Members' Online Book: Lessons from Losses at Sea, Chapter 5 of 5

“Cheeki Rafiki” Report Misses An Opportunity to Make Boats Safer

MAIBInvReport_8_2015-1_250I would be the first to commend the authors of the report on their diligence in analyzing the capsize of the Beneteau First 40.7 Cheeki Rafiki and the tragic loss of four lives.

Having said that I believe said report failed the offshore sailing community in its recommendations.

Let’s summarize what I concluded from the report and then look at the steps I believe that we should take to at least reduce the chances of another sudden keel loss tragedy.

Not The Builder’s Fault

The designer and builder of Cheeki Rafiki were at least reasonably diligent…when measured against prevailing standards. That last clause is in bold for a reason that will become apparent later.

…Farr Yacht Design Ltd was guided by the existing American Bureau of Shipping (ABS) classification society rules when completing this particular area of its design and associated calculations.

All materials used in the construction process were tested in Beneteau’s laboratory prior to entering the manufacturing process. These included all adhesives, resins, glass fibres and metals.

(All the quotes, unless otherwise attributed, are from the report.)

The point we need to understand here is that builders like Beneteau operate in a very price competitive market and therefore we can’t reasonably expect that they will spend money out of their profit margin to increase the strength of their boats over and above the minimum industry standards, both prevailing by current custom and required by legislation—beating on builders like Beneteau is not going to help.

As an aside, but an important one, readers with a technical bent may wish to also read the Annexes to the report and particularly the part prepared by the Wolfson Unit, starting on Page 13, which includes drawings of the first 40.7 keel attachment area.

Said Wolfson report does state that while Cheeki Rafiki complied with ABS standards the boat would not have passed the newer ISO 12215-9.

Having said that, in my opinion the differences between the two standards are not material, as least when applied to my conclusions below.

Not The Crew’s Fault

It is clear from the report, at least to me, that the crew were competent, well trained and probably performed well.

Those who have second guessed this crew and suggest that they should have done more to find the leak have simply not been offshore in a small sailboat in the kind of conditions prevailing before the accident.

In my opinion, Cheeki Rafiki failed the crew, not the other way around.

Not The Weather

MAIBInvReport_8_2015 Grib

There is no question that the weather at the time of the keel failure was nasty and that the crew and shore personnel were being aggressive in their routing, but even so the boat encountered nothing worse than any boat crossing the North Atlantic can easily be subjected to and should be ready for.

ISO 12215-9 defines Design Category A as: ‘category of craft considered suitable to operate in seas with significant wave heights above 4m and wind speeds in excess of Beaufort Force 8, but excluding abnormal conditions such as hurricanes.

With reference to the hindcast weather data for 0300 on 16 May 2014, it is concluded that Cheeki Rafiki was operating within its design category criteria at the time of its loss.

Not The Safety Equipment

Sure, some of the safety equipment on Cheeki Rafiki was not the very best available or installed in the very best way. The report spends a lot of pages on this (rightly so), but really, based on my experience, said equipment and installation wasn’t that bad either.

And the point we should not lose sight of is, that if a boat experiences sudden keel failure and suddenly inverts far from help in heavy weather, things are unlikely to end well, regardless of safety equipment carried.

The Big Question

Overturned hull of the "Cheeki Rafiki", U.S. Navy photo.

Overturned hull of the “Cheeki Rafiki”, U.S. Navy photo.

So, what happened? Why did these four men die? Well the report does a great job of explaining that. To really understand the contributing factors you need to read the whole thing, but here’s a summary:

Grounding Damaged

Cheeki Rafiki over her life, like any sail training boat, was treated hard with many miles and an indeterminate number of groundings.

Cheeki Rafiki grounded twice in 2007. After each grounding, it was inspected and repaired. The yacht had at least four further groundings; all were described as ‘light’.

These groundings (definitely) and cycle loading while sailing many miles (probably) weakened the keel to hull joint to the point where it failed.

Difficult To Detect

Worse still, the report highlights that because of the type of structure used to take the keel forces, it is difficult to determine by inspection whether or not the keel structure is safe after a grounding.

False indications may be obtained when hammer testing to identify matrix detachment, particularly in the area around the keel washer plates, owing to the clamping effect of the keel bolts and where the rig has been tensioned to cause compression of the matrix/hull attachment.

Inadequate Repair

The keel support structure on Cheeki Rafiki was repaired twice after groundings but it seems likely (since the keel fell off) that repair was not adequate and did not return the structure to original strength.

Further, in my opinion, if a boat has experienced a structural failure due to grounding, not once but twice, as Cheeki Rafiki had, repairs should have increased the strength of the boat over and above original build.

The Fundamental Problem


Typical Beneteau First 40.7 keel bolt arrangement (not Cheeki Rafiki)

Easy To Damage

The loss of Cheeki Rafiki is just the tip of the iceberg. Several of her sister ships have suffered from the same problems. The fundamental issue seems to be that these boats rely on a structural liner to take the loads of the keel. The matrix—as it is called throughout the report—is fabricated outside of the boat and then glued in.

Now I understand that modern adhesives are incredibly strong, but clearly something is wrong. Over and over again we see boats with this construction technique suffer separation of the matrix from the hull in a grounding as well as damage to the laminate in the way of the keel bolts.

During the course of the investigation, the MAIB received much anecdotal evidence regarding matrix detachments on Beneteau First 40.7 yachts. Areas notable for detachment were in the forward sections of the matrix, commonly attributed to the vessel slamming, and the area around and aft of where the keel is attached to the hull, commonly attributed to the vessel grounding.

