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Old 01-06-2014, 20:35   #496
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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Originally Posted by downunder View Post
I did indicate reasonable weather and I think your suggestion of chemical and bio hazards is a bit over the top.

Can we be sure a body is not trapped in the hull without inspection? One of the photos of the damaged hull showed reasonable dynamic water conditions to me. Then again neither of us are out there.

Obviously you would not do such a penetration alone without a backup diver but if the vessel is still floating it is doable.

No point here in debating dive experience other than to say I also have had experience in a range of water conditions. Would I do it if I was there. Yes.

Cheers
A USCG vessel, constantly trained in emergency rescue and recovery situations, was on site, tasked to this particular wreck. They put a swimmer in the water. The situation was assessed. The decision was made by competent professionals on site, on board and in the water not to penetrate the wreck. Reason enough, beyond what is obviously a dangerous environment swept and rolled by ocean waves (when is it likely that the mid latitudes of the North Atlantic surface will not be so??), with the continual possibility of the sudden sinking of an unstable wreck, to not be Monday morning quarterbacking from shore, no?

Or do you think they spent days searching at great expense, and while actually on site, standing by with the wreck present, the dive teams and deck officers simply said to themselves: "Meh..." ?

Shame they didn't have you on board to show them all how it is done, eh?
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Old 01-06-2014, 21:15   #497
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

Was not that the original vessel that located Cheeki Rafiki in bad conditions and the search was subsequently called off?

Clearly they made the call at the time in the particular conditions and their freediver made the assessment and they left. No issues here. No criticism of what that USCG vessel did or their competence. Under lousy conditions it's a fair call.

Under reasonable weather conditions what's the problem.

I was under the impression and I could be wrong that the search was subsequently restarted after lobbying? Did other vessels subsequently locate it?

Further if someone was to salvage it they would have to have someone in the water.

It appears we are speculating and diving from our armchairs about the cause of keel loss and potential fix. A salvaged hull although now highly unlikely would help.

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Old 09-06-2014, 15:53   #498
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

I haven't seen that particular wreck, so I don't know how dangerous it is to dive on. They do vary.

It did seem odd to me that after all the expense of finding it, more wasn't done to look it over. One would think that 0.01% of what was already spent would have been enough to fund a closer look.

If it was too dangerous for divers, then an ROV would have been a logical choice of equipment for a better view.

I for one would like to have a better understanding of how the keel came off. It would help me to make better decisions when considering the purchase of used sailboats. Conjecture only carries me so far.
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Old 09-06-2014, 17:19   #499
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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If it was too dangerous for divers, then an ROV would have been a logical choice of equipment for a better view. .



Unfortunately , ROVs cannot be deployed into, or near other structures near to the surface (or splash zone) as the wave-induced difference in movement between the ROV and the structure/hull would demolish the ROV.



For information:

ROVs are typically fixed to a launch and recovery system (LARS), which contains the actual winch-deployed umbilical, until it is close to its area of operation, far from direct influence of the surface motion. At that point the ROV detaches from the LARS and operates without an influence from surface vessel, it is then only connected via the power/control umbilical. The LARS is directly connected to the vessel via a constant-tension winch which dampens some of the wave action. The much-heavier armored cable between the LARS and the vessel is spoiled onto the winch on the vessel. This way, the ROV only has to pull a much lighter 'neutrally buoyant' umbilical around with it.



However, I agree that it's a shame that the hull wasn't investigated further once all of that effort was used to locate it.
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Old 09-06-2014, 17:57   #500
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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Originally Posted by pbiJim View Post
I haven't seen that particular wreck, so I don't know how dangerous it is to dive on. They do vary.

It did seem odd to me that after all the expense of finding it, more wasn't done to look it over. One would think that 0.01% of what was already spent would have been enough to fund a closer look.

If it was too dangerous for divers, then an ROV would have been a logical choice of equipment for a better view.

I for one would like to have a better understanding of how the keel came off. It would help me to make better decisions when considering the purchase of used sailboats. Conjecture only carries me so far.
Any wreck floating at or just below the surface with a bunch of rigging (standing and running) hanging in the water column is a serious hazard to a diver. Same goes for an ROV. The wreck is bobbing around and can cause serious injury. Entanglement is a huge risk. No one should question the diver or the supervision decision not to penetrate the wreck. It would be too dangerous for little or no gain.

