10 mill$ poweryacht capsize during launch in Anacortes

Rasputin22

Rasputin22

Rasputin22
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The FUNKYFORM ™ FLIPPER 85. Has a nice ring to it.

On the stretching topic, such mid body additions are more common than one might think in powerboats. I'm presently doing a 3d model of a 220' 'donor' hull which is getting a 26' mid body plug with an additional 6' of false bow planted on for a better looking profile. A whole extra top deck is being added as well so the top hamper is increasing. Glad I don't have to sign off on stability but the donor vessel is a Gulf 'Mud Boat' with massive tanks which will have a few hundred tons of concrete poured into them after re-launch.

Here is a the first stretch job that I modeled from GHS files a couple of years ago. This boat had served its role in the Gulf of Mexico servicing the offshore oil rigs and was in the Alaska King Crab fleet. Talk about needing stability. The eventual owner and his skipper were watching 'Deadliest Catch' and he was so impressed at the pounding it was taking on the show with crab traps stacked 30' high that he bought it at the end of that season and has done 3 refits to it. Carries all his toys in a big hangar and it is the 'Shadow Yacht'to his fine Dutch built yacht. They cruise in tandem and the toy hauler can carry more than enough fuel for both of them for just about any passage. These boats are actually so stable that they have what is known as a 'flume tank' that sits up relatively high in the superstructure that us filled with ballast water to slow down the snappy roll that they get when the mud tanks get pumped dry.

https://player.vimeo.com/video/64958395
 
Jose Carumba

Jose Carumba

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You're lucky to be working with a boat that (I think) pretty much has a parallel mid body Rasp. Easy to stretch. When we stretch our molds production wants a direct transverse cut while cutting along the curve formed by points of tangent would work better. Of course if there is any drag angle to the keel it gets a bit more complex and the sheer line in the aft portion of the hull needs to be raised. On our latest 130 mold I created a transverse cut line with true tangent all the way around, as if creating a parallel mid body vessel without the mid body. Now to lengthen the hull we just need to pull the ends apart and fill in the gap. Easy peasy, sort of.

 
Rasputin22

Rasputin22

Rasputin22
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Cheoy Lee insisted I butcher a really sweet Witholtz double ended trawler design in much the same manner. The original design was based on your PNW gillnetters and they used to build it as a 68'. I tried to pick the tangent points much as you describe and the resulting cut was skewed from vertical. I think they opened it up to 80' feet. Such a shame and I'm sure Charles was rolling over in his grave.

Wittholz66LRMY.jpg
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Just looked at the Cheoy Lee page and it was actually a stretch from 68' to 83'! Turned out that their mold was so distorted and assymetrical that it was worth doing the stretch. I begged for and finally got them to do a laser scan of the mold and send me and when I modeled a a surface model from the laser point cloud and mirrored one side to the other we were all shocked at how out of whack it was. They did have me do a swim platform/ planing trim tab extension on the canoe stern and they built a few at 68'. That platform looked like the tail of a platypus but did keep the boat from squatting at speed and was functional. What they did to the traditional superstructure from some Australian auto industrial designer was a travesty. Tried to put the 'Italian Sunglasses' look on a traditional double ender design, I still cry thinking about it...

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M

Mudsailor

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I'm going to try and explain the owners comments.....best guess.....

Dolly collapses on one side, boat is not afloat, stern is still going down (has not gained enough buoyancy to float or provide any stability yet). stabilizer fin hits launch ramp and stops the boat from falling over. Note: vessel would be stable if upright, but now with this heel angle allowed by the dolly the boat is now past it's angle of vanishing stability for this displacement and launching position, they keep on launching....hoping that as the vessel starts to float it will be OK....but the boat will never recover, as it finally starts to float it cannot gain enough form stability to right itself and capsizes.

Note.....not associated with Northern, still think they massively screwed up, and yes, I'm a Naval Architect

 
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Jose Carumba

Jose Carumba

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That's a reasonable explanation, but Brings up the question of why the boat, reportedly, tried to roll when the slings were released. Perhaps the movement of the slings imparted some motion to the boat and the operators were skittish about letting it move too much.(?)

 
G

Great White

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Jose Carumba said:
That's a reasonable explanation, but Brings up the question of why the boat, reportedly, tried to roll when the slings were released. Perhaps the movement of the slings imparted some motion to the boat and the operators were skittish about letting it move too much.(?)
Click to expand...
I have wondered about how much machinery and equipment came adrift and ended up on the port side. That could possibly cause a port list when the slings where loosened.

 
M

Mudsailor

Anarchist
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So Cal
Jose Carumba said:
That's a reasonable explanation, but Brings up the question of why the boat, reportedly, tried to roll when the slings were released. Perhaps the movement of the slings imparted some motion to the boat and the operators were skittish about letting it move too much.(?)
Click to expand...
Agreed, I can't figure that out. I could see some interior furniture etc moving, but not machinery, maybe the ballast shifted when it rolled?

 
Pertinacious Tom

Pertinacious Tom

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Ever pick up a thoroughly soaked seat cushion? They're surprisingly heavy. Maybe that whole side of the boat was soaked enough to make it want to list when the slings were released?

 
SemiSalt

SemiSalt

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Jose Carumba said:
That's a reasonable explanation, but Brings up the question of why the boat, reportedly, tried to roll when the slings were released. Perhaps the movement of the slings imparted some motion to the boat and the operators were skittish about letting it move too much.(?)
Click to expand...
I didn't see any report about this "roll when the slings were released" that wasn't pretty far along the grape vine. Pending a first person report, I don't take it too seriously. I can definitely see that the operator would have "take no chances" mentality, especially if he was exposed to the sort of speculation about complete incompetence that was reflected at the top of this thread.

 
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