Difficult to repair

And it gets worse. Not only do these boats get damaged easily in a grounding or even from just hard sailing, it’s almost impossible to fix them properly at a reasonable cost. I won’t burden you with the details of why that is here—you can read them in the report.

Not just Beneteau

And such problems are not limited to the First 40.7. Here is an example of a modern Swan that suffered detachment of the matrix due to adhesion failure from a grounding.

In this case the repair was worth doing to this multi-million dollar boat but clearly it’s not a viable answer for a (relatively) inexpensive production boat since said repair (done right) to the Swan cost more than a second hand First 40.7 is worth.

So let’s summarize. We are building boats and classing them as ocean capable that:

  • Will be dangerously damaged by something we know happens frequently: grounding.
  • Said damage can’t be reliably detected and accessed with practical methods that are readily available.
  • Said damage can’t be properly repaired to original strength at a cost that makes sense in relationship to the value of the boat.

Report Recommendations

Up to this point, I think the report did a great job of analyzing a complex situation in the best way possible. But, in my opinion, the recommendations section is an epic fail.

Said section concentrates on improvements to:

  • crew training,
  • boat inspection and application of commercial classes (different from construction classes),
  • life-raft deployment,
  • and raising the awareness of the dangers of grounding this type of boat.

There is not one recommendation in the report relating to improving the strength of keel to hull attachments.

An Aircraft Analogy

To me this approach is analogous to an aircraft accident investigator saying:

We have identified that the wing spar will be damaged by an incident that typically happens several times over the aircraft’s life—say heavy turbulence—and that said damage results in high risk of the wings falling off, not only on this aircraft, but also on many, perhaps most, aircraft with this kind of wing spar construction.

Further, we have determined that there is no practical way to accurately determine when this type of wing spar damage has occurred or how extensive it is and that repair to the structure to original strength is problematic.

Therefore, we are recommending that flight crew training be improved, particularly in the area of identifying the cracking sound that comes just before failure and also in using the escape hatches and parachutes after the wings fall off.

Further, the wing spar should be inspected more frequently, even though we have already determined that it is difficult to detect whether or not said spar has been damaged.

Seriously, what I have outlined above, using an aviation metaphor, is exactly the way I read the Cheeki Rafiki report.

Safety of Flight

But I didn’t use the aircraft metaphor just to make a point. Rather I believe we need to borrow a concept from aviation safety:

In the design of aircraft, certain machinery and equipment is in a separate category, “safety of flight”. These items must be absolutely reliable and must be capable of enduring the worst environment that the aircraft may encounter. –Don Jordan, aircraft designer and inventor of the Jordan Series Drogue

Of course, in a perfect world, many parts of a boat would be so classified, but that’s not practical because boats would end up being as expensive as planes.

So we must strike a balance with, as I argued in my original article on this tragedy, keel design and build having the “Safety of Flight” standard applied because, if a keel falls off, particularly offshore, fatalities are much more likely than with most any other hull or rig failures.

John’s Recommendations

OK, I have been pretty negative in the last few paragraphs. And I’m a firm believer that if you are going to criticize the hard work of others, you had better be willing to at least take a stab at making things better.

So here are my recommendations based on the findings of the report:

  • The keel attachment construction technique used on Cheeki Rafiki—glued in matrix—is, in my opinion, fundamentally flawed and should be specifically banned under classing regulations like ISO and ABS.
  • These scantling regulations must be upgraded so that the keel to hull attachment will maintain integrity in a hullspeed grounding and also withstand pounding and slamming while sailing over the life of the boat.
  • Said upgraded scantlings should be a requirement for Class A (Offshore) classification.

Or to put it another way, I strongly believe that we must return to the time when keel to hull joints were built not only to be strong enough the day the boat was launched, but also to withstand common abuse, such as groundings and slamming up-wind—people make mistakes and safe offshore boats forgive mistakes.

I’m not an engineer, but I suspect that much of the path to returning to the days where a keel loss was unheard of will be to use designs in which the structural members that distribute keel load (floors) are glassed in individually with reinforcing fibres directly to the hull.

The other benefit—that I verified during a wide reaching conversation with the master boatbuilder that repaired the Swan—of this traditional construction method is that grounding damage is immediately obvious and relatively easy to repair to original or better strength at a cost of around 10% to 20% of a proper matrix repair.

What about cost and practicality of my proposed changes to construction standards? Well, that’s the tragic thing. I’m reliably informed that it is perfectly practical to engineer and build a hull to fin keel—yes, even modern deep narrow keels—joint that will withstand multiple hull-speed groundings without serious damage.

And the cost of said upgrade at build of a boat like the First 40.7 would be less than 1% of the original price tag.

Surely preventing more tragedies is worth that much?

It’s Not Personal

One more thing. I need to make clear that nothing in this article should be interpreted as criticism of the investigators and authors of the Cheeki Rafiki report.

Theirs was a hugely difficult job, which they, in my opinion, did well. Who knows, perhaps recommending sweeping reforms of building standards was not an option open to them, for reasons we are not aware of.

Further Reading


I have read the report through with great care several times and based on that effort feel that the above article is a fair and equitable summary and analysis of its contents. Having said that, I could certainly have misunderstood the report in one or more areas. If you spot any such misunderstanding or misinterpretation, please leave a comment, I’m all ears.

One other point. I will delete any comment that makes any accusation of fault in the loss of Cheeki Rafiki. My reason for writing this article was to try and make things better and avoid another tragedy—let’s all stay focused on that goal.

Copyright Acknowledgement

The images and quotes in this article are from Report on the investigation of the loss of the yacht Cheeki Rafiki—UK Crown copyright.

