Cheeki Rafiki MAIB report published

JimC

Not actually an anarchist.
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South East England
This is from the MAIB Safety flyer on the incident (attached)

Narrative

On 16 May 2014, an alert was received from the personal locator beacon of the skipper of the United Kingdom (UK) registered yacht Cheeki Rafiki, which was on passage from Antigua to the UK, and located approximately 720 miles east-south-east of Nova Scotia, Canada. Despite a major search effort, during which the yacht’s upturned hull was located but not recovered, Cheeki Rafiki’s four crew remain missing.

In the absence of survivors and material evidence, the causes of the accident remain a matter of some speculation. However it is concluded that the yacht capsized and inverted following a detachment of its keel. In the absence of any apparent damage to its hull or rudder other than that likely to have been directly associated with keel detachment, it is concluded unlikely that the vessel had struck a submerged object. Instead, a combined effect of previous groundings and subsequent repairs to its keel and matrix had possibly weakened the vessel’s structure where the keel was attached to the hull. It is also possible that one or more keel bolts had deteriorated. A consequent loss of structural strength may have allowed movement of the keel which would have been exacerbated by increased transverse loading through sailing in worsening sea conditions.

Safety Lessons

1. Matrix detachment is possible in yachts where a GRP matrix and hull are bonded together. The probability of this occurring will increase with longer and harder yacht usage. There is therefore a need for regular structural inspection by a nominated competent person as part of a formal verifiable procedure, as well as before embarking on an ocean passage.

2. Owing to the continuous nature of a matrix where solid floors are in place, particularly where the keel is attached to the hull, it may be difficult to readily identify areas where a detachment has occurred. There are differing opinions among surveyors and GRP repairers with regard to what are appropriate methods of inspection and repair, including the circumstances in which the keel should be removed. There is therefore a desire for best practice industry-wide guidance to be developed.

3. Any grounding has the potential to cause significantly more damage than may be subjectively assessed or visually apparent, including matrix detachment. It is therefore important that all groundings, including those perceived to be ‘light’, result in an inspection for possible damage by a suitably competent person.

4. Ocean passages require comprehensive risk assessment and contingency planning. A compromise needs to be made between planning a high latitude route, to pick up favourable winds and ensure a speedier passage, and a low latitude route, to avoid particularly adverse weather at the expense of a slower passage possibly necessitating additional port calls. Weather routing, vessel tracking and frequent communications from a shore-based support cell can significantly reduce the risks.

5. Attached keels are a feature of modern yacht design. Operators and crews therefore need to be aware of the associated danger of keel detachment, and have preventive procedures in place to reduce the risk, e.g regular inspection of the keel attachment area and checking of keel bolts, and documented actions to take in the event of flooding, including reducing the load on the keel and preparing for the yacht capsizing and inverting.

6. Search and Rescue mid-ocean is hampered both by the time it takes fixed-wing search aircraft to arrive and their ability to assist when on scene. Consideration therefore needs to be given to how the alarm will be raised, both by the quickest means and with an accurate position. Wearing a Personal Locator Beacon provides additional assurance that the alarm can be raised if it has not been possible to deploy the vessel’s EPIRB.

7. It is likely to take many hours or even days before SAR assistance can be provided midocean, during which time being able to board a liferaft will be key to survival. In small craft there will be a trade-off between positioning the liferaft so it will deploy automatically in the event of an emergency, and the risk of it deploying accidentally in heavy weather. Whatever solution is chosen, for long passages it might be necessary to make other compromises to ensure that the liferaft is located in the best possible position to ensure its availability in the event of a catastrophic event, such as a sudden capsize.

SafetyFlyerToMAIBInvReport08-2015_CheekiRafiki.pdf

 

Attachments

  • SafetyFlyerToMAIBInvReport08-2015_CheekiRafiki.pdf
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us7070

Super Anarchist
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i'm part way through the report.., so maybe all will be explained.., but i'l ask my question anyway...

is what they call the "matrix" what some of us refer to as a hull liner?

it looks that way from the picture in the report.

 

Remodel

Super Anarchist
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i'm part way through the report.., so maybe all will be explained.., but i'l ask my question anyway...

is what they call the "matrix" what some of us refer to as a hull liner?

it looks that way from the picture in the report.
I'm not sure, but since they refer to the GRP matrix as bonded to the hull, I infer that to be a reference to the floor members and structural grid that supports the keel and rig loads. I do not think it refers to the liner.

I could be wrong...

 

ProaSailor

Super Anarchist
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Fig_1.jpg


Fig_12.jpg


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Fig_19.jpg


 

kent_island_sailor

Super Anarchist
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Kent Island!
3. Any grounding has the potential to cause significantly more damage than may be subjectively assessed or visually apparent, including matrix detachment. It is therefore important that all groundings, including those perceived to be ‘light’, result in an inspection for possible damage by a suitably competent person.

