Risk of capsizing a Lagoon 380 and reefing

[Cloroxbottle]

Originally Posted by NSfooter

Not sure what you mean by 10%, but perhaps you mean 10 degrees. All vessels have an angle where their "stability" disappears. This is found on a GZ curve. While it is true that the angle is less for a cat than a mono, a cruising cat is likely about 70 degrees, so there is no need to worry about angle of heel.

The angle is much, much less on a cat than a monohull and if you get anywhere near 70 degrees, there's no recovering. There's a website that has all this information on it, along with the wind needed to capsize different model cats but I forget the url at the moment. But in general, from what I recall at 20 degrees of heel you're going over for certain in most.

[Tupaia]

Originally Posted by Cloroxbottle

The angle is much, much less on a cat than a monohull and if you get anywhere near 70 degrees, there's no recovering. There's a website that has all this information on it, along with the wind needed to capsize different model cats but I forget the url at the moment. But in general, from what I recall at 20 degrees of heel you're going over for certain in most.

There is an article by James Wharram that explains Stability in simple terms


https://www.wharram.com/articles/how...aran-stability

[CaptainRivet]

Originally Posted by Tupaia

Probably not as efficient as "Kite Boat Systems" www.Kite-boat.com or Sky Sails www.skysails-yacht.com that both use parafoils but looks a whole lot simpler and cheaper.


My only concern would be the length of line from the mast head and the force that could be exerted high up if the deck level line was released or let go by accident. Does the mast head line attach to the bridle of the parachute or the rim and is this line loose when the para is flying?



I assume you could have an extra length of line equal to the height of the mast to keep things off the deck that attached to the existing spinnaker halyard. But that would still leave the parachute lines themselves to deal with.

Kite boat system is overly complicated. I would have been part of a crew from La Spezia Italy to Hawaii 2 years ago on a 65ft powerboat that had that system on. The whole crew insisted to test it thoroughly so we get familiar with the system. During test to Monaco and back it showed the theory is nice but actively steering that kite up in the air especially in wind shifts is at least problematic…we already lost one kite in condition of up to 25kn AWS and to retrive that broken kite was impossible so we needed to cut lines. For me that was not safe to rely on that and left ship as we partly had to fully rely on that system as it was impossible to have that much diesel on board for eg atlantic crossing.

The round sail is super simple (and needs a mast), cheap and cares about itself and the boat. You also don‘t need a bowsprit. The only thing you need is block and shackle to connect it somewhere to the bow of the boat, in 99% it goes somewhere on the existing bow roller.
Forget to connect extra lines, they tend to tangle and make things complicated.
Before you use the round sail the first time, you connect the center of the roundsail somewhere around the mast to the deck and hoist it with the halyard. When it’s fully up you have the reference point to mark on your spi halyard where nothing can happen anymore, as when it comes down it ends up on the deck. I marked a 2nd point where it’s just above seelevel so that’s minimum point to reach when it stalls because eg wind dies suddenly or the little ropes rips because you overloaded it.
So when you wanna retrieve it you simply whinch the spi halyard to that mark (or when it accidentally stalls due to any reason you get in the spi halyard as fast as you can above seelevel or better decklevel mark and nothing bad can happen anymore), then bear away 30-40 degrees and deploy Genua and roundsail is in the windshade of Genua starts to stall and comes slowly down and slides on the Genua down. It cannot fall into water, the worst that can happen it’s inflating and you have to bear away a bit more and it will come down again. Like this Centre of sail will be always lowest point, so as soon as you can Grab the center loop of the sail, pull it down and connect it anywhere closeby to deck and your set, it cannot inflate anymore and you have all the time in the world to pack it in its bag or I actually just wrap it around the cap shroud, secure it with 4-5 Velcro straps and connect Centre to the middle cleat nearby. Like this I have it ready to be deployed again in less then a minute. It cannot open as the center is connected to deck.
And in absolute worst case of all bear way 90 degrees and cut both lines and will fly away in sideways of you, so you not to run over it and you lost 1000Euro+max. 70m 12mm rope…cheaper then to repair any furled downwindsail.

[CaptainRivet]

Originally Posted by Tupaia

There is an article by James Wharram that explains Stability in simple terms


https://www.wharram.com/articles/how...aran-stability

Great article, thanks.

[Tupaia]

Originally Posted by CaptainRivet

Before you use the round sail the first time, you connect the center of the roundsail somewhere around the mast to the deck and hoist it with the halyard.


When it’s fully up you have the reference point to mark on your spi halyard where nothing can happen anymore, as when it comes down it ends up on the deck. I marked a 2nd point where it’s just above seelevel so that’s minimum point to reach when it stalls because eg wind dies suddenly or the little ropes rips because you overloaded it.


So when you wanna retrieve it you simply whinch the spi halyard to that mark (or when it accidentally stalls due to any reason you get in the spi halyard as fast as you can above seelevel or better decklevel mark and nothing bad can happen anymore), then bear away 30-40 degrees and deploy Genua and roundsail is in the windshade of Genua starts to stall and comes slowly down and slides on the Genua down.


It cannot fall into water, the worst that can happen it’s inflating and you have to bear away a bit more and it will come down again. Like this Centre of sail will be always lowest point, so as soon as you can


Grab the center loop of the sail, pull it down and connect it anywhere closeby to deck and your set, it cannot inflate anymore and you have all the time in the world to pack it in its bag or I actually just wrap it around the cap shroud, secure it with 4-5 Velcro straps and connect Centre to the middle cleat nearby. Like this I have it ready to be deployed again in less then a minute.


It cannot open as the center is connected to deck.
And in absolute worst case of all bear way 90 degrees and cut both lines and will fly away in sideways of you, so you not to run over it and you lost 1000Euro+max. 70m 12mm rope…cheaper then to repair any furled downwindsail.

Thanks for the description.


When you say center of the round sail do you mean where the shrouds meet the risers or at the top of the canopy where the vent is?

[CaptainRivet]

Originally Posted by Tupaia

Thanks for the description.


When you say center of the round sail do you mean where the shrouds meet the risers or at the top of the canopy where the vent is?

A the top of the canopy, there is a little loop.
Thats also where you can connect a collapsing line as the designer describes as an alternative to get it down. Pull the line and it collapses but that line causes a lot troubles as it will sooner then later tangle around the other two causing troubles. Done that and won't recommend it. Its really easy even singlehanded in 30kn to get it down with the genua method on a cat.