Encapsulated = invulnerable ??

[Greg K]

Originally Posted by boatman61

I don't know, I found it quite interesting.. it was not a condemnation of fin keels, more an explanation of how they work, the pressures and design parameters.. .

Yup, good article. Practical Sailor and Ocean Navigator are probably the only magazines left that are readable any more. Worth reposting the link https://www.practical-sailor.com/sai...-vs-full-keels

[coopec43]

Originally Posted by boatman61

I don't know, I found it quite interesting.. it was not a condemnation of fin keels, more an explanation of how they work, the pressures and design parameters.. and what can happen when skimpy design and poor maintaince combine eg Cheeky Rafiki.
Not forgetting the Brit solo RTW competitor Tony Bullimore who had to survive for around 4 days in his upturned hull when his keel fell off in the Southern Ocean.. luckily he was found.

Edited after looking up his name.
These were two separate types of failure, CR was the keel ripping out the hull, TB was a clean sheer, luckily the keel stubs stayed in place allowing air to be trapped inside preventing him sinking.

There's been two more (if you forget the Volvo type yachts).

(Ran Tan)14 May 2020 — It was a calm, mid-Pacific morning, around 1000 on May 31, 2019, when ... yacht had suffered a major keel failure and that it would soon fall off.

2018(?) Couple's SAILBOAT Sinks TWO DAYS After Departing When Keel Falls Off | Exclusive Interview. Nikki Walsh and Tanner Broadwell bought at $5,000 1969 Columbia 28-foot sailboat to sail around the world. Their trip lasted 2 days

Yachts now have to be built to certain standards but that doesn't sort out the problems yachts that are currently sailing
.
https://www.vgyd.com//wp-content/upl...Off-9-5-13.pdf


Keel and rudder inspection notices available from Australian Sailing

Past WMYC Commodore Jim Fern shared an anecdote about the Farr half tonner Springloaded he previously owned. When once checking her keel six of the nine stainless steel keel bolts broke or disintegrated when tightened using a torque wrench. Fern discovered that the nuts had ‘work-hardened’ and became brittle. Fortunately, the discovery was made during routine maintenance and not offshore.

https://www.mysailing.com.au/keel-an...alian-sailing/

[coopec43]

Originally Posted by Greg K

Yup, good article. Practical Sailor and Ocean Navigator are probably the only magazines left that are readable any more. Worth reposting the link https://www.practical-sailor.com/sai...-vs-full-keels

Absolutely!

I often read and appreciate a Practical Sailor article and think I should subscribe to the magazine but balk at it when I see the cost. But Why? Before the internet I had no trouble forking out $?? per year for paper versions of Sail Magazine or Cruising Sailor.

[dfelsent]

I keep thinking there are far more choices than encapsulated or bolt on.
Look at the construction of a full keel wooden boat. Maybe just internal ballast. Or a shoe. Or my glass boat that has bronze floors welded to the bronze centerboard trunk with ballast on the outside of the trunk. All glassed together but the keel sure isn’t encapsulated. And the trunk is entirely sealed and below the waterline and sole.
Look at an Ovni. Or the Garcias.
There are lots of other design solutions too.

[boatman61]

Sure are..

[coopec43]

Originally Posted by dfelsent

I keep thinking there are far more choices than encapsulated or bolt on.
Look at the construction of a full keel wooden boat. Maybe just internal ballast. Or a shoe. Or my glass boat that has bronze floors welded to the bronze centerboard trunk with ballast on the outside of the trunk. All glassed together but the keel sure isn’t encapsulated. And the trunk is entirely sealed and below the waterline and sole.
Look at an Ovni. Or the Garcias.
There are lots of other design solutions too.

The keel loads are spread out over a large area of the hull so that is OK according to the experts

[coopec43]

Originally Posted by wingssail

........... damage to the hull clearly seen in the accompanying photograph.