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Meet the Author


John was born and brought up in Bermuda and started sailing as a child, racing locally and offshore before turning to cruising. He has sailed over 100,000 miles, most of it on his McCurdy & Rhodes 56, Morgan's Cloud, including eight ocean races to Bermuda, culminating in winning his class twice in the Newport Bermuda Race. He has skippered a series of voyages in the North Atlantic, the majority of which have been to the high latitudes. John has been helping others go voyaging by sharing his experience for twenty years, first in yachting magazines and, for the last 12 years, as co-editor/publisher of AAC.

48 comments … add one
  • Richard Dykiel Jun 25, 2015, 10:55 am

    Thank you for this outstanding analysis.

    • John Jun 26, 2015, 7:29 am

      Hi Richard,

      Thanks for the kind words.

  • RDE Jun 25, 2015, 12:23 pm

    Hi John,
    Outstanding summary of the type that it is almost impossible for a committee of individuals with different industry connections to produce!
    The only comment I might place different emphasis upon is the tendency toward “modern” keel designs with long lever arms and mounting areas minimized as to width and length. While it may be entirely possible to design a structure to support such a keel reliably after multiple groundings it is much more difficult and thus more expensive. Increasing the mounting base area is the most cost effective way of reducing point load upon impact and thus increasing structural reliability.

    • John Jun 26, 2015, 7:28 am

      Hi Richard (and Nick),

      While I certainly agree that widening the keel root would make the attachment a lot stronger in and of itself, I think it would be a mistake to advocate for a legislated return to more traditional keels since by so doing I think our recommendations would end up being classed as the “rantings of a lot of old fogies” by many, particularly those who race, and so diminish any chance that our recommendations could actually be adopted.

      The fact is that modern keels do provide a big bump in performance and, as Bill Lee is want to say,”fast is fun”. And said keels can be built to withstand a grounding, it’s just more expensive to so, as Richard points out. But if someone wants to have a very high performance boat with a high tech keel, who are we, or the legislators, to tell them they shouldn’t, as long as said keel conforms to a new and more stringent strength requirement.

      Bottom line, I didn’t just write this to entertain, but rather in the hope that it could be one step, no matter how small, on the road to change for the better, and if we are going to see change we need to include all types of offshore sailors including racers.

  • Nick Kats Jun 25, 2015, 2:03 pm

    Look at the pic – the keel was torn off sideways. And look at the keel base (where it meets the hull) – it is far too narrow.

    Widening the keel base will allow keel-hull fasteners to move father apart.

    Doubling the width will make this joint much stronger. Maybe 4x more resistant to lateral forces? (I’m no engineer, am most definitely not qualified to produce a formula giving the ratio of width to strength..)

  • Eric Klem Jun 25, 2015, 4:40 pm

    Hi John,

    I agree completely. When I read the report a while ago, I found it very confusing how the conclusions didn’t seem to be related to the rest of the report. The simple fact of the matter is that you need to do stuff right up front as it is extremely difficult to fix issues fully during repairs. When something is designed and built, a huge amount of analysis goes into making sure that it meets the design requirements. To try to do that after the fact is nearly impossible for the average person and would be prohibitively expensive if a knowledgeable professional was hired. In the case of keels, I think that you need to design them for that worst case grounding load as otherwise you will never be able to truly tell whether it is sufficiently strong once you have had a single grounding.


    • John Jun 26, 2015, 7:32 am

      Hi Eric,

      Thanks for a very clear summary of the fundamental issue. Or to put it another way, being in a situation where we are relying on some boat yard guy, no matter how well meaning and experienced, with a grinder and a bucket of resin to fix a fundamental engineering problem is never going to end well.

  • Rob Gill Jun 26, 2015, 1:00 am

    Hi John – thanks for this important addition to a very readable original report. Two things puzzle me that I would appreciate comment on:

    Firstly, the report mentions their northern route to the UK and outlines reasons why they didn’t take the more usual rum (sic) route via the Azores. But it doesn’t mention the effect on the seas of the Gulf Stream running against the strong head winds forecast (and experienced) in what was foremost a “racing” yacht design. Would the Gulf Stream have been sufficiently dispersed at their longitude to not be a factor and therefore not considered in their report? I don’t have an accurate tidal/current atlas for the North Atlantic (being in antipodes) so it is hard to tell.

    Secondly, there was no comment from the shore-base at the time (or in the subsequent report) to heave-to when the leak was detected, and especially once the keel junction became suspect. It seems from the report they carried on sailing (albeit with reefs) until the keel came off – why was this?
    Surely heaving-to would have helped in finding the leak (kinder motion/attitude), minimised the ingress of water (less water pressure on the hull) and eased the stresses on the keel/hull junction? Heck, we heave-to when I spill my tea!
    Maybe they knew this yacht design couldn’t be made to heave-to and if so, should the report have recommended including “proven ability to heave-to” as a mandatory (or at least strong recommendation) for offshore Cat 1?


    • John Jun 26, 2015, 7:57 am

      Hi Rob,

      You are quite right that their could have been Gulf Stream influence, particularly in generating the big wave that started the problem. I have written more about that here and here.

      And I would also guess that heaving-to may have reduced the load and postponed the tragedy.

      Having said that, my guess is that the keel would still have fallen off before the boat reached England. The point being that I think the structure was, by that time, a ticking time-bomb and if that gale or that wave did not cause disaster, another one would have.

      Also, the key point that I gleaned from reading the report was that the crew didn’t know that the keel was the problem. This may seem hard to believe in hind sight, but, at least to me, is perfectly understandable given that once there was water sloshing around in that shallow bilge it would be near impossible to tell where it was coming from.