That will do wonders for insurance rates. Some years I would be running an inspection a month :eek:

3.1. Quit building fragile boats :rolleyes:

 

Patrick Shaughnessy

New member
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I just wanted to say to the group here, that we assisted in the MAIB investigation, but were unable to review a draft of the document before it was published. I think there a few inconsistencies in the report, but on the whole it is a well written document.

The report does indicate that prior groundings were repaired in an unknown way. Just to be 100% clear, at FYD we have no knowledge of the Beneteau dealer recommended repair procedure. That by itself is a pretty worrying. Even if that was followed, we don't necessarily know that it would be sufficient.

We take safety very seriously and will issue an announcement/addendum to the MAIB report with some other considerations. The biggest thing I want to emphasize is, please contact your yacht designer if you have any questions. If you have an incident that potentially caused structural damage, contact your yacht designer. If you have an impending repair contact your yacht designer.

In this particular instance the hull liner laminate (do not call it a matrix), is not a trivial simple laminate. Replacing it with some unknown laminate to similar thickness would not necessarily be adequate. Please ask first. It almost incomprehensible that a repair could be made in a critical area like this without guidance. Please let us help you.

We will be back with more, after we've had a chance to fully digest the report. Stand by.

Patrick

 

Innocent Bystander

Super Anarchist
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Lower Southern MD
3. Any grounding has the potential to cause significantly more damage than may be subjectively assessed or visually apparent, including matrix detachment. It is therefore important that all groundings, including those perceived to be ‘light’, result in an inspection for possible damage by a suitably competent person.

That will do wonders for insurance rates. Some years I would be running an inspection a month :eek:

3.1. Quit building fragile boats :rolleyes:
With respect for the lost crew, I'm concerned if anyone thinks it is acceptable for a production racer/cruiser to be designed and constructed in a way that grossly normal useage may require a significant inspection regime and designer consultation on a regular basis. A custom GP boat? Perhaps.

Agree with 3.1.

 

Bryanjb

Super Anarchist
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I don't see a whole lot of strength in that design and using splooge to hold the pan to the liner is a punters game. Worst of all there is no way to check the condition of the splooge holding the bits together after a grounding.

 

Scrotal Canoe

Member
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0
Where would a person- Owner, Skipper, Crew Boss, even crew, report groundings? Most boats through the years I have raced on bumped the bottom short tacking the shore line to stay out of the current. When I experienced this, reporting it to whoever would seem silly. I have been on boat deliveries when some dumb ass thinks he knows what he's doing and smacked, rocks, sandbars, log booms so hard it actually sent me flying when down below. While off watch sleeping, a violent awakening. These groundings are reported to the Owner, if there is at least one crewman aboard with any respect for seamanship.

Who or what entity should serious groundings be reported to?

 

Raz'r

Super Anarchist
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It almost seems to me you'd need a yard that has a NA on retainer.

And sailboat owners are cheap....

 

DDW

Super Anarchist
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I just waded through the whole thing.

It is a bit worrying that Beneteu had a service bulletin detailing how to repair a detached matrix in this boat, and that the MAIB had no trouble finding multiple instances to look at, and multiple repair examples to study.

I would not want to own a boat with this method of construction. It is brittle, and has no means of inspection for manufacturing or damage related faults.

Regarding grounding, this was a charter boat with a hired captain. No charterer ever describes any grounding as other than "light", nor I suspect, does any hired captain.

 

kent_island_sailor

Super Anarchist
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Kent Island!
This is how airplanes are operated (in theory). An overstress/overspeed is logged and leads to big $$$ inspections and NDT.

Almost no boat owners would be willing to pay for this kind of thing.

 

us7070

Super Anarchist
10,226
241
so, it seems like the GRP hull in the area of the keel is solid laminate

the liner (matrix) is apparently made in a similar fashion as the hull, so i am assuming it is also a solid GRP laminate - although Patrick Shaughnessy from FYD might be implying in his post above that there is something special about the construction of the liner...

the two pieces are glued together, but if the glue fails - which is known to happen after some groundings - the liner can move wrt the hull, and this movement can weaken the structure somehow allowing the keel to fall off.

clearly relative movement could lead to the keel bolt holes enlarging, and maybe some other holes forming, allowing water ingress

there is not much detail about exactly why the keel falls of - i could imagine a few scenarios..., but i am surprised they didn't speculate a bit more about this

so, one thing i have always wondered about this type of build.., is why the keel bolts only go through a "bay" of the liner, and not through the beams which are also part of the liner, and cross the keel...

this seems to me like it would be much stronger, as it would do a better job of distributing the keel loads over a large area than simply having backing plates on the liner bay.

Patrick - can you comment on this?

 
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