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http://coastguardnews.com/4-mariners-dog-rescued-after-boat-breaks-...

Sad new's, I wonder whats happened. Alot of talk around the aero rig to blame but few facts.

Thankfully everyone survived

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Wow! Wow!

I am speculating here, but this appears to be a highly modified Pahi 52 (CG report stated 53') with at least one main beam (#3) missing, which is only a available as a professionally built boat. And since the rights to build the Pahi 52 exclusively belonged to Gunther Nutt (Seascape) until recently, and there are pictures and discussions circulating about this boat from 2010, we can either speculate that Gunther built the boat, without approval from JWD for the changes, or the design was stolen and modified.

Some aspects of the flaws that I can see:

• Elimination of Beam #3, though by itself is not generally an issue since Wharram has been known to approve the removal of a single beam for several of his designs to accommodate builder's wishes. But when added to the other flaws, it probably spelled disaster.

• All beams appear to be modified from the original design.

• Though difficult to tell, there seems to be a mixture of flex design and monocoque for this boat. Beams 1,3, and 4 appear to be lashed, while the fore and aft tramp beams appear to be fixed. The center structure also has the appearance of having aspects of being fixed to the hulls/decks in various places.

• Unstayed Aero rig with low bury depth on the spar, which would exert too much pressure on the structure and beams.

• Massive center structure that covers the main beams. It would have to be heavily built to support the Aero rig, and all that weight was supported by 3 beams instead of 4.

• The overall changes in the design gives limited ability, if any, to inspect the beams, troughs, and/or inner lashings, which need to happen regularly.

This boat, with its high level of fit and finish, appears to have cost the original builders a considerable amount of money. I am just glad that it did not end up getting them killed.

What is the moral to the story? If you do not know what you are doing, stick to the design. If Gunther built this, he should have known better. If it is a stolen and modified design, they are lucky that the bad karma didn't get them killed.

The boat was conceived in Canada more than 20 years ago and launched in 2003. The hulls are very similar to the Pahi 42, but they said it was based on the catamarans of the native American Indians of the Pacific Northwest!

There is some info in

http://www.uksailmakers.com/NO-SLOW-DANCING-HERE_1_598.html

and a discussion with more pictures in

http://www.boatdesign.net/forums/multihulls/nootka-dancer-32513.html

Let's be careful here. First, there is no known evidence of NW native Americans ever building catamarans! In fact, I find the assertion absurd. The link you provided is authored by UK Sailmakers, whom are simply quoting John and Helen Eisner, whom at this point should be suspect?

Why? Because "Its unique profile...", along with most of the hull features, are astonishingly similar to a Wharram Pahi 42/52. Neither of the two links provide any real insight into the builders, or any useable facts that do not pertain to the rig. Suffice it to say that it was most likely NOT built by Gunther Nutt/Seascape. That being said, this boat appears to be a highly modified stolen JWD Pahi that suffered a catastrophic failure at sea.

Andrés said:

The boat was conceived in Canada more than 20 years ago and launched in 2003. The hulls are very similar to the Pahi 42, but they said it was based on the catamarans of the native American Indians of the Pacific Northwest!

There is some info in

http://www.uksailmakers.com/NO-SLOW-DANCING-HERE_1_598.html

and a discussion with more pictures in

http://www.boatdesign.net/forums/multihulls/nootka-dancer-32513.html

It was a stetched 42 from what I have heard.  Saw it once in an earlier iteration.

Seems to have been bought by some people called Nice?  Is that correct?

So far I have heard zero reliable anything on the actual failure mode.  I don't even know whether it failed longi or tangent.  While the modifications it initially suffered were crazy, that happens a lot one way or another.  Russ Brown's original proa broke up; Piver's boat killed him, maybe: Wharram's original cat, was very unworthy; An Early Gougeon tri broke up; The first Harry broke up;  Newick's Cheers capsized drastically;  and on and on.  It has been my experience that if you want to design something truly novel you have to be willing to make one, and possibly a second to get the bugs out.  But often the course correction is all it takes.  Often the difference between a designer and a client is just that willingness to make something that may not work, at first.

The current version is hugely modified from the original modification.  It could have failed due to rot, or something that does not necessarily have to do with the modification, though if it split in half, and sank, there was something seriously unusual going on.

If, as it appears, it has been around for a good many years then it is likely the cause of failure now is rot or some other material weakness. But the design does seem a very strange combination of monocoque and flex as mentioned before. Particularly I don't see how the stresses from the base of the mast are transfered out to the hulls - or rather, they can only go through the bridge deck construction which would presumably cause very high loads on the inner hull to beam areas. My friend's proa has an Areo rig, but that is very strongly bonded into the hull it stands in, both at its base (keel) and at deck height.

