats have been lost at sea because their keels fell off. Crevice corrosion of the SS keel bolts is occurring every day and as our boats get older, we will see more failures. With Mars Keel wanting north of $300 per keel bolt plus shipping for replacement of keel bolts, i have decided that it is too much hassle to worry about keel bolts and a trimaran is in my future.

Really, you'd get a trimaran just to avoid spending a few thousand dollars to buy your boat brand new keel bolts? I guess we all have our own ideas about what constitutes "too much hassle" and that's fair, but I think there are a LOT of other bigger issues to worry about than your keel bolts failing catastrophically.

[robert sailor]

Originally Posted by jtsailjt

Our boat has encapsulated ballast but I wouldn't avoid buying a boat with a bolt on keel because I was afraid of it falling off. My previous 2 boats had bolt on keels and I had no worries about their keels falling off. It's one of those things that very rarely happens but always makes headlines when it does, sort of like getting struck by lightning. If the bolts are kept tight so there's no movement and the boat has no history of hard grounding, then they last for a long time. But there's always that small chance of hidden corrosion on still shiny, stainless or monel keel bolts so if it's something you find yourself worrying about, then it's not that huge a deal to drop the keel during the next haulout and have the bolts replaced so you have brand new ones and can stop worrying. But realistically, probably only about one percent of monohull owners have anything to worry about, hardly a reason to avoid boats with bolt on keels.

Not wanting to ruin your otherwise good post but if bolt on keels had a 1% chance of falling off you'd never get anyone sailing them. I don't know what the real number is but I can tell you it won't be anywhere near 1%.

[Suijin]

Originally Posted by arsenelupiga

Not funny at all.

I know and you know that you worry about what I said, because it is true.

99% chance you will be allright. Especially if you motor.

I dunno, I thought it was pretty goofy too. But I guess I should know it's true (and worry about it), since you both know that it's true, and you know that he worries about it...or something like that.

Where did you get your statistics of a 1% chance of bolt-on keels falling off? You seem pretty convinced of their inferiority and certainty of failing. Must be based on facts, I assume.

[SV DestinyAscen]

Originally Posted by Polux

Can you elaborate on that? A keel that fall off at a marina? or was just some bolts that broke? On the marina?

It was facetious. Perhaps a language barrier, but like I said - ppl spend too much time making up facts justifying their preferred mode of failure.

The way some ppl talk about inherent dangers of boats, you'd wonder if they want to be at sea in anything less robust than a nuclear ice breaker.

[CarlF]

I"ve never understood why bolt on keels aren't engineered differently to reduce the risk from keel bolt failure. Obviously it's cheaper, but boat builders often differentiate their product with superior build practices that cost more (e.g. watertight bulkheads). It seems folly to just bolt to a flat hull surface.

a) A 12" deep female socket molded into the bottom of the boat that receives the keel. Secured by horizontal bolts and vertical bolts.

or

b) A male and female bolt post with the bolt in the middle so that the bolt in only holding the keel up not handling longitudinal force such as a grounding.

or

c) keels cast with a threaded insert to receive a bolt that is screwed in from inside the boat - that can be removed and checked on a regular schedule without dropping the keel.

Has anyone seen boats with this or something similar?

[jtsailjt]

Originally Posted by robert sailor

Not wanting to ruin your otherwise good post but if bolt on keels had a 1% chance of falling off you'd never get anyone sailing them. I don't know what the real number is but I can tell you it won't be anywhere near 1%.

Ok, how about 1% +/- .99%? Close enough? Who knows what the precise number is, but to clarify, I meant the number of boats with bolt on keels whose owners might possibly have something to worry about enough to have the bolts inspected or replaced as a preventative measure, not that 1% of the keels were about to drop off on any given day.

For example, my last boat was a Nordic 44 with a long fin keel that was over a foot wide and was securely bolted on with several oversized looking keel bolts that could easily be seen at the bottom of the bilge and kept tightened. These boats are very ruggedly built and have no history of keels falling off. But the boat is now 32 years old so if I were still the owner, before crossing an ocean, I'd have the keel dropped and the bolts inspected and replaced as necessary just for my peace of mind. I'm not usually much of a worrier but am not willing to bet my life on some stainless steel that hasn't had a whiff of oxygen in 32 years! Of course if it had ever been hard grounded that's also a reason why I'd want it hauled and the ballast attachment inspected.

[SV DestinyAscen]

Originally Posted by CarlF

I"ve never understood why bolt on keels aren't engineered differently to reduce the risk from keel bolt failure. Obviously it's cheaper, but boat builders often differentiate their product with superior build practices that cost more (e.g. watertight bulkheads). It seems folly to just bolt to a flat hull surface.

a) A 12" deep female socket molded into the bottom of the boat that receives the keel. Secured by horizontal bolts and vertical bolts.

or

b) A male and female bolt post with the bolt in the middle so that the bolt in only holding the keel up not handling longitudinal force such as a grounding.

or

c) keels cast with a threaded insert to receive a bolt that is screwed in from inside the boat - that can be removed and checked on a regular schedule without dropping the keel.

Has anyone seen boats with this or something similar?

There are a lot of French fast cruisers with lifting keels where the keel box is molded into the hull and a horizontal pin holds the keel in place with a hydraulic ram applying tension to the blade keel. Simple and uses leverage against movement.

Some yards have external wedge on the hull that the keel fits over.

Think the common theme is... avoid fatiguing bolts with insufficient tension that allows movement. Staggered bolt patterns have higher margin of safety than single file. Maintain your boat.