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Old 22-01-2022, 09:06   #1
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Amel SM - Bolted on keel?

Hey all,

I’m seriously considering an Amel Super Maramu (budget under £200k) as my boat of choice for a multi year voyage around the world, with particular emphasis on South Pacific islands, Caribbean and the cooler climates of the Scandinavian countries.

I’m attracted to the Amel because of well thought through features including ketch rig, engine access, hard dodger, storage, water tight bulkheads, fridge / freezers space, large water tanks (with clever gauges), large diesel tanks etc and the fact little adaptation will be required.

The only thing I’m slightly dubious about is the keel. I was well under the assumption for a few years now that older Amels are bullet proof (this may still be the case), however after some in depth reading I understand that the keel is bolted on.

There is lots of negative information around bolted on keels and blue water cruising and some horror stories (keels falling off) to go with it. However the added security that encapsulated keels provide is one less thing to worry about (especially with potential groundings in low waters of the Caribbean or uncharted waters of the South Pacific.

With Amels major focus being on safety, their choice of a bolted on keel for the Maramu, Super Maramu, Santorin and Sharki must have been justified.

So the information I’d like to understand is did Amel use differing techniques for the construction of their bolted keels for extra bullet point strength? Does this differ in comparison to techniques used in modern day bolted on keels that bad stories (cheeki rafiki) have arisen? Have I misunderstood, are Amel keels encapsulated?

Thanks,
J
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Old 22-01-2022, 09:14   #2
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Re: Amel SM - Bolted on keel?

On a boat with a good track record like that, I wouldn't worry about a bolt on keel. Just make sure the bolts and everything else around the joint are in good condition.

In general, there's no reason a bolt on keel is any weaker. If the hull isn't strong enough around the keel attachment and the keel loads aren't spread through enough hull surface, any keel can be snapped off, bolt on or otherwise.

But if the keel area is strong enough, the mounting surface is big enough and spreads load well (typically through use of a short keel stub that the keel bolts to rather than just bolting right to the bottom of the hull), bolts are sized well enough, etc. you'd probably tear the whole hull apart before the keel attachment failed.


Basically, failures like you're thinking of aren't due to a specific keel attachment method or anything, but due to a poorly engineered boat (or one that is damaged and improperly repaired leaving a weak area).
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Old 22-01-2022, 09:21   #3
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Re: Amel SM - Bolted on keel?

I've been on a smaller version of the SM and was very impressed by the build quality and the thoughtful features. Bolt on keels could be a drawback depending on the engineering and track record of the builder. While there is probably a bigger risk of failure than with an encapsulated keel, I've never heard of a keel falling of an Amel so I wouldn't be too worried about it.
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Old 22-01-2022, 09:24   #4
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Re: Amel SM - Bolted on keel?

Thinking about it, there have been plenty of encapsulated keels with design flaws over the years. Such as a bilge compartment extending very far down into the keel at a leading or trailing edge. That opens up the opportunity for a hull breach in a grounding that's much deeper than would be possible on a fin keel, meaning much greater possible water ingress.
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Old 22-01-2022, 09:50   #5
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Re: Amel SM - Bolted on keel?

Greetings and welcome aboard the CF, Jezroc.
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Old 22-01-2022, 12:45   #6
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Re: Amel SM - Bolted on keel?

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Originally Posted by rslifkin View Post
Thinking about it, there have been plenty of encapsulated keels with design flaws over the years. Such as a bilge compartment extending very far down into the keel at a leading or trailing edge. That opens up the opportunity for a hull breach in a grounding that's much deeper than would be possible on a fin keel, meaning much greater possible water ingress.
I have been intrigued by the ongoing discussions about the desirability of moulded-in keels versus bolt-on. As rslifkin has pointed out, even moulded-in keels can have issues. I am thinking particularly about one slip neighbour with a Northern 25. Their boat had a moulded-in, full-depth keel with lead ballast bolted to the leading edge, very close in nature to the encapsulated ballast keel which everyone considers to be the gold standard for safety and reliability. However, their keel had a deep bilge at the stern portion, behind the ballast. When the trailing edge of the keel got caught on the anchor chain for a stern mooring can, the chain sawed its way through the back edge of the keel and their boat immediately began to sink. The same thing could have happened had they bounced against a rock or a coral head.

