34th America's Cup: multihulls!

Patching a beam that was cracking in a test and then using it is a pretty big manufacturing no-no in composites if that is what was done. It wouldn't surprise me to see some lawyers sounding out that one. Sailors know that risk is involved but the building shouldn't take short cuts when the data says something is already wrong. Bean counters and safety aren't a great combination when big forces and high speeds are involved....The teams should be able to look everyone in the eye at the end of the day and tell them they didn't short change the crews. I'd rather see a one boat effort that was solid if slower versus a 2 boat campaign with fragile stuff sailed for the crash test. You have to finish to win.

 

Team Origin's Sir Keith Mills comments:

 

In the mid 1980's Nigel Irens designed the then fastest/longest racing catamaran - Formula Tag - the first boat to sail 500 miles in 24 hours. It was built by the Canadian airplane makers

When he introduced them to the project they said "great! we'll go and get a university involved, do some tests, make some mock ups..." Nigel said. "No you won't, the race starts in 6 months and you start building on Monday"

There are two things I learnt from my ISO work. The first is how long everything takes. First to get an agreed standard and second to get it into the public domain. Our work as a committee on the revised stability standard finished maybe 3 years ago. I think the standard is still not available to boatbuilders. The second thing is how much politics is involved even in something apparently uncontentious like boat stability

So I doubt if a standard can be written, the goalposts keep moving

The Achilles heel of monohulls is their keels and attachment to the hull. The equivalent in multihulls is their beams and attachments. In both cases nothing must ever break

So the simplest solution would be to take a leaf from the Vendee book. I believe these boats now use a one design keel and attachment even though everything else is still open

So next time (if there is a next time) the crossbeams should be one design and over strong and fail safe. A level playing field, cheaper and 100% reliable

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Never having posted here before, please let me express my great sympathy for Andrew Simpson's family. The pictures of him with his beautiful little children are heartbreaking to look at in light of this terrible accident.


As Richard Woods said immediately above, the beams and beam attachments can never be allowed to fail. Any remote possibility of it has to be re-engineered, to be completely out of the question.

I don't recall ever hearing before, of such a total beam failure on a large racing multihull. Daggerboards may break, rudders may snap, rigs can fall down, but a main beam coming apart like that in a nosedive is completely nightmarish. Nothing in the way of safety measures/chase boats can be sufficient in that case. It leads me to wonder if the Artemis team was sailing the boat with the knowledge that they had to keep an eye on the beam for warning signs, but without appreciating the sort of violent failure as that which unfortunately occurred.

If it's true that the beam was damaged back in October because they had tow-tested it with pre-tensioning below but not above (!), then what options did they have under the AC34 rules to fix it? A complete replacement would I guess have been at odds with the rules.

Not having seen an accident like this before, it seems no-one was adequately aware of the danger it posed.

 

biplane rig

can't see how racing giant beachcats in San Francisco summer with a mastheight twice the length of the hulls is the optimal setup, whether in terms of pitchpoling or speed

two, lower rigs side by side = reduced forces for pitchpole; greatly reduced force at the midpoint of the crossbeams; and more sail area!

crossbow II, clifton flasher, charente maritime, jaz, techniques avancees, spitfire, hydraplaneur, fifty-fifty

biggest loss would be reduced height for the downwind headsails

 

Hi All - Everyone knew the dangers involved. They planned and trained for such an incident. Unfortunately such an incident can't have an absuletly known conclusion, if Andrew had been 1foot different in the boat he may have survived, or had done something 1 second different etc etc. An equipment failure killed an AC sailor in 1999 and we kept sailing. The designers, engineers, builders and sailors do not scrimp on the structure and certianly do not intentionally do anything "unsafe". The boat would have been load tested and deemed accetptable. It may have been its planned last day out before they built No2 etc etc. Being a composite engineer involved in 30 years of boats just becuase you have a "standard" or a high safety factor does not assure you of non failing equipment. This is very complicted stuff. Blackburn look up the Phillips boat for "The Race" RIP Andrew. Regards Peter S

 

The AC34 teams are well prepared for different capsize situations, where usually there is slightly more time to react. Team Philips (the main beam began to fracture in bad weather?) doesn't seem to be a good enough comparison.

I don't think it is true at all that anyone has trained for a situation where the boat comes apart as happened with Artemis, and I don't agree they 'knew the dangers involved'; instead I wonder if members of the Artemis team may be extremely upset about what happened over time to allow this accident to occur.

 

Team Phillips was a poor design concept, although it was the builders who got the blame. The bow fell off on almost its first sail and after repairs the boat was abandoned in the N Atlantic when the central cuddy started to break away from the hulls

But multihull crossbeams do break eg

http://www.youtube.com/watch?v=W2WiM2MHpQI

it's not speed per se that is a problem, rather it is lack of control at (any) speed that can kill.

Richard Woods

 

Artemis

I'm not sure we know the cause of the Artemis tragedy-and talking as if we do just goes nowhere.......

 

Groupama 3 is a better example, and it was a rapid failure, not gradual... do you know if they identified the reason for the 'shearing' of the beams/hull?

I'm sure there are more trimarans especially, which have had beam problems of one kind or another. When I think of it, Hervé Cleris when he was skipper for Prince de Bretagne (2009?) had a hull drop off of his new Nigel Irens design, and wasn't Yves Blevec making desperate patches on his main beam in his last Route du Rhum?

However, what I said was "I don't recall ever hearing before, of such a total beam failure on a large racing multihull", and in comparison with what just occurred with Artemis, I cannot think of an equivalent.

 

The video I was looking for was the trimaran breakup in the 2002 Route Du Rhum, but I didn't find it quickly. Lots of multihull crossbeams have broken over the years, even when they were designed to the predicted loads, and deciding what those are is the real crux of the problem.

I have only read some of the reports and seen some videos, but I think we know why Andrew Simpson died. He was trapped under a broken hull and crossbeam. Why the hull/crossbeam broke is another matter all together. If the beam hadn't broken he might have survived.

Richard Woods

 

There seems to be a lot of assuming as to the cause.

A main beam design problem is a possibility, not a certainty.

Rules for designing one off first of kind boats would be tough.

I am as concerned about manufacturing problems and post manufacturing damage as I am about a "bad design".

What about requirements to monitor strain gauges and then mandate regular static loads tests with a healthy factor (push strain gauges to 2x sailing readings?) to ensure any failure occurs on a test stand.

 

A Sailworld article quoting Nathan Outteridge's father Tony Outteridge who spoke to his son after the accident apparently the boat "folded like a taco" during a bear away. They had made the decision to abort the session due to the strengthening wind and were about to head back to base when the accident happened:

http://www.sail-world.com/Australia...tteridge---It-folded-like-a-taco-shell/109405

 

Having a failure occur during conditions increasing above what the skipper considered the "operating zone" may indeed mean the boat was exposed to the maximum loads it had ever seen.

I am certain they have lots of strain gauges being recorded during each run.

I hope that the recording device was designed to survive an accident (i. e. black box rugged).

 

If a guy is too deep for a snorkel and a air bottle won't last perhaps one of the chase boats could be equipped with a air hose to a compressor. Many of the commercial divers use this kind of rig around here to avoid having to switch tanks etc....