Claudio - not sure that I agree with you about multihulls being dangerous.
A very good, and personal friend of mine (and his fiance) from Michigan, racing a monohull in the Chicago to Mackinaw Race on Lake Michigan died along with his girlfriend when they were caught in a storm, and the boat capsized pinning both under the water. Thus, one could also conclude that monohulls are also dangerous when a crew (or two) dies.
A multihull, when capsized provides a very stable platform either right-side up or bottoms-up for crew, however, with the lines, standing rigging, sail cloth and hardware, I think you must agree that becoming trapped and drowning is not the pure fault of a boat’s design - one hull, two hulls, or three.
Just my own personal view and opinion. Regards, Dick
Of course Dick, even in the 79’ at the Fastnet race only 28% of the monohulls crossed the line. I wonder what would happen with multihulls. Of course the extreme conditions do present risks as was also the case with the Sidney-Hobart.
In the actual accident, was no matter of stormy weather but rather a structural failure according to my understanding. Structural failures are more probable with multihulls IMHO.
I was reading on the Italian press that Bertelli is considering the hypothesis to withdraw from the AC Cup, actually he left the decision to the crew.
Cheers
ClaudioD
In the past we have seen V5 AC boats break in half and sink, masts crashing to the deck and heavy boat contact where fortunately no-one was seriously hurt.
Sailing in any form can be life threatening but AC 72’s are at the extreme end of the sailing now with high speeds foiling and wings that are not forgiving if you’re caught in the bad situations such as high wind, rough water, tide ebb etc. …
AC 72’s are at the knife edge of development and proven to be fragile with serious two incidents where the boats have completely disintegrated when something went wrong… the recovery rate of the boat is NIL ! and IMO should be seriously considered if there should be any attempt aloud to rebuild a structural compromised boat at all !!! as the risk of structural failure must be considerable higher.
Bravo Mr. Bettelli !! let the experienced decide for themselves …the sailors !!!
So, a question … at what size should a multihull be considered “Extreme”?
We have the 72 footers now preparing for the AC Cup.
Conner’s cat (with wing) was about 64 feet if I recall correctly (?)
We have 60 foot Round The World (ORMA) boats (both two and three hull)
We have the 45 foot “Training” boats for the AC competition.
We have Formula 40’s that raced in the late 1980’s (both two and three hulls)
We have 30 footer catamarans (with wing sails) that race for the Little America’s Cup ( C Class)
We have 27 foot cats for day racing
We have 21 foot cats for long distance offshore and Round Island racing
We have Formula 18 cats for day and long distance racing
We have 18 foot closed close single handed cats for day racing
We have 18 foot, 16 foot and 15 foot cats for day racing
The Hobie 14 is probably the cat that started the multihull “Craze” back in the 1970’s
All of these at one time or another “could have been” considered the extreme end of sailing - but before we leave let’s not overlook the big cat that really remains the “grandpa” of off-shore racing - the 125 foot long“PlayStation” that had done several ocean crossings, and I would suggest the 72 footers might be cutting edge but until tomorrow when someone comes along with a 75 - 100 footer, I can’t say I would call the boats today as “Extreme”. Seems too early to suggest that title should be bestowed upon the current crop of racing multihulls.
Dick,
one element that is new in AC multihull is the rigid sail, all other multi use soft sails that can be reduced as function of need.
Now if the Rigid Wing would be reduced in height, probably the sailing will more safe and all being the same the problem is solved.
Less sail surface area = less stresses on materials = safer "extreme"conditions
Sorry Claudio -
the AC 45 foot “training” boats, the C-Class 30 foot cats, and even the 17 foot A-Class cats all use rigid sails of some specific size. None of these listed have (to my knowledge) any easy method for reducing sail area depending on wind strength. They “sail what they brought” and the knowledge and experience of the skipper (or trimmer on larger boats) are responsible for trimming the sails and adjusting for wind strengths and direction. If Artemis “folded” due to improper engineering is one thing, and can’t be blamed on the boat. Like any structural failure, if engineered or built to improperly sized scantlings, I liken it to a variety of racing - keep building it lighter until it breaks, then back up one step in construction to help with longevity. I would assume this is true in monohulls, in automotive racing worlds, off-shore power boats, etc. Didn’t one of the IACC design boats “push” it’s mast through the hull and sink (or nearly so) in San Diego? Haven’t we seen photos of our R/C sized craft that have been dismasted because of shroud or backstay issues? Certainly they wouldn’t be considered extreme.
I think Claudio has right. It’s not LOA, it’s the relationship between the thrust of the wingsail, the LOA, and the curve of areas of those hulls that make these boats extreme – too extreme, IMHO, for SF Bay, where I grew up. The “zone of death” problem with some cats (risk of pitchpoling when bearing away) is compounded once by the area of the wingsail and again by the inability to depower. Add the “glass bottle” failure mode of carbon fiber and you get one scary beast. Best evidence so far is that the boat dug in short of a full pitchpole, overstressed, and disintegrated.
Hi Dick,
this is exactly my critics about rigid sail.
Probably the elementary Naval Architecture safety criteria are simply ignored and the Rules definition could be the major responsible for the catastrophic accidents.
Marchaj wrote a full book the “Seaworthiness the forgotten factor” where he is highly criticizing the IOR Rules. Fastnet story is widely discussed.
It is not sufficient to draw a Hull, put any Mast on top and decide what will be the Sail Area.