For the past 45 years I have sailed and raced on boats with bolted-on keels without ever having a concern about keel failure. However, these boats were predominantly built in the 70's and 80's by reputable Canadian builders such as C&C, CS Yachts, Hinterhoeller and Tanzer. I have never heard or read that any boat from these builders has had a keel fall off, despite facing extreme weather and racing conditions, including the 1979 Fastnet Race. Yes, I am aware that a few models which C&C designed and produced in the mid- to late-80's had concerns with bedding integrity of SOME of their keel bolts, as a result of cost-saving choices for filler material in narrow parts of the hull-keel flange, but none of those keels ever failed. They simply needed to have those areas cleaned up and rebuilt properly.

The bolt-on keels from that era were structured differently from modern-day mass-production boats. Instead of presenting a rounded, fairly flat bottom onto which a rigid cast-iron structure is bolted, those past builders actually went through the more labour- and cost-intensive process of moulding a hull with a proper bilge and a keel stub projecting down from the bottom of the boat. Even with the more modern-looking bottom profiles, such as on a CS-30, there is a moulded keel stub. These stubs were laid up with reinforced fiberglass cross-sections much thicker than the rest of the hull and further reinforced with Lyasil bundles (or similar material) at the points where keel bolts came through. This is a much more robust structure that the vaunted internal grids used by modern mass manufacturers. In the event of a grounding, the shock load is carried through the entire hull/keel flange and then distributed through the entire hull, as opposed to severe point-loading of the hull at the front or back of the keel casting, which is what happens when you bond a narrow rigid component (the keel) to a flat section of a flexible component (the fiberglass bottom).

All of this has simply been a long-winded way of pointing out that not all bolted-on keels are the same, in either structure or vulnerability, and that not all encapsulated keels are inherently bullet-proof. If you made it this far, my thanks for your patience. Fair winds and calm seas to you!
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Old 22-01-2022, 13:41   #7
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Re: Amel SM - Bolted on keel?

Its not like a beneteau or jeanneau or hunter type bolted on keel, its more like bolted on ballast. There is a keel stub thats part of the boat which contains the water tankage, and the c drive. Then there is an iron keel section bolted to the keel stub, with bolt access in the water tanks. This iron keel is the winged section if you have ever looked at an sm keel. It needs to be epoxied and barrier coated well, because they can and do rust out especially on bottom where most keels are neglected.
I have heard of only one sm to lose this iron keel in a grounding, the boat survived to be severely damaged on 2 other occasions. An unlucky boat, but most other boats wouldnt survive 3 severe incidents and still be repaired and sailing

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Old 22-01-2022, 15:42   #8
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Re: Amel SM - Bolted on keel?

You don’t need the keel to fall off to have a serious problem. The cost of repair can be substantial. Rust streaks might be cosmetic or a sign it’s time to pull bolts or drop the keel...the cost can be only part of the problem. What do you do if the separation is limited ...you just try a patch or do you risk damage to the hull by dropping the keel which can involve a lot of wedging and torn laminates.
We have never been a fan of steel keels. Rust locks up the bolts and dropping the keel becomes major surgery. When boats were wood with lead keels and bronze or monel bolts and no 5200 was used, dropping the keel was not a horror show.
Steel was less expensive than lead and nobody fooled themselves thinking the two materials were equal.
Rust may be the poor mans’ loctite but it’s the boatbuilders nightmare.
Happy trails.
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Old 22-01-2022, 18:13   #9
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Re: Amel SM - Bolted on keel?

Quote:
Originally Posted by Caleb_Grey View Post
Its not like a beneteau or jeanneau or hunter type bolted on keel, its more like bolted on ballast. There is a keel stub thats part of the boat which contains the water tankage, and the c drive. Then there is an iron keel section bolted to the keel stub, with bolt access in the water tanks. This iron keel is the winged section if you have ever looked at an sm keel. It needs to be epoxied and barrier coated well, because they can and do rust out especially on bottom where most keels are neglected.
I have heard of only one sm to lose this iron keel in a grounding, the boat survived to be severely damaged on 2 other occasions. An unlucky boat, but most other boats wouldnt survive 3 severe incidents and still be repaired and sailing

Will you explain this in detail?
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Old 22-01-2022, 18:15   #10
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Re: Amel SM - Bolted on keel?