Regarding concern about a used boat I would submit that you would be better served by examining the used boat yourself. Also, there are naval architects and engineers that will be happy to advise you about keel design and attachment requirements. Of course they expect to be paid for their advice but it is not usually prohibitively expensive. I agree that you should not base any conclusion on the massive amount of conjecture here and on other web sites. Even so I will make one small conjecture that even a close examination of CR would likely not reveal what event or events caused the keel to be ripped off. It obviously didn't just "fall off" as others have speculated. Something unknown and massive damaged that boat. In other words "stuff happened" and my belief is there is no way to know what it was or whether any yacht could have survived it.
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Old 10-06-2014, 19:18   #501
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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The photo posted above of the keelboats in the bilge don't seem to match the pattern of the keelboat holes in the upturned hull. There is a section of the photo of the upturned hull where I would expect to see holes where there are none at all.

I also believe that the size of these keelboats look grossly inadequate and I would have expected them to be at least double the diameter of those shown.

The pattern is consistent for a first , ie (FWD to Back ) 1-1-2-2-2-1 , 9 bolts in all.

I do not see where you get the comment on the diameter. Clearly the vast majority of first are not loosing their keels, even though they often race in very heavy weather with big crews and stressed systems.

Looking at the high res pictures the aft bolt ( which is under the engine m if I remember and very hard to verify ) was severely corroded and may have already failed previously, the fwd two sheared , and then the 3 pairs ultimately tore their way through the hull ( taking a fair bit of glass with it. )

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Old 10-06-2014, 20:34   #502
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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Originally Posted by goboatingnow View Post
The pattern is consistent for a first , ie (FWD to Back ) 1-1-2-2-2-1 , 9 bolts in all.

I do not see where you get the comment on the diameter. Clearly the vast majority of first are not loosing their keels, even though they often race in very heavy weather with big crews and stressed systems.

Looking at the high res pictures the aft bolt ( which is under the engine m if I remember and very hard to verify ) was severely corroded and may have already failed previously, the fwd two sheared , and then the 3 pairs ultimately tore their way through the hull ( taking a fair bit of glass with it. )

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If this is the case, why is there a hole all the way through the hull several feet from the keel?
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Old 10-06-2014, 20:34   #503
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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Originally Posted by goboatingnow View Post
The pattern is consistent for a first , ie (FWD to Back ) 1-1-2-2-2-1 , 9 bolts in all.

I do not see where you get the comment on the diameter. Clearly the vast majority of first are not loosing their keels, even though they often race in very heavy weather with big crews and stressed systems.

Looking at the high res pictures the aft bolt ( which is under the engine m if I remember and very hard to verify ) was severely corroded and may have already failed previously, the fwd two sheared , and then the 3 pairs ultimately tore their way through the hull ( taking a fair bit of glass with it. )

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The area aft of the 2 forward bolts initially looked to me to be the inner hull lining and I could not see any sign of bolts having ripped through. On looking at it closer now I think this is just green seawater and the whole section of glass is gone.

My comment about the diameter of the bolts - the Farr that I race on has keelboats at least 3 - 4 times the diameter of the ones on this First 40 which is why I think these failed ones are grossly inadequate. The fact that one has seriously corroded through, 2 others at least had sheared off and the others had just ripped out due to a possible combination of small diameter keel bolts coupled with inadequate sized backing plates to spread the load I believe well and truly justifies my statement.

I know that there are a lot of First 40's doing serious ocean races and they have not lost their keels but it would be prudent for owners to pay close attention to these keelboats and I personally would at the very minimum increase the size of the backing plates if I owned one.
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Old 10-06-2014, 20:42   #504
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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If this is the case, why is there a hole all the way through the hull several feet from the keel?

This would have been a through hull seacock wouldn't it?
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Old 11-06-2014, 01:00   #505
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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No point here in debating dive experience other than to say I also have had experience in a range of water conditions. Would I do it if I was there. Yes.

Cheers
The experience is not the issue. You can count those divers had the skils for the dive but the real reason is they are at work and not allowed to endanger their lives. Get an amateur and they aren't bound to OSHA or any other regulation concerning work.
Same happened last winter with the recovery of the dead divers in Norway..
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Old 11-06-2014, 01:16   #506
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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The experience is not the issue. You can count those divers had the skils for the dive but the real reason is they are at work and not allowed to endanger their lives. Get an amateur and they aren't bound to OSHA or any other regulation concerning work.
Same happened last winter with the recovery of the dead divers in Norway..
You have expressed my intent better than I.

I have years ago recovered bodies out of a vehicle at night in a river for the local Police.

Theseday under OHS regulations they would wait until they fly in a specialist dive team at great cost to do a very simple job the next day.

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Old 11-06-2014, 02:51   #507
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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Originally Posted by Ozbullwinkle View Post
The area aft of the 2 forward bolts initially looked to me to be the inner hull lining and I could not see any sign of bolts having ripped through. On looking at it closer now I think this is just green seawater and the whole section of glass is gone.