      I would also guess that since it was only blowing force 7 (about) at the time of the disaster, the young skipper, trained as he was in the world of UK racing where crews regularly race in winds of that strength and higher, would even think that the conditions warranted heaving-to.

      As to requiring the ability to heave-to, that might be a problem for many high performance boats. Having said that, I do believe we should be requiring a viable and tested storm survival strategy. More ideas on options for that here.

  • Ian Tyler Jun 26, 2015, 5:55 am

    John, thank you for such an erudite analysis. I did read the report a little while ago but hadn’t spotted the obvious omission that you picked up and explained so clearly.
    The picture of the detaching “matrix” in the Swan 45 repair article illustrates the apparent madness of creating a design where the structural integrity of the boat is dependent on a “stick on” extra structure. Especially where this structure is almost completely inaccessible and virtually impossible to inspect without expensive deconstruction of the boat above it.
    As you say – it would appear that this form of construction is fundamentally flawed.

  • Robbie Wilderspin Jun 26, 2015, 8:25 am

    Hi John,
    Thanks for a well worded and concise analysis and set of conclusions. I can say that as it coincides with my own view on the tragedy (but better worded 🙂 ).

    The subject has been much discussed on the UK sailing forums, as you would expect. One aspect that has been talked about there is the idea of NDT examination of structures, much used in aviation and industry generally. It seems there are techniques that can be used to examine delamination in glass fibre structures already in use for yachts. These may lead to to a more cost effective survey techniques for the ‘matrix’ type of construction – though the fix cost is still as high the owner should have a better idea of the risk of failure.


    • John Jun 27, 2015, 7:13 am

      Hi Robbie,

      Thanks for the kind words.

      I absolutely agree that we should be looking at better ways to non-destructive test for damage in the keel to hull joint. In fact I advocated for that in my original article on the subject.

      Having said that, I feel strongly that while NST may help us deal with the huge problem of the existing fleet of boats that are easily damaged in a grounding, said testing should not become an excuse for not dealing with the inadequacy of the existing scantlings requirements for new boats.

  • Matt Jun 26, 2015, 12:47 pm

    By all accounts, Beneteau’s QC was impeccable. And the design was, apparently, in accordance with the relevant codes at the time. Since it failed anyway – not just on this one boat, but apparently on many others – we must conclude that the code itself was flawed.

    I am not ready to outright reject the hull/gridliner architecture, but it does introduce unique new failure modes that must be accounted for. Speculating a bit: Are designers mistakenly assuming that slamming and grounding loads are transferred across the entire bond area of the hull-to-gridliner joint? Unless the skin is almost perfectly rigid (unlikely), there must be substantial peel loading along the edges of the joint.

    I’m honestly not sure what to say about the keel attachment design in this specific boat. Apparently it met the relevant codes, but I have a hard time understanding why anyone would bolt the keel to the hull skin and gridliner lower flange alone. It would seem to create tremendous stress concentrations, which could be avoided with just a bit more structure to link the keel with both the upper and lower flanges of the gridliner.

    Also, why is it OK to hand-wave away problems with the keel joint by declaring it to be a routine maintenance item? Boats run aground all the time. Saying “you must haul the boat and have this structure inspected after a hard grounding (but not after a light grounding)” is equivalent to making the keel joint – a “Criticality 1” item, in NASA-speak – dependent on routine maintenance. Maintenance that, in this case, is expensive, time-consuming, and dependent on someone’s subjective judgment of what is a “hard” grounding. Economic reality rules supreme, and people don’t haul boats “just to be sure” when nothing is obviously wrong with them.

    • John Jun 27, 2015, 7:22 am

      Hi Matt,

      Thanks for the shining the engineering light so well, as always.

      Interesting that you would not write off external matrix use completely. I guess I could only live with that if the designer and builder could really satisfy me that they could execute said technique with 100% consistency and that they had come up with a way for a lay person in the field to easily identify when the joint between the matrix and the hull had been damaged.

      Also, I too wondered how it made sense to fasten the keel bolts through the matrix flange alone.

      And, as you say, expecting people to evaluate a grounding critically and then act on that evaluation appropriately is just plain idealistic idiocy.

  • Victor Raymond Jun 26, 2015, 2:11 pm

    Great article. I once kissed a rock with the Jeanneau SO 45.2 (Jeanneau and Beneteau are virtually the same company.) I did not loose the keel but the resulting damage (about $85,000 worth) was astounding.

    Fortunately for me the surveyor was not going to sign off on the repairs unless the matrix was better than new. Jeanneau makes up the matrix from using wood scraps and whatever to make up the form. After glassing up the limber holes between each section are drilled out but not cored. The factory expects the wood to rot eventually but that the fiberglass is where strength is not the wood core. Hmmm….

    The surveyor would have none of that. The whole matrix was rebuilt with solid timber encased in fiberglass resin. Then the limber holes were cored and drilled so moisture would not be in contact with the wood.

    This obviously made the boat stronger and a bit heavier but worth the effort.
    I wish all surveyors had the same knowledge, experience and guts to do the right thing for current and future owners.

    • John Jun 27, 2015, 7:27 am

      Hi Victor,

      Wow, that’s great information to back up our case for change. Thank you.

    • Matt Jun 28, 2015, 3:22 pm

      “Wood scraps and whatever”? I can’t say I’m terribly surprised, but that’s not OK.

      Maybe I was a bit too charitable in my choice of language earlier. Any design code that does not allow for grounding loads is not worth the paper it’s printed on.