Too many structural failures occurs on mono and multi, proving the numerous design deficiencies ! this is a luxe that only modelers can afford !
ClaudioD
It’s not that every rigid sail is a problem, it’s that an excessively large rigid sail produces too much power coming on too suddenly during the reach portion of the bearaway and generates a shock load on the structure.
based on that, lets ban sailing for the America’s Cup…since sailing caused his death…
I don’t think foiling caused the accident. I think a poor design is what caused the accident or more likely sailing a boat beyond its design characteristics. IE foiling on a boat that was not designed for foiling. IE slap in some dagger boards with foils and see what happens, then yes in a sense foiling did cause the accident.
My point was that all of the aforementioned boats at one time or another were considered “extreme” by many (most) of the sailing community - only to find favor (and sales) by those with interest and spending ability. Earl - As for depowering - the most obvious is to allow the wing to have 0 degrees of attack angle. If there is no lift on either side of the wing, and the wing rotates so it points into wind, sufficient depowering can be achieved. One problem is a solid wing does not behave like a softsail tethered to a rigid mast. In a sense is it one large rotating mast. Without shrouds, it probably could sail backwards. Add in the ability of a hard wing to shed power by use of various “flaps” to control camber and to create it’s own apparent wind - and one doesn’t sail a multihull like a monoihull. One major issue is that the crew of a multihull replaces the monohull’s lead keel, and in most cases crew weight is less than what would be ordinary for a monohull with similar sail area. Earl - since I haven’t seen much of detailed photos, and loss of mast/wing suppoort of the maincross beam (dolphin striker or similar) could also have caused a similar result - which again, is also possible with a metal mast and a soft sail multihull. Give all of our thoughts and ideas, it is to be noted that this is not the first case of structural failure on that particular boat leading up to this one. Dropped wings from broken shrouds (or ripped from capsize) is one thing, but total destruction of a solid platform is a completely different issue the team must look at a evaluate. San Fran Bay has proven “extreme” for a variety of boats, classes and events. I think the event producers were looking for maximum exposure and high winds for good public viewing. Perhaps like racing a large r/c monohull in the “Gorge” on a particular windy day.
I understand there is a competitors meeting in SF today, we can only wait to hear how they propose to move forward, however, with less than 2 months before the start of the LV to start moving the goal posts now is going cause some controversies.
Reflecting on the technology being used and resulting speeds now being reached by these boats together with the inherent risks attached and the fact that none of these boats have raced together on a “tight course” yet … there is still a lot more learning still to take place.
Is this AC going to be close and exciting racing ? using the WS 45’s as proof of concept, it’s a failure already as AC match racing is clearly not suited to these boats and with the postage stamp size course restrictions & boat these speeds that will be applied to AC 72’s for “new” safety reasons … the yawn factor will be x 72.
Maybe the solution could be to make this AC a “Speed Run” event, forget sailing fleet & match racing (not suited to AC 72’s anyway) and just make it pure drag race ! and let’s get this multi diversion out of the way and then we can get back to real AC sailing again !!!
Match racing the 45s would be safer than the 72’s and at the very least they have proven their mettle/durability on the course. Plus the larger number of competitors would be one way to save face and really keep this an exciting event. more boats=more fun
of course they can always fleet race and loose the match racing. The fleet racing has proven to bee fun to watch, when the starting line was long enough and the course laid out properly to allow to enough space for mark rounding…
the first Cup races were fleet races…we could get back to our roots…
The question is not whether wing sails can be depowered in general. The question is whether a 131 foot tall, high efficiency wing sail can be depowered rapidly and sufficiently to permit a safe bearaway turn. Even at a zero AOA that thing is going to generate significant lift and the implications of that can be understood by looking at the postings in this thread:
Even if one avoids a pitchpole the maneuver generates shock loads on the structure, and composites don’t like shock loads, especially repetitive shock loads at the same stress points. The possibility of a progressive failure over time is a real one.
All this points out that these beasts may not be everybody’s idea of “extreme” but they are certainly experimental. Nobody really knows much about them except what the computer simulations tell them, and many of us have been down that road before. San Francisco Bay is a wholly unsuitable location in which to test experimental craft capable of 40kt or greater speeds. I spent many a happy hour powerboating there as a Sea Scout and I can tell you it is a place whose great beauty hides many dangers. The water is cold, the weather is capricious, it is crowded, and being essentially a giant river mouth it generates ferocious tidal currents, as the Oracle team learned when the wreckage of their boat headed smartly out to sea and was captured only at the last moment. The teams are required by their agreements to race in conditions (up to 30kt wind, no factoring for sea state) that has experienced Bay sailors shaking their heads – all this to avoid inconveniencing the television coverage by having races cancelled.
Now the question is, what are the organizers going to do about it? The idea of a B rig was dropped for cost reasons and there probably isn’t time and money to cut down the present rigs. Ditto for making the boats stronger. The only options I see are to jeopardize the TV coverage and tighten up the sailing limits and go to a “racetrack” course which eliminates the need for bearaway turns at windward marks. The risk of collision, running out of real estate if there are control problems, and catapulting crew members into the air in the event of a pitchpole remain. Too big, too fast, and too little time to learn.
“The Artemis team has yet to indicate its clear intention to continue with its challenge. The boat which broke up cannot be sailed and will need time to repair, a process which may be hampered if reports that its second boat, the one it intended to campaign, suffered some damage in transit from Sweden” Reported by [u]Independent[/u]
Hope their misfortunes turn the corner for the better soon !