Stick with manateeman,60 yrs in the trade my self ,long before grp was the way to go iron keels were common on wooden yachts ,even concrete with steel punching on some home built beauty’s,all were manageable with the correct maintenance ,cast lead with monel bolts and plenty of them was the gold standard and still is for a bolt on keel , encapsulated keels rely on the out side sheaving ,thick or not a grounding will soon chew thriogh it .⚓️⛵️��
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Old 22-01-2022, 22:55   #11
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Re: Amel SM - Bolted on keel?

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Will you explain this in detail?
Not sure what you mean? There are 24 bolts in the 4 tanks. Can be a pain to access the cleanouts, one is under fridge and one is under washer, and i think one is under aft settee in saloon, sucks if there is a freezer under seat.
I would look on amelyachtowners.groups.io
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Old 24-01-2022, 06:28   #12
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Re: Amel SM - Bolted on keel?

To me this is simply about numbers. It's like saying more people crash in Ford f-150 trucks so they must be inherently more dangerous. They probably crash more simply because there are more of them on the road. This is the same for bolt on keels. Given the number of companies making them and the number of boats these companies make of each of their models of course there are more issues and you are going to hear about more of these issues.

But if we reverse that thinking and consider how few you hear of and the reasons for that failure it works the opposite way on your thinking where given the massive majority of boats sailing the ocean have bolt on keels and the minute number that have had issues and why are they really any more dangerous than the other keel types. We can discuss why boats are lost for a great deal of time and find that the keel failing is probably far down the list of things you should consider.

It was reported in one outlet some years ago that home built metal boats were by far the most likely to drop their keels into the deep blue. Again this is probably a percentage based upon playing with numbers.
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Old 24-01-2022, 07:29   #13
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Re: Amel SM - Bolted on keel?

correct , its a tiny proportion out of the 100 of thousands, and if you exclude the ones from faulty individual workmanship , incorrectly repaired or damaged , the underlying fact is bolt on keels are reliable, safe and effective. The fetish of denouncing them is just that
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Old 24-01-2022, 07:56   #14
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Re: Amel SM - Bolted on keel?

I used to have a Pearson Vanguard, an encapsulated ballast keel.

At the time I thought it was miraculous, no keel bolts to fail.

On the mailing list for sisterships, I was a made aware of a few examples of ballast shifting loose in the cavity and the boats being totalled. Made me think about overworked boatyard employees trying to do that layup, reaching down into a deep narrow mold, are they really getting those ratios of glass to resin right? In the case of the Vanguard, owner observations implied they'd also throw whatever they could come up with to take up room between the fiberglass and the lead (foam, concrete, etc.). Out of sight out of mind, at least!

I believe there are threads here of similar "What the hell do I do now" problems with encapsulated ballast shifting. Cast iron ballast getting moist and rusting + expanding is another failure mode, stay away from that!

Now my vote for attachment is two longitudinal rows of bronze bolts in lead ballast. Or stainless, but you may start wondering about crevice corrosion and things like that... after 30 years or so.
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Old 25-01-2022, 16:56   #15
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Re: Amel SM - Bolted on keel?

“Fetish” ? The manatee crew thought you meant“Feta” like Feta Cheeze Pizza.
That was truly disappointing. It was close to dinner time.
They wanted to count all the posts asking for help with cracks between bolt on keels and hulls. Then there all all those who suffer from cardiac arrest when they get the estimate to drop the keel and or fix the bolts.
They actually feel sorry for owners of bolt on keel boats who have no idea that bumping the bottom might wipe out their cruising budget.
You need not loose the keel to sink.
Captain Mark who will be glad to show you how to build a structurally sound vessel. All you need is a sufficient pizza and beer for my crew.
Happy trails.
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