      This boat – this entire class – was structurally flawed by design. The flaws were apparently sanctioned by – and had their roots in – the design codes of the time. Despite being from a famous design office and passing meticulous in-build QC, it failed. Cheeki Rafiki was not an old boat; it was only in its eighth season and had seen a working life to date that was completely within expected norms for yachts of this type.

      The keel attachment shown in Annex D of the report may have been drawn based on the ABS codes of the time, but I cannot imagine signing off on such a design.

      Just because something meets a bunch of codes and regulations doesn’t mean that those codes and regulations are any good to begin with. The Ford Pinto met all the codes of its time. So did the De Havilland Comet. You have to apply good engineering judgment to the code itself as well as to the design; the code cannot be allowed to replace good engineering judgment.

      • Marc Dacey Jun 28, 2015, 4:04 pm

        Matt, I believe that part of the issue is that modern production boats take their design cues and “desirable characteristics” from race boats of the preceding generation. Of course, race boats are tailored for both specific and narrow parameters…and are frequently seen as expendable after very rough, if short, service lives. Cruising boats are just about the opposite in that they are meant to have long, and largely docile, lives with only occasionally materials-testing incidents in the form of sustained heavy weather or hard groundings.

        And yet cruisers are “racier” than ever in terms of keels, lay-up and, it must be said in some cases, robustness of their internal construction. This makes big boats float along in light airs, the sort of weather the local day sailors and club racers enjoy. But it is not necessarily a great idea offshore, an environment which uses up lightly built boats faster than do inshore or coastal waters, on average.

      • John Jun 29, 2015, 7:54 am

        Hi Matt,

        That’s really the whole point isn’t it: The ABS code that “Cheeki Rafiki” and her sister ships where built to has been proven by events to be woefully inadequate and needs to be upgraded using “good engineering judgement”.

        All of the other stuff that is being discussed in relation to this tragedy, both in the report and elsewhere, is simply noise compared to this fundamental issue.

  • RDE Jun 26, 2015, 2:34 pm

    Hi Matt,
    To elaborate upon your comments about design assumptions in hull liner designs I’d add two real world observations:

    1- It is impossible to produce a liner that is consistent as to thickness and three axis dimensions even if it were hand laid or infused— to say nothing of blown from a chopper gun. You will always have an imperfect fit between the irregular inner hull and the irregular “structural” liner. In addition because the part still undergoes the final stages of cure for days after removal from the mold, dimensions will always change somewhat . I’m thinking of a whole series of race car bodies I once saw abandoned at the Lotus Racing factory because they had warped after being removed from the mold .

    2- The most effective bonding agents like Plexus achieve their tenacious bond by being somewhat flexible. Therefore when they are part of a sandwich that is asked to carry high compression loadings the actual ability of the bolts to transfer load is both reduced and unpredictable compared to a solid laminate.

    My opinion— bolting a keel through a hull-to-liner sandwich is always a bad practice, no matter how many cost accountants and classification societies sign off on it.

    • John Jun 27, 2015, 7:25 am

      Hi Richard,

      Great information from one who has the practical hands-on experience to really know about how this stuff happens in the real world. Thanks so much.

  • Rumen Jun 26, 2015, 7:19 pm

    Thank you John for the good article. In my opinion, it reflects logic and common sense. You don’t have to be an engineer to come to the conclusion that the keel must always be attached to the hull no matter how hard the use and abuse is. It is beyond doubt that slamming upwind should not count as a cause for keel detachment. Groundings, even hard ones may cause damage but not to the extent that the keel falls of several months later without hitting anything. I cannot accept that the fault for Cheeki Raffiki tragedy lies in previous groundings, though this may be the cause. Many mass production boatbuilders incorporate a steel frame in the bottom part of the hull to which the keel is bolted. Is this that expensive?

  • Dick Stevenson Jun 27, 2015, 3:31 am

    Hi John,
    As a way of generating reasonable change in building practices, I would like to point out one part of our maritime world that stands in the way. This was a tragedy that could have been foreseen.
    A couple of decades ago, I had occasion to watch 2 boats over a couple of weeks being hauled into our local boatyard after finding our local rock with their keel while traveling at cruising speed. Both were of a similar type to Cheeki Rafiki and both were being considered total losses as the repairs exceeded their worth.
    I was appalled that relatively new, well known boats could be brought down by such a predictable event and wrote a letter to the editor of the various maritime magazines I read at the time. Not one, to my knowledge, ever saw publication. I have seen this repeatedly in our community’s publications: a shying away or ignoring subjects that might ruffle feathers.
    There are, of course, many avenues to building a groundswell of change, but, to my mind, our publications could be a leader in this area of developing seaworthy boats and attitudes. To that end, they are largely dropping the ball. This tragedy was predictable and inevitable.
    Dick Stevenson, s/v Alchemy

    • John Jun 27, 2015, 7:53 am

      Hi Dick,

      Great comment, as always. Your experience with those two boats seems, at least to me, to indicate that “Cheeki Rafike” should have been written off, if not after the first grounding, almost certainly after the second.

      Also, I share your disappointment in the lack of advocacy for change exhibited by the yachting magazines. My guess is that even 20 years ago many of them would have been up in arms with aggressive editorials calling for better hull to keel attachment. But today, all I have seen is carefully worded articles that simply rehash the findings of the report.

      I guess this reflects the reality that most of the magazines are being kept afloat (just) by advertising from the companies that make boats like “Cheeki Rafike” and the charter companies that buy them.

