Capsized Atlantic 57 Salvaged

[Polux]

Originally Posted by SVNeko

Looks like it happened again:

http://www.cruisersforum.com/forums/...ed-175996.html

How many Atlantic 57 were made?
They seem very nice cats to me...but with a huge rig for a cat.

Expensive too:
http://www.yachtworld.com/boats/2011...a#.WDChDdKLRhE

[NoDramas]

Originally Posted by 2Hulls

Roger. I thought that was the case.

But back to your question mono vs multi heeling vs not heeling and rig loads. Multis DO heel - just not as much. But the physics is no different than monos. Both will heel an amount directly related to the load on the rig. The rig does not know the difference whether there's a little heel or a lot - it just feels the force that is balanced by the counter force applied by the hull(s) that balances the wind and water forces. So, I think, standing rigging design is irrelevant to amount of heel and should rely only on the correct engineering for the forces involved. Because of their narrower beam, mono rigs are usually far more complex than multi rigs simply because the multi rig designer can exploit the wider angles available to him/her. For example, on my boat there are just two shrouds and a forestay and one set of spreaders with one set of diamonds. As simple as a Hobie 18 (without the rotating mast).

2 Hulls Dave

Interestingly we have an Orma 60 racing Tri here in Auckland named Vodafone that is able to cant it's mast to windward up to 10 degrees. The reason for this, I'm told, is to counter the force lost by heeling and thus increase speed. Gregor Tarzan also noted in his book Catamarans that one must reef earlier on a Cat as they heel less and are therefore more sensitive to wind speed - which seems to me to say a similar thing. I would personally suspect that with a wind coming at 90 degree on the beam and 90 degree from the mast and the mast fixed in the ground you'd have more load than if the mast was canted 45-60 degrees away from the wind and therefore your rig load would be measurably less.

[NoDramas]

Originally Posted by NoDramas

Interestingly we have an Orma 60 racing Tri here in Auckland named Vodafone that is able to cant it's mast to windward up to 10 degrees. The reason for this, I'm told, is to counter the force lost by heeling and thus increase speed. Gregor Tarzan also noted in his book Catamarans that one must reef earlier on a Cat as they heel less and are therefore more sensitive to wind speed - which seems to me to say a similar thing. I would personally suspect that with a wind coming at 90 degree on the beam and 90 degree from the mast and the mast fixed in the ground you'd have more load than if the mast was canted 45-60 degrees away from the wind and therefore your rig load would be measurably less.

@2HullsDave just saw a later post which explained your position better.

[Factor]

Originally Posted by Polux

How many Atlantic 57 were made?
They seem very nice cats to me...but with a huge rig for a cat.

Yeah, what would Chris White know.

[Polux]

Originally Posted by NoDramas

Interestingly we have an Orma 60 racing Tri here in Auckland named Vodafone that is able to cant it's mast to windward up to 10 degrees. The reason for this, I'm told, is to counter the force lost by heeling and thus increase speed. Gregor Tarzan also noted in his book Catamarans that one must reef earlier on a Cat as they heel less and are therefore more sensitive to wind speed - which seems to me to say a similar thing. I would personally suspect that with a wind coming at 90 degree on the beam and 90 degree from the mast and the mast fixed in the ground you'd have more load than if the mast was canted 45-60 degrees away from the wind and therefore your rig load would be measurably less.

Yes, that seems pretty much obvious and the difference would be way less.

I did not know of that canting mast but I do know the the ORMA had big problems with capsizes with heavy winds. I remember a transat where several were capsized bare polled and I wonder why that one on Australia seem to have less problems in what regards that. That canting mast may explain why.

[Polux]

Originally Posted by Factor

Yeah, what would Chris White know.

I don't know, somebody said that Chris White had said that 11 Atlantic 57 were made and two capsized. It is a frightening average. Maybe such a light boat pointed mostly for cruising should have a smaller rig.

As you know the percentage of capsizes on heavier cats with smaller rig as nothing to do with these numbers.

[clockwork orange]

There will always be capsizes with performance cruising cats because they are purchased more by those who can afford them rather than those who have come up through other highly powered multies like beach cats that will teach the lessons needed to sail such craft safely. Wharram cats virtually never capsize because they have very conservative rigs. I have a very old production beach cat (Pacific cat 19, began production in 1959) that has a huge sail plan but it is very low and combined with being very heavy at 550lbs (solid bridgedeck) it has very little tendancy to capsize in any amount of breeze but still sails very fast, in fact it is one of the best mannered boats of any type that I have sailed in over 50 years of sailing. The point is if you want to have a lot of sail and be reasonably safe it better be low down.

Steve.

[neilpride]

Originally Posted by Polux

I don't know, somebody said that Chris White had said that 11 Atlantic 57 were made and two capsized. It is a frightening average. Maybe such a light boat pointed mostly for cruising should have a smaller rig.

As you know the percentage of capsizes on heavier cats with smaller rig as nothing to do with these numbers.

Yep, I see the rig in the A57 a bit to much to, also I don't know the weight? somehow I read somewhere 25000 pounds ....A Lagoon 440 weight around 26700 ... I mean tall hig performance rig , lightweight construction, figurate....

[Polux]

Originally Posted by clockwork orange

.... Wharram cats virtually never capsize because they have very conservative rigs. ...
Steve.

Yes Wharram claims that on his site but it is not really true:

As Martin Schoon said "Wharram cats have capsized but as virtually no boat built to plans from Jim Wharram have been built *exactly* as in the plans (Wharram himself invites his customers to be creative) Mr. Wharram can always claim that the capsized boat was not a Wharram cat. So a more correct statement would be: Extremely few Wharram cats have capsized."
https://groups.google.com/forum/#!to...0%5B151-175%5D
Here you have three cases:
"Whip-Poor-Will" (Tane), Long Island Sound, USA, 1975
"Kauka" (Tane), Waiheke Island, NZ, May 29 1979
And more recently:
"35 foot Wharram Tangaroa capsized in Wellinton Harbour New Zealand some years ago. The owner of the boat had all sail set in a wind gusting to 32 knots."
Classic capsize | James Wharram Designs

The Wharrams sail pretty poorly upwind, according one that circumnavigated with one not being able than doing better than 60º upwind but they are heavy, beamy and they have very low windage, a thing that cannot be said about condo cats, even if the beam and weight are common characteristics.

[clockwork orange]

You did see that I said "virtually", right? There are "probably" more wharrams out there doing long voyages than any other cat, they have been doing it for decades before there were any viable production cruising cats and very, very few have capsized. Also a lot of them that undertake long distance cruises are much smaller than the typical cruising cats we are used to seeing today. I have personally only sailed on one, a Tangaroa, which was a long time ago and we did not go upwind, it was just a delivery from launching of the beach to its mooring about 10 miles away but it reached as fast as a fast 45 ft racing monohull of the day that we passed and I remember a very nice smooth ride with the flexible connectives. I don't see them as particularly heavy for a cruising cat, the Tiki 38 for example is listed as having a weight of 6600lbs with a rather optimistic payload of 4400lbs. I expect that upwind performance would not be a strong point without boards but then from all accounts condomarans don't seem to score well either but it does not seem to deter folks from buying them. I sail my beachcat in a group of mostly Hobie 16s and am actually quite impressed how they go upwind without boards as long as there is breeze, we will beat them in a long beat with a combination of pointing a bit higher with boards and tacking quicker but we have a very low aspect rig and old sails but in a recent fleet race we sailed a 5 mile beat with an identical vmg as the 2 J24s in the race, we were a little lower and a little faster in the light breeze, more breeze and we would have pointed higher and been a lot faster. The A cat in our group is much much faster and out points all the racing monos by a lot, ruthless efficiency.

[boatman61]

Originally Posted by Polux

Yes Wharram claims that on his site but it is not really true:

As Martin Schoon said "Wharram cats have capsized but as virtually no boat built to plans from Jim Wharram have been built *exactly* as in the plans (Wharram himself invites his customers to be creative) Mr. Wharram can always claim that the capsized boat was not a Wharram cat. So a more correct statement would be: Extremely few Wharram cats have capsized."
https://groups.google.com/forum/#!to...0%5B151-175%5D
Here you have three cases:
"Whip-Poor-Will" (Tane), Long Island Sound