Well, per This link:  http://www.yachtingworld.com/news/three-crew-dog-rescued-us-coast-g...  provided by Chuck, it seems that this boat was in fact a modified Wharram.

This set of ridiculous modifications to an otherwise seaworthy vessel should not be allowed to reflect poorly on JWD.

And if "rot" was an issue, then that is because the design modifications contributed to the rot by concealing what is normally exposed, and not allowing for proper inspection and maintenance. Again, the removal of beam 3 from the design and addition of what is certainly significant weight of the central section and enormous torque upon the beam(s) and structure by the Aero rig certainly contributed to the failure.

I also found a link to a sale listing for the boat which states that the modifications were "approved." So I must wonder if ALL of the modifications were approved, or just some of them.

http://sacsmarine.com/wharram-custom-53-catamaran/

If your friend has a Harry Proa, one of the first owner built versions, a real beauty in construction quality, that seemed to have followed the plans, tore the mast loose at the mast foot, and they nearly didn't get to the end of their first crossing.  The boat was fixed and subsequently put up for sale.  The builder had missed a detail, a very important detail, I think he used a pair of ring bulkheads in that position, rather than a solid one.  The designer is a very experienced guy in proas, Aero Rigs, and carbon spars.  All I am saying is that even guys who do a great build in accordance with clean plans, can screw up. 

George Carlin has this famous bit where he imitates a driver who thinks anyone who drives faster than him is an idiot, and anyone who drives slower is a moron. The reality is that on average we are average, and we should be particularly cautious about the opportunities for goofing up that are presented to all of us.  The herd reaction is to assume the lions only get idiots, morons, or weaklings, when what they actually take are any targets of opportunity.

kley said:

If, as it appears, it has been around for a good many years then it is likely the cause of failure now is rot or some other material weakness. But the design does seem a very strange combination of monocoque and flex as mentioned before. Particularly I don't see how the stresses from the base of the mast are transfered out to the hulls - or rather, they can only go through the bridge deck construction which would presumably cause very high loads on the inner hull to beam areas. My friend's proa has an Areo rig, but that is very strongly bonded into the hull it stands in, both at its base (keel) and at deck height.

I would only believe that, which I had seen, from the JWD team.  The reality is almost everyone deviates from the plans, and almost none of it gets approved, so most people think of modified boats as stock.  But the degree of modifications here go beyond the normal range of modifications, as to materials and details that many make.  I don't really believe the JWD team has the engineering capacity to evaluate the load paths of an aero rig, though it isn't to hard to model.

Budget Boater said:

I also found a link to a sale listing for the boat which states that the modifications were "approved." So I must wonder if ALL of the modifications were approved, or just some of them.

http://sacsmarine.com/wharram-custom-53-catamaran/


Rot is common to the design, and I have just cassually read of several people who have had to replace their beams.  It is also a design issue as several of the design types deviate from best practices, where beam rot is concerned.  I think your questions are rational as to where to look, but even the presence of rot does not mean it was the cause of failure.  I have yet to hear categorically which way the boat folded, though the two hulls separating along the beams seems most logical.

A conspiracy of several factors could have harmed the boats chances:

Two wide

Twofold reduction in under deck clearance, due to using hulls that are too low as a result of the stretching process, and too widely set.

Large loading from removal of shrouds,

Large loading due to mast leverage.

If they got under the deck pounding in a seaway, the mast bending, the shrouds gone, and maybe some rot.  The beams could have gone.  Sinking is still an oddity.

But the failure could  have been something prosaic like a container.


Budget Boater said:


And if "rot" was an issue, then that is because the design modifications contributed to the rot by concealing what is normally exposed, and not allowing for proper inspection and maintenance. Again, the removal of beam 3 from the design and addition of what is certainly significant weight of the central section and enormous torque upon the beam(s) and structure by the Aero rig certainly contributed to the failure.

I read on another forum, that a person who was passingly familiar with the boat indicated that the beams had been constructed of steel. If true, then such weight would certainly overcome the neutral buoyancy of the hulls and sink her if the lashings or wooden structure failed.

We can also assume that the boat did not necessarily "sink," but was floating in a neutral manner similar to a jettisoned shipping container, and was simply reported as "sinking." We may never know all of the answers.

Tam Dl said:


  Sinking is still an oddity.

for this craft to be legitimately connected to Wharram it would first be worthwhile to hear what JWD has to say in agreement......if so at all.

It reminds me of another designer builder who called his catamaran a "Wharram off-shoot" and the comment from another knowledgeable Wharram owner that the "off-shoot" was shot so far off that it missed the target completely.

Even so, the "off-shoot" catamaran survived some fairly extensive cruising, while this creation has failed spectacularly not far from it's home.

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