Sailboats with ultra-high stability to high-stability

[Ceeman]

What brand does make ultra-high stability boats on a scale from 1 to 5.
In other words what kind of recent boat-design can withstand a total knockdown in high sea's?

1 ultra-high stability.

5 no stable at all

[tkeithlu]

Ahhh. Love your Insignia. But, it's not dependent on that. First, we're not talking about catamarans. They are fun but have the disturbing habit of floating upside down even better than they do right side up. Lots of initial stability, then none, then lots again.

Just about any ballasted keel monohull will return you upright once the leverage from the flooded sail is dispensed with. The issue is keeping water out until then, so that the ballast can indeed right you. This is why 40' cruising boats go through hurricanes, given good skippers. The amount of ballast was a design consideration in getting maximum performance out of the sails, and that's a bunch of righting moment.

Given that, more ballast jerks you upright while less makes for slower rolls. That's a matter of the meticentric height, the vertical distance between the center of mass and the center of bouyancy. Cruise ships go for a very small MH, so that they have a slow roll (no one is seasick) and they get more cabins up high. Some cheat, such as the Andrea Doria, which capsized, revealing a violation of international convention on MH. Flower class corvettes would roll on wet grass, but not a one was lost to weather in WW2. They would be a "4.9" on your scale.


I digress. In 1962 the racing yacht Doubloon did a 360 roll off Charleston SC. The first mate, tied to the helm and hanging below the fantail, knocked on the cabin door after 30 minutes. Needed clean underwear, I think. They buttoned up, and later that night, sans rigging, she did it again. She was towed into Charleston. She kept the water out.

The yacht Nadine, all 110 feet of her, sank off Scicly because she had an ordinary hatch on the foredeck, and then ordinary windows in the wheelhouse. She didn't keep the water out.

So, maybe someone knows of a 40' monohull to avoid for stability reasons. Otherwise, look for boats with strong ports and hatches. Have a good time, and keep the water on the outside.

[tkeithlu]

Here's a retrospective on the Doubloon capsizes.

https://www.tampabay.com/archive/199...-rocks-memory/

"Metacentric," not "meticentric". Old brain partially at work.

[Adelie]

Stability and capsize resistance are not the same things.
Stability is more or less righting moment. And it determines when you need to reef to keep from being overpowered.

Capsize resistance for monohulls is determined by roll moment of inertia.

So testing of boats has shown that a boat without its mast has more stability but is also more likely to be capsized. Counter intuitive but there it is.

[Joh.Ghurt]

Originally Posted by Ceeman

What brand does make ultra-high stability boats on a scale from 1 to 5.
In other words what kind of recent boat-design can withstand a total knockdown in high sea's?

You're probably asking the wrong questions, but to satisfy your curiosity: IMOCA 60 have to be tested for being able to survive capsizes (videos below) and many of them had severe knockdowns in the southern oceans and still continued thousands of miles to return to France.

90 degree test

180 degree test

[BugzyCan]

My Macgregor 26 is amazing in big storms. It sits in my driveway on the trailer. I rate it a 1, otherwise, out on the water, its probably a 6.

[CassidyNZ]

Very stiff boats are also very twitchy and not very sea-kindly. Also, a knockdown is a knock-down. Stiffness in the boat design is not going to stop a big wave rolling the boat on its side (or even all the way over), the forces are just too strong.

[fc59]

Stability is not enough.

There was a story of a former boat 35 ft Archambault A35 around the word. The boat capsized, but rerighted fast. So far so good ? No.

The mast was keel stepped. The mast broke during the capsize, severely damaging the deck. The boat had to be evacuated, and ultimately sank.

[ol1970]

Well after being on a Garcia 52, that is probably the boat I'd feel most comfortable handling pretty much anything that is survivable at sea (submarines not included).

[lvictorlucas]

I suggest you define in detail what you mean by "stability" more than "withstand a total knockdown in high sea's". For example does "withstand a total knockdown" mean losing the mast with what storm sails up and having to get on deck to cut it away.