In the last two years I have seen 5 vessels wrecked within a few miles of here (not including Danika, which was previous to that). Three of them were full keel, encapsulated keel, cruising sailboats. Two were bolted on fin keel boats. Three of the five dragged onto rocks while anchored, two were sailed onto the shore due to poor navigation. All the full keel boats were destroyed when the fiberglass hulls were shattered, both in keel area and in the basic hull structure. Of the two fin keel boats, one's keel broke off but the other, while it had holes in the hull large enough for a person to climb through, retained it's bolt on lead keel and that vessel, the only one of the five, was salvaged and is again sailing.

Other fin keel vessels have sailed directly onto reefs or islands without loosing their keels, such as the Deerfoot Moonshadow.

It is not clear to me that there is any advantage to having an encapsulated, full keel, boat if you are going to let it drag onto a reef or sail into an island.
.

https://assets.publishing.service.go..._Grounding.pdf

© Crown Copyright 2018

[Nyanza Cav32]

I wonder what you're after here, perhaps some kind of a universal concession that bolt on keels aren't safe? The examples you gave here prove nothing, except that you seem a little desperate to prove a point which doesn't actually exist. They do earn a comment or two, however.

The first example, an old 28' Columbia, which apparently sank after the keel just fell off. It obviously had a major problem which the owners did not detect, most likely related to a lack of maintenance or severe damage; at $5000, it doesn't sound like the boat was likely to be in great condition. Did the new owners have the boat thoroughly inspected by a professional for its seaworthiness before they departed? Bolt on keels do not just drop off for no reason.

The second example wasn't actually a problem at all. It is common for stainless nuts which have been in place for many years in a salt water environment to fail when an attempt to retorque them is made. So they were replaced...no problem. The reason they broke was because they had become brittle and were subjected to high torque, but that does not mean they were ready to let go at any moment had they not been touched. Yes, they should be checked periodically during haul out, and replaced as a matter of routine after about 15 years, just as any other critical mechanical connection (eg standing rigging) on a boat should.

Neither of these anecdotes makes any case for your expressed view that bolt on keels are inherently vulnerable to sudden failure. You have a preference, that's fine, there are pros and cons for every design option.

The experience related to us here of a boat with a glassed in keel which very nearly sank due to a clear, major inherent flaw serves as an aid to those who have a boat with the same or similar system; they may not be as invulnerable as they may have thought. If I had one, I would act to seal off the keel...no more problem. It doesn't make them bad boats, it isn't an attack on encapsulated keel boats, there is no need to go into a defensive, 'but what about...' mode. It's not an us versus them exercise. I also recognise that the relating to us of the anecdotes you found is not without value; like the story which headlines this post, they will hopefully remind owners of the need to think about and check their boat for problems.

[wingssail]

Originally Posted by coopec43

https://assets.publishing.service.go..._Grounding.pdf

© Crown Copyright 2018

Coopec43, you are cherry picking. A similar caution could be written about encapsulated keels. Also about masts, rudders, engine mounts, autopilots, and almost every thing in a yacht. Nothing in the draft document says anything will happen, just that it is possible. But, in fact, much of the document could be disputed by many naval architects.

It is also funny we don't see encapsulated wings on aircraft, they are all "bolt on"

The bottom line is that the vast majority of vessels now days are built with bolt on fin keels, are designed by architects who are well aware of the strength requirements, and are safely navigating the world's oceans and many have been for decades without incident.

If you were sincere you might consider the number of full keel vessels which have been grounded and lost once the hull structure has been breached. Any vessel, full keel or bolt on fin, will likely be lost once the hull structure has been punctured by rocks or reefs, and that occurrence is far more likely than the the loss of a keel on a fin keel boat, numerically speaking.

So your cherry picking of facts and reports simply reveals your prejudice and does a gross disservice to to uninformed newbies who might benefit from an unbiased report which covers all risks on a vessel, not just the one on which you choose to focus.

[coopec43]

Originally Posted by Nyanza Cav32

.