      • RDE Jun 27, 2015, 11:00 am

        The likelyhood that a magazine owned by a publishing conglomerate will act as anything other than a mouthpiece for its advertisers is about the same as the probability that a politician can open his/her mouth without lying. LOL

        I never cease to be amazed at how some people who have fallen into the gig of writing new boat “test” articles can look at themselves in the mirror. If they had spent all their careers behind the editor’s desk in Manhattan it might be understandable, but the individuals I’m thinking about have tens of thousands of delivery miles and circumnavigations under their keels. I guess they are just following the Golden Rule as explained to me by the corporate lawyer in one of my past ventures: He Who Has The Gold Rules.

  • Frans Jun 27, 2015, 11:53 am

    Hi John,
    Thank you very much for writing this!
    I think this is really the missing piece, and it solved for me the subliminal unease I felt after reading about the whole affair.

  • Marc Dacey Jun 28, 2015, 2:49 pm

    John, this is an excellent and forthright piece. If debate between the cadre of structural engineers and N.A.s who are actually responsible for production boat design and the bean-counters who finance the construction is sparked, much good will have been done.

    It does strike me, however, even as a non-engineer, that skinny, bladelike keels bolted only to the bottom flange of a grid could seem problematic to any small child who has encountered a see-saw with a fatter kid at the other end. The forces can be substantial!

    I also recall about a dozen years back taking a close look at a new Dufour 40, at the time a reputable and “to code” builder. I found to me what seemed to be deficiencies in construction, issues with tabbling and layup and many other “shortcuts”. The salesperson assured me that this model was “rated Lloyd’s Ocean Class A” to which I replied “I guess the sea will have the final word on that.”

    I have since gleaned the Lloyd’s specifications and the Recreational Craft Directive (RCD) in Europe in an attempt to understand *why* the standards exist…and where they might not be the best guide to what makes a small, seaworthy sailing vessel. I have concluded that the emphasis is largely on commercial vessels and that “certification” of a pleasure craft is not what it could be, leaving us disinclined to look at most newer production boats as candidates for offshore cruising. I found an interesting discussion of the “acronym argument” in this brief article on the Nordhavn trawler site:

  • Scott Fraser Jun 28, 2015, 6:46 pm

    Thank you for alerting us to the MAIB report. Your post and the comments above are very worthwhile.

    I alerted readers of SailNet to this thread and have made a long post there of my “takeaways”, which I will not repeat here. For those interested, its post #52 at…
    (Note that I blog there as “Billy Ruff’n).

    Earlier posts have pointed to differences between ocean racers and offshore passage makers in design, construction and profiles of use, but have failed to note what I believe to be an important difference that is relevant to this discussion. Specifically, it is rarely the case that you find a tired, worn-out cruising boat in an ocean racing fleet, but the opposite occurs with some regularity. Tired, worn-out (and potentially structurally impaired) ocean racers quite often become the inexpensive means by which a novice sailor strikes out on the adventure of a life time.

    Given the challenges faced in even identifying, let alone properly repairing, damaged boats build with hull -matrix designs, the recycling of retired ocean race boats into ocean passage makers seems like an accident waiting for a place to happen.

    • John Jun 29, 2015, 7:48 am

      Hi Scott,

      Good point on the dangers of repurposing a racing boat that has seen a hard life.

      However, I would class that as a symptom of the problem, not a root cause.

      To me we need to improve the keel to hull strength as specified in the codes for all offshore boats, regardless of whether they will be used for racing or cruising.

      In fact innovative steps have already been taken in parts of the racing community. The best example being the decision of the Open 60 class to mandate a massively strong one design keel for all new builds.

      And that in turn speaks to the fact that I am in no way advocating returning to the keel profiles of yesteryear. The fact is (as I say in the post) that even a modern keel with a narrow and short root can be made strong enough to stand up to the groundings and cycle loading that “Cheeki Rafiki” experienced, if we have the will and the classing regulations are upgraded to require it.

      In summary, I don’t think that splitting the debate between racing boats and cruising boats is a good idea. This is a problem for all offshore boats and should be addressed as such.

      • Marc Dacey Jun 30, 2015, 2:07 pm

        The sea is remarkably fair in the sense that it cares not whether you are in a racer or a cruiser upon its face. It will attempt to break up your boat and kill you in either case!

  • David e Bell Jul 1, 2015, 9:47 am

    I was just looking at the pictures of the Vestas Wind grounding for another writing project I am working on. The forces that the keel in that boat must have been extraordinary, and it stayed attached (and yes the whole boat was rebuilt afterwards). The point is that you can build these mechanisms so that they are strong enough, and still go fast.

    What is currently lacking is the will to build boats that are fast, stylish, affordable, and rugged. I do not envy the designers and the engineers, it is an uphill battle with their livelihoods on the line.

    What we can do is to help lead a way to a system where basic regulatory guidelines have deep foundation in fact and testing. I hope there are some younger and passionate people reading this, it is going to be a long haul.

    And then there is the question of the boats already in existence. At least with existing boats we can share what we know, and actively help those around us make good and wise decisions.

    • John Jul 1, 2015, 3:53 pm

      Hi David,

      Nicely said, I agree entirely.

  • RDE Jul 1, 2015, 12:01 pm

    Hi John & David,
    I think your argument that “modern” keel designs can and should be engineered to survive groundings misses the point about designing for the real world. Given an unlimited budget, brilliant engineering, and aerospace materials structures can be made incredibly strong. On need only to look at the modern F-1 or Indy car chassis that enables drivers to survive 80g impacts. Of course a Formula 1 team has 3-400 people all focused upon building two cars—–.

    There is a huge difference between Morgans Cloud’s keel or a swept back C & C design from that era and what is commonly known about hydrodynamics today. But that does not mean that a “modern” deep blade keel with a bulb would make Morgan’s Cloud a better boat! And increasing the mounting base area is still the most cost effective way of spreading loads and simplifying engineering.

