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Old 01-08-2005, 04:36   #16
Kai Nui
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Since it appears that you do know the math, how many cubic ft of air would it take to right a 9000, or say, 10000# tri with 20' beam, 35' LOA, 40' mast, and woud it be more likely to come up on the beam, or stern first? Additionally, as you seem to be knowlegeable on such things, can you tell me, if she comes up on the beam, will the downside ama submerge, or is there sufficient bouyancy that the weight of the vessel (1000#) can be floated on this single ama.
While you are at it, will surface tension affect the equation substantially? I know a certain degree of suction will be created, but how will it be calculated, considering the shaped surfaces of the deck?
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Old 01-08-2005, 09:41   #17
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I know enough maths to know that the buoyancy required to right the boat is too heavy for me to winch down the the "top" of the mast (always supposing I could keep my breath for long enough to operate the winches!)

I know that wood (cat designer) experimented with controlled flooding (either at the bow or stern cant remember which) on one of his designs that brought the boat to such an angle that a wave would bring it back upright. I believe that this worked, but have not heard anymore about it so obviously wasnt very popular.

IMHO it is more important to concentrate on how to avoid getting upside down in the first place, and a series drogue is a good start.
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Old 21-08-2005, 04:37   #18
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Turtle Rescue

This trimaran from Gemini/Telstar has amas that can be fully retracted while in the water (pull in, not fold down like the standard trailerable tri's). Its not designed as a turtle rescue feature but it might help a lot.
http://www.geminicatamarans.com/Performance_Telstar.htm
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Old 22-08-2005, 04:33   #19
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Modern hi-tech is great if you can afford it. Unfortunately, my budget does not fit the Geminis. Hi flow electric transfer pumps to flood and pump the ama is a common install on tris around here; at least older ones, but as no one I know has turtled, the effectiveness of any of these ideas seems to be purely speculation. This brings me to my earlier point; turtling is just not that common of an occurance.
Just out of curiosity, does the gemini use the retracting amas in other than full out positions? Sort of a trim feature?
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Old 23-08-2005, 05:53   #20
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Its supposed to be a trim feature I think, to help with scooting round marinas and berthing in monohull spots.
From some online articles it sounds like motoring with the outboard is normally done with the amas in too.
Tiller shackles to the outboard for manouevreability too.
I wish I had $62000
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Old 23-08-2005, 06:35   #21
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Pocket change, right?
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Old 24-08-2005, 01:50   #22
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Having sailed both monohulls and multihulls, I see the advantages in both designs. I think it really depends on the kind of cruising you are planning and your budget.

Although I haven't experienced extreme conditions in either design, my gut feeling is that there are extreme seastates that would make me very uncomfortable in a multihull and slightly less so in a mono.

BUT, for the kind of cruising most of us are used to (for me the tropics of the Gulf of Thailand), I think a big, ugly, expensive multihull would be the way to go.

Now, if only I had a lot of money and could settle for ugly.
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Old 24-08-2005, 02:15   #23
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I would always prefer to avoid the rough weather, but it happens. As for safe... an old wooden double ender anyday, but as for comfort, a multihull appears to be the way to go. Afterall, the amount of time spent in places where a multihull really shines (including anchorages), is by far the majority of time spent cruising.
Now, as for ugly; You may not see the beauty in a sleek aerodynamic design skimming across the water at 15 kts, but that, to me is every bit as pleasant as an old cutter rail down running full and by. Of course if you are one of those who spends hundreds of hours each year making sure your bright work is perfect, plywood and lexan probably don't get it for ya.
Oh well... Different strokes.
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Old 25-08-2005, 20:56   #24
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I know it's not supposed to be a mono vs multi forum here - but I've recently been recommended (elswhere in these fora) to look at a cat for planned upcoming trip into the pacific - Australia being the goal. I'm having a hard time working out whether a cat is a safe alternative. It certainly seems to be an expensive one (since new (or at least newer) seems to be the recommendation - but shows advantages for my wife (anti-leaner and seeking better accomodations).
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Old 25-08-2005, 21:23   #25
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I will be making a similar trip (just a bit longer) to Australia in a few years, and I will be doing that in a Cat - probably a Prout Snowgoose Elite as my Catalac is not really suitable for the trans-pacific leg due to lack of water stowage.

Dont buy an ex-charter boat. They will be tired, and lots of bunks but no stowage.

Certainly be worth chartering one to see if you like it!, and more importantly whether your wife does.
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Old 01-05-2007, 11:49   #26
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Quote:
Originally Posted by GordMay
Interesting Article:
"Explosive devices designed for space rockets are being used to provide an emergency capsize-recovery system for an adventurer attempting to windsurf across the Pacific Ocean..."

Rocket explosives aid cross-Pacific windsurfer - 11 August 2003 - New Scientist
New Scientist
That's a SERIOUS board. So, he basically slept on that thing? How nuts is that?
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Old 01-05-2007, 15:37   #27
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Raphaela is a SHE.
Goto:
L'Odyssée du vent, le nouveau défi de Raphaëla Legouvello
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Old 01-05-2007, 21:52   #28
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Righting a multi

The Macgregor 36s were sometimes fitted with an airfoil shaped float at the masthead to keep the boat from turning 180. That would be a huge step in the right direction, preventing a complete rollover. Maybe an airbag rigged to inflate if the boat goes past 80 degrees. The idea of using a helium balloon or a kite to stand the boat up from sideways rather than turtle might be within the realm of possibility.

All that being said I think that going offshore in in a Piver 40AA would be a lot safer than sailing a CSY 33 or a C&C 29 anywhere.
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Old 01-05-2007, 22:29   #29
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I would like

to retract the previous statement about the C&C29.

Thanks
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Old 01-05-2007, 22:30   #30
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There's an article in multihull world #82 (the Aussie mag) where a pair of divers righted an upturned 10 m cat using a couple of airlift bags. It came up bow over stern. They seemed to be surprised at how easy it was to do.
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