The experience related to us here of a boat with a glassed in keel which very nearly sank due to a clear, major inherent flaw serves as an aid to those who have a boat with the same or similar system; they may not be as invulnerable as they may have thought. If I had one, I would act to seal off the keel...no more problem. It doesn't make them bad boats, it isn't an attack on encapsulated keel boats, there is no need to go into a defensive, 'but what about...' mode. It's not an us versus them exercise. I also recognise that the relating to us of the anecdotes you found is not without value; like the story which headlines this post, they will hopefully remind owners of the need to think about and check their boat for problems.

You say "It's not an us versus them exercise". Did you read Jim's opening comment?

Have a look at the very first post on this thread!


"For a chilling look at what can go wrong with an encapsulated keel, have a look at this story in electronic Latitude:

https://www.latitude38.com/lectronic...gy-pizza-lunch

I'm not sure what marque the boat is, but the message is clear: this particular near sinking would not have happened with a bolt on keel!

Jim"

Jim says "it would not have happened with a bolt on keel" : I am saying a fin keel would not necessarily have been less vulnerable.

"There are facts, and there are beliefs, and there are things you want so badly to believe that they become as facts to you".

[Jim Cate]

Jim says "it would not have happened with a bolt on keel" : I am saying a fin keel would not necessarily have been less vulnerable.

Hold on a minute there coopec! Jim (that's me) didn't say that at all. He said (quoting what I actually did say) that "this particular near sinking would not have happened with a bolt on keel!

Note the phrase "This particular near sinking". Please explain how a bolted on solid chunk of metal could have a hole abraded into it that would cause flooding of the hull? Ripped off by a severe impact? Possibly, but not so very likely, but that is a different kind of trauma. I reiterate that a fin keel could not have suffered the same fate in this incident.

But really, the point I was trying to illustrate is that the commonly expressed (here on CF) faith that there are no failure modes in encapsulated keels should not be taken as gospel. There are several possible failures, none common... just as failures of fin keels that are not on race boats are not common.

So, in closing I'll just say that your kinda snarky final comment:

"There are facts, and there are beliefs, and there are things you want so badly to believe that they become as facts to you".

could apply to yourself as well!

Jim

[Nyanza Cav32]

Jim was correct, that particular issue, chafing damage to the keel directly opening the boat up with a catastrophic leak, does not exist with a bolt on keel. However, I don't believe he was implying that they are not vulnerable to damage in other ways, of course they are, just not in that particular way, and not to the extreme extent (keel, rudder, prop all being ripped out, sinking the boat) you tried to tell us would invariably be the case.

[coopec43]

Jim

The chain would have probably ripped off the skeg and rudder of a fin keeled yacht causing it to sink.


Right now as I am about to put my yacht in the water I freak out when I read:

About two out of every three (69 percent) boats sink at the dock or mooring, while the remainder (31 percent) sink while underway. Of all of the dock/mooring sinkings, 39 percent occur when some small part gives up the fight with water due to wear, tear and corrosion

I'll certainly put a lid on the back most compartment of the keel. I have high capacity bilge pumps and an audible alarm

[Jim Cate]

Originally Posted by coopec43

Jim


The chain would have probably ripped off the skeg and rudder of a fin keeled yacht causing it to sink.

You have a vivid imagination and a strong desire to be right.

And BTW, at least on my boat having the rudder and skeg ripped off would take a rather unlikely set of circumstances and a huge effort... and it still wouldn't sink because she has a watertight crash bulkhead between the rudder/skeg area and the accommodation area.

Jim

[Uncle Bob]

Originally Posted by Jim Cate

You have a vivid imagination and a strong desire to be right.

And BTW, at least on my boat having the rudder and skeg ripped off would take a rather unlikely set of circumstances and a huge effort... and it still wouldn't sink because she has a watertight crash bulkhead between the rudder/skeg area and the accommodation area.

Jim

Jim, confirmation bias is really strong in some.