My comment about the diameter of the bolts - the Farr that I race on has keelboats at least 3 - 4 times the diameter of the ones on this First 40 which is why I think these failed ones are grossly inadequate. The fact that one has seriously corroded through, 2 others at least had sheared off and the others had just ripped out due to a possible combination of small diameter keel bolts coupled with inadequate sized backing plates to spread the load I believe well and truly justifies my statement.

I know that there are a lot of First 40's doing serious ocean races and they have not lost their keels but it would be prudent for owners to pay close attention to these keelboats and I personally would at the very minimum increase the size of the backing plates if I owned one.

The bolts on the first are either M22 or M20. To suggest that they should be M60 or M80 is quite ridiculous , there isn't enough material across the Keel for that

Many 1000s of first have been made in various guises. The vast majority are fine and many have many bruising deep sea races to their credit.

In my view , cheeki was an old boat, very very extensively raced, it's was in effect 3 to 4 times it's real age, I suspect there either existing damage, incorrectly refitted keel or so e combination of pre-existing damage. It was unfortunate that the 4 men in question happened to be the ones to be there when the time ran out.


This is no a failure of a series , this is a specific failure on a specific boat


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Old 11-06-2014, 04:15   #508
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UK yacht Cheeki Rafiki missing in mid-Atlantic

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Originally Posted by goboatingnow View Post
The bolts on the first are either M22 or M20. To suggest that they should be M60 or M80 is quite ridiculous , there isn't enough material across the Keel for that

Many 1000s of first have been made in various guises. The vast majority are fine and many have many bruising deep sea races to their credit.

In my view , cheeki was an old boat, very very extensively raced, it's was in effect 3 to 4 times it's real age, I suspect there either existing damage, incorrectly refitted keel or so e combination of pre-existing damage. It was unfortunate that the 4 men in question happened to be the ones to be there when the time ran out.


This is no a failure of a series , this is a specific failure on a specific boat


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I have already agreed that there are a lot of Firsts doing serious ocean races that have not lost keels. But say you owned a First 40 and on checking the keel you found some degradation in the bolts would you be tempted after knowing of the fate of CR to reinstall the same diameter bolts or would you consider larger ones? I know what I would do.

I am not saying that M60 or M80 would be practical for the First but if one looks at the photos in post #460 there is plenty of keel material either side of the existing bolts to accommodate larger diameter bolts. When one looks at the size of the nuts on the bolts shown in the 2nd photo, these really bring home how small in diameter these keelbolts are. These nuts are not what one would expect to see on a yacht that was going to be campaigned as a serious ocean racer.
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Old 11-06-2014, 04:58   #509
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

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I am not saying that M60 or M80 would be practical for the First but if one looks at the photos in post #460 there is plenty of keel material either side of the existing bolts to accommodate larger diameter bolts. When one looks at the size of the nuts on the bolts shown in the 2nd photo, these really bring home how small in diameter these keelbolts are. These nuts are not what one would expect to see on a yacht that was going to be campaigned as a serious ocean racer.

The first series, like many racer-cruisers, and unlike cruiser- racers are designed to be competitive at handicapped racing events. Hence they are designed with very high aspect keels, shallow canoe bodies with low wetted areas and any unnecessarily weight is stripped out. The result is a vessel with very small , if almost non-existent bilges and a difficult keel connection.

In many high end vessels this was solved by interior metal grids etc, but notably even x-yachts had to abandon that in favour of carbon-fibre grids to remove weight so as to stay competitive.


Racing ability is typically what these vessels are bought and the design decisions, material, weight,costs are a typical compromise to engineer a fairly low-cost competitive racer- cruiser. In fact the compromises in the first series are more abrupt then in dedicated racers like say the Archambault A40.

Simply boiling this down to the stud diameter is misplaced. strength or durability is simply not a function of making things bigger.

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Old 11-06-2014, 05:26   #510
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Re: UK yacht Cheeki Rafiki missing in mid-Atlantic

Earlier on it was reported that these bolts are not stainless but rather galvanized steel bolts. Thus they can easily be stronger than stainless for a given diameter. But galvanized bolts require vigilance to ensure they don't live in sea water. If the keel to hull joint leaks then corrosion is going to eat away at the zinc in the galvanization layer. Periodic inspection and maintenance are needed. No keel attachment is maintenance free but this type probably warrants religious inspection.

Steel/fiberglass interfaces like this require engineering. Making changes to the design should only be done if the same engineering goes into the redesign. It is not difficult for non-engineers to make a change they believe strengthens a structure only to find that in fact it made the whole thing less so.
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