    Even the Open 60 class has now mandated a standard “overbuilt” specification for the common canting keels. So why shouldn’t ordinary racer cruisers that receive ocean certification be required to sacrifice a fraction of percent of windward performance by meeting engineering and cost-friendly mounting base standards instead of just throwing more money at the problem?

    • John Jul 1, 2015, 4:07 pm

      Hi Richard,

      I completely agree that there are a lot of advantages to making keel root profiles larger.

      Having said that, I also believe that simple regulations are the best and most likely to be implemented and followed.

      Given that, my thinking is that we could fix this problem simply by upgrading ABS and ISO regulations to simply require that keel to hull joints must be engineered to withstand a hull-speed grounding with the impact on hard rock on the leading lowest point of the keel (most likely real world scenario) without structural damage. And further that said joint should be engineered to withstand a number of cycle loadings equivalent to those imposed by average waves over a given number of offshore miles, say 100,000.

      After that, let the engineers and builders figure it out. Believe me they will because their liability insurance companies will force them to once the regulations require it.

      As I understand it, this is actually the way that current ABS keel requirements work: specify a scenario that the structure must be able to meet.

      By the way, both Erik and Matt assure me that achieving the above is perfectly possible and even affordable, even with a narrow root keel. Having said that, of course you are right, the more extreme the keel, the more it will cost.

      I think this will be a much easier way to solve the issue than getting into mandating the size and shape of the keel to hull interface.

      • David e Bell Jul 2, 2015, 12:34 pm

        I think it is critical that any new rule, regulation, or specification on this subject be simple, straightforward, and clear. That is to say, in language and concepts that owner and the person actually doing the repair understands the goal, the methods, the constraints, and how to tell if the job (initial build or repair) is executed correctly and as the designer intended.

        Understanding will carry us a lot further than enforcement will. Culture is a powerful tool. Doing the right thing must be a matter of pride and not done from grudging respect for authority. Building strong is not enough. Waterborne structure has to be practically testable, and repairable. Anything less is asking for the water to be let in.

        Let’s get those engineers and designers out from between the rock and hard place so they can do what they love to do, create beautiful efficient sailing machines.

  • Chuck Hawley Jul 2, 2015, 8:29 pm

    I completely agree with your comments. The idea of bonding a grid structure inside a hull with some sort of adhesive (even 5200), and then being unable to verify the bond strength after normal use strikes me as being completely unworkable.
    I, too, lost a keel on a large sailboat, but luckily my fate was different than the crew of Cheeki Rafiki. The failure mode was completely different, however. The 10′ draft, 10,400# keel had nine keel bolts that were supposed to be welded to a fore-and-aft piece of SS plate inside the keel. However, the welds broke internally, so the bolts were able to slide out of the lead which surrounded them. The bolts, incidentally, were rod stock and not threaded stock, so the lacked any grip on the lead. Luckily, and for reasons that no one has adequately explained, we had enough stability to avoid capsize, even though we were sailing in about 15 knots of breeze.
    Anyway, thanks for the insightful analysis.
    Chuck Hawley

    • John Jul 3, 2015, 8:48 am

      Hi Chuck,

      Welcome to AAC and thank you for your valued endorsement of our concern about keel strength.

      Do you have any idea, based on your extensive safety ay sea experience, how concerned sailors can effectively lobby the classing authorities (ABS, ISO etc) to improve keel specifications?

      Finally, thanks for sharing your experience on a different keel fail mode. Scary stuff, glad it ended well.

      • Chuck Hawley Jul 3, 2015, 3:20 pm

        Hi John,

        My close friend, Stan Honey, is currently the chairman of the ISAF Oceanic and Offshore Committee, and he is pushing for more disclosure on keel failures on racing and cruising sailboats. I think ISAF has documented over 30 keel losses, some of which were on extreme boats like IACC sloops, while others were on production boats like this example and the Cape Fear 38. Incidentally, I thought the investigation into the Cynthia Woods keel failure was excellent. It helped me understand a ton about repair of fiberglass boats.
        An issue that Stan is fighting is the unwillingness to reveal the results of lawsuits due to gag orders. It would be dramatically more helpful to have the veil of secrecy lifted so that we could benefit from what’s discovered in these lawsuits.


        • John Jul 4, 2015, 10:08 am

          Hi Chuck,

          Based on your recommendation (thank you), I just did a preliminary read through of the Dobroth Report into the loss of “Cynthia Woods”.

          First off I have to admit that most of the math was way beyond my pay grade, but the key take away, at least for me, was that the boat was simply not built to ABS rules, or even close.

          This is very different to the case of “Cheekie Rafike”, a boat that complied with said ABS rules, but failed anyway.

          Having said that, like you, I learned a great deal from Dobroth, the most important take away, at least for me, was his assertion that groundings happen and boats must be built so that the hull to keel joint survives said event.

          He also intimates in several places that the ABS safety factor of 2 is inadequate and that many, perhaps most, designers double said ABS safety factor yet again. This would seem to support my thinking that we need to lobby ABS and ISO to upgrade their construction rules as they relate to the keel to hull joint.

          Obviously such a change would not have saved the man who died on “Cynthia Woods”, since the builders chose to ignore ABS, but it might easily have saved the four lives lost on “Cheekie Rafike” had the rule change been made before she was built.

          One final thought, reading Dobroth reinforced my thinking that we need to ban glued in structural liners (matrix) as a method to reinforce the keel to hull interface. While I’m sure it is possible to make said liner strong enough at launch, the inherent problems in quality and damage assessment, as well as repair, make this a poor way to build a boat.

