Help save the lives of multihull sailors

> 10 years ago
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Buzzman
Buzzman
1 posts
1 posts
10 Jun 2013 3:51pm
Hey, all!

As many of you know - and have probably participated in - there is an ongoing debate about the 'seaworthiness' of multihull sailboats, whihc mostly revolves around the difficulty of self-recovery in the event of a capsize.

One idea to prevent this - originally proposed by Ian Farrier, the Kiwi trimaran designer - was to mount an inflatable airbag at the top of the mast that could inflate to prevent a multihull capsizing, or be inflated after inversion to assist with recovery.

On the "Multihull Collision Survivability" thread on BoatDesign.net forum this topic has been raised, and ideas proposed to develop a DIY version that anyone could do themselves (ie: not a commercial product).

But even these ideas need engineering solutions, and engineers cost money, which none of us have much of....

Then a plugged-in friend suggested "crowdfunding" as a possible solution....

So I've registered a profile on Quirky to attempt to raise crowdfunding to develop a prototype.

http://www.quirky.com/ideations/527033

Please Tweet, Facebook, email the link to everyone you know and ask people to 'vote' for the project.

'Voting' is free and doesn't involve any donation or commitment.....

Lots of sailors and their families will send you many warm fuzzies.....

And once the engineering is solved, and the plans produced, they will be published on the net for all to see and use!

Cheers
Mark
briann8300
briann8300
NSW
144 posts
NSW, 144 posts
10 Jun 2013 6:58pm
...sounds like a good idea....sure could have used one of these "capsize" devices about 30 years ago learning to sail Hobie cats in Gunnamatta Bay...after drifting upside down around the Bay for a few hours one day the Ferry guy eventually stopped and asked if I wanted help...or if not was there any chance I could quietly drown away from the Ferry route as I was causing concern amongst the passengers....
Darkspi
Darkspi
SA
171 posts
SA, 171 posts
10 Jun 2013 8:50pm
My random idea wouldn't be a inflatable airbag on the mast primarily cause in storms masts get broken and would be useless to rite a capsized boat and if you are gonna capsize a cat I would think it would be in a storm/heavy weather with far to much sail up. So failing an education in sailing how about a water ballasted Keel/s hulls . pump dry in fine weather fill in rough like a empty ship at sea
landyacht
landyacht
WA
5921 posts
WA, 5921 posts
10 Jun 2013 7:34pm
what about an airbag that is triggered by a counterweightor float when inverted? fix it at halfway or 3/4 way up mast to protect from lightning/broken mast. and a tripline down to the deck that needs to be activated before the counterweight(or float) can work
Lambie
Lambie
QLD
742 posts
QLD, 742 posts
10 Jun 2013 10:39pm
How about good training and a plan ?? Ive sailed a heap of cats inc hobie 14 / 16/ and 18's and had grief with all - meaning a capsize , but its all pretty easy to get them back up isnt it ?? - crew to the bow, rope over the top hull - right the sucker and back into the race - is that hard?? turn turtle and its a bit more of a plavar but the same - harden the fu788k up ??
Stuthepirate
Stuthepirate
SA
3591 posts
SA, 3591 posts
10 Jun 2013 10:26pm
Lambie said..
How about good training and a plan ?? Ive sailed a heap of cats inc hobie 14 / 16/ and 18's and had grief with all - meaning a capsize , but its all pretty easy to get them back up isnt it ?? - crew to the bow, rope over the top hull - right the sucker and back into the race - is that hard?? turn turtle and its a bit more of a plavar but the same - harden the fu788k up ??


I can see that working well with a 40ft Catamaran in the timor sea
gibberjoe
gibberjoe
SA
956 posts
SA, 956 posts
11 Jun 2013 12:28am

smaller boat, capercat had masttop float permenant, worked well i owned a couple, dont really think it could be scalled up for 40 footer, instant inflatable device seeems to have soom potential. It is a bit of a quandry but so far there has not been many lives lost though one is too many. Really have to live with the sea and manage ones exhubarence
Agent000
Agent000
161 posts
161 posts
10 Jun 2013 11:19pm
How about something to stop those poor monohull sailers from sinking somewhat like a lead weight ?
Rattlehead
Rattlehead
QLD
555 posts
QLD, 555 posts
11 Jun 2013 6:19pm



Been done years ago....
myusernam
myusernam
QLD
6158 posts
QLD, 6158 posts
11 Jun 2013 7:12pm
Buzzman said..

Hey, all!

As many of you know - and have probably participated in - there is an ongoing debate about the 'seaworthiness' of multihull sailboats, whihc mostly revolves around the difficulty of self-recovery in the event of a capsize.

One idea to prevent this - originally proposed by Ian Farrier, the Kiwi trimaran designer - was to mount an inflatable airbag at the top of the mast that could inflate to prevent a multihull capsizing, or be inflated after inversion to assist with recovery.

On the "Multihull Collision Survivability" thread on BoatDesign.net forum this topic has been raised, and ideas proposed to develop a DIY version that anyone could do themselves (ie: not a commercial product).

But even these ideas need engineering solutions, and engineers cost money, which none of us have much of....

Then a plugged-in friend suggested "crowdfunding" as a possible solution....

So I've registered a profile on Quirky to attempt to raise crowdfunding to develop a prototype.

http://www.quirky.com/ideations/527033

Please Tweet, Facebook, email the link to everyone you know and ask people to 'vote' for the project.

'Voting' is free and doesn't involve any donation or commitment.....

Lots of sailors and their families will send you many warm fuzzies.....

And once the engineering is solved, and the plans produced, they will be published on the net for all to see and use!

Cheers
Mark


are you taking racing cats? I thought with sensible skippers and sensible bruce factors it wasn't an issue? (cruising). At first I thought a mercury switch and airbag arrangement in the mast but that is likely to get torn off in a sea. You could simply have some tilt sensors in each hull that if the get over a preditermined level (i.e.40 degrees) it automatically opens the sheet block
myusernam
myusernam
QLD
6158 posts
QLD, 6158 posts
11 Jun 2013 7:19pm
When a cat does heel, its righting moment increases until the leeward hull carries the entire weight of the boat and the windward hull is flying. For practical purposes, designers consider this the angle of vanishing stability because from this point on, as the boat heels farther, righting moment diminishes rapidly as the center of gravity moves closer to the leeward hull. On our theoretical average boat, this angle is about 16 degrees. It's fairly general practice among naval architects to design cruising cats so that in theoretical static loading conditions, this point won't be reached in winds under 35 knots.


do cats even tip over anymore?
Rattlehead
Rattlehead
QLD
555 posts
QLD, 555 posts
12 Jun 2013 10:25am
myusernam said..

When a cat does heel, its righting moment increases until the leeward hull carries the entire weight of the boat and the windward hull is flying. For practical purposes, designers consider this the angle of vanishing stability because from this point on, as the boat heels farther, righting moment diminishes rapidly as the center of gravity moves closer to the leeward hull. On our theoretical average boat, this angle is about 16 degrees. It's fairly general practice among naval architects to design cruising cats so that in theoretical static loading conditions, this point won't be reached in winds under 35 knots.


do cats even tip over anymore?


Yes but mainly due to user error , you push any boat ( mono or multi ) too hard and your going to go for a swim.

GypsyDrifter
GypsyDrifter
WA
2371 posts
WA, 2371 posts
12 Jun 2013 11:39am
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blueseven
blueseven
QLD
59 posts
QLD, 59 posts
12 Jun 2013 8:45pm
Rattlehead said..

myusernam said..

When a cat does heel, its righting moment increases until the leeward hull carries the entire weight of the boat and the windward hull is flying. For practical purposes, designers consider this the angle of vanishing stability because from this point on, as the boat heels farther, righting moment diminishes rapidly as the center of gravity moves closer to the leeward hull. On our theoretical average boat, this angle is about 16 degrees. It's fairly general practice among naval architects to design cruising cats so that in theoretical static loading conditions, this point won't be reached in winds under 35 knots.


do cats even tip over anymore?


Yes but mainly due to user error , you push any boat ( mono or multi ) too hard and your going to go for a swim.



There is an old saying "multi-hulls don't tip over they sail over" . I agree,if you push any boat to far and you will come unstuck.
dinsdale
dinsdale
WA
1227 posts
WA, 1227 posts
12 Jun 2013 7:44pm
I always understood that ocean-going trimarans were far more prone to capsize than cats. Is this not so?
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