  • Neil McCubbin Jul 4, 2015, 6:47 am

    Good article and follow up discussion.
    One cannot fault Benneteau for building to code. They are in a competitive market and any major expense beyond code would kill sales. It is not a matter of Benneteau profits, but of them surviving.
    Since a boat built to codes failed, and others have too, it seems that the code is inadequate, and should be changed.
    Defining keel dimensions is tricky, and will tend to block innovation. However, it would be possible to define minimum sideways and fore-and-aft loads the keel must sustain, including the appropriate allowance for fatigue, all appropriate to size and displacement of boat of course.
    I am an engineer, but not expert in boat design. That said, I find it hard to see how a substantial improvement in keel attachment strength would be very expensive. John’s 1% of boat price seem reasonable.
    To make this happen, and upgrade in code will be necessary, given commercial reality.

    • John Jul 4, 2015, 9:13 am

      Hi Neil,

      Thanks, good to have confirmation from another engineer (as well as Matt and Eric) of my thesis.

  • Neil McCubbin Jul 4, 2015, 7:36 am

    I just read the annex to the report.
    Seems to me that the report body missed some key points.
    – Although the keel bolts comply with the standard of the times, the did so only by a TINY margin. The analysis considered the possibly that the visibly corroded keel bolt was weakened. In this case, the bolts were non-compliant.
    – The backing plate for the nuts on the keel bolts did comply with a qualitative statement in the ABS standard that it be “substantial” but was below the ISO standard.
    The vessel was designed for use within 60 miles of safe haven, not for open ocean.
    In summary, the vessel was too flimsy for the open Atlantic

    • John Jul 4, 2015, 9:12 am

      Hi Neil,

      While you are right about the keel bolt issues, as the report says, these differences were trivial when analyzing what happened and are don’t materially change the fact that the ABS and ISO keel specs are totally inadequate.

      On the 60 miles from land issue, you are confusing (as many have) commercial class 2 which relates to gear carried, inspections, and crew training, with construction specification.

      As the report says, and as I quote in my article above, the boat was classified Design Category A, construction wise, by both the EU and British authorities as suitable for ocean crossings. That’s what makes the situation so distressing. While you are right that events show that “the vessel was too flimsy for the open Atlantc” the crew had every right to believe that the boat would not kill them in a force 7 near-gale at sea.

      I quote, once again, from the report:

      ISO 12215-9 defines Design Category A as: ‘category of craft considered suitable to operate in seas with significant wave heights above 4m and wind speeds in excess of Beaufort Force 8, but excluding abnormal conditions such as hurricanes.
      With reference to the hindcast weather data for 0300 on 16 May 2014, it is concluded that Cheeki Rafiki was operating within its design category criteria at the time of its loss.

  • Ed Finn Nov 3, 2015, 7:52 pm

    I just re read the article above on the loss of the Cheeki Rafiki, including the official report discussing backing plate sizes, past groundings and repairs,
    the rating of the boat,etc.
    I just took another look at the photographs above. Specifically, look at that photo showing a typical Beneteau 40.7 similar to Cheeki Rafiki showing the floor, hull ribs, keel bolts, and specifically the backing plates. I note the size of the backing plates .
    Then compare that arrangement to that original photo of the upturned hull of the wrecked Cheeki Rafiki taken at sea.
    Funny thing, I noticed that the steel backing plates are much larger then the corresponding holes in the wrecked fibreglass hull.
    At least three of the holes are much much smaller then the backing plates. So how could these plates pass thru the hull when the keel detached without enlarging the holes? How did they ‘pull thru’?
    Am I missing something here? Is it possible that the backing plates were missing … either since construction, or removed during a repair.

    • John Nov 4, 2015, 9:14 am

      Hi Ed,

      Hum, interesting. Having said that, I really don’t know, but it would seem to me unlikely that the investigators would miss such a thing.

      Anyway, even if they did, in view of the number of boats with keel attachments of this type that have had problems, that would not alter my fundamental point in the above post: the classification societies need to increase keel to hull joint specifications.

  • Roger Harris Dec 15, 2015, 10:18 am
    • John Dec 16, 2015, 10:34 am

      Hi Roger,

      Yes, I took a good look at that. From what I can see the failure is the same modality as “Cheeki Rafiki” and the Swan I discuss above. Bottom line, a keel needs to be bolted through structural members, not just the skin.

  • Drew Frye Dec 15, 2015, 11:28 am

    I’m late on the thread, but…

    1. Yes, advertising pressure is terrible. I write for several mags and I will not report on anything the advertisers sell. It is unethical. New boat reviews are obvious infomercials. I have been threatened with law suits 5 times (the most resent just a few weeks ago) for writing negative things supported by testing. It seems there are companies that would rather repel bad press through legal defense than R&D for better products. It tends to be the same companies over and over.

    2. The problem with “rot away” wood structures is not the loss in wood strength. I’ve design equipment that way, and so long as you take no credit for the wood it is fine. However, you must allow for the wood to expand when wet and freeze in the winter. Thus, the bilge is a terrible place for this design method. Have we not all seen split rudders? I wonder if Cheeki Rafiki had frost damage?

    3. Backing plates. I’m doing some studies on backing plates, breaking different materials against cored hulls. What has become clear is that when a large backing plate is needed, additional laminate is always better. With a plate, if the laminate fails at the edge, there is a zipper failure. Thus, if a 1/2″ SS 12″ square backer is called for, an additional 1/2″ of laminate over a 18″ square area with a 4″ backer is a MUCH better answer (the extra laminate is a 1/2″ backer that is bonded and will not zipper). A little more labor and curing time, but less weight and material cost. Anytime you see a large backer, view it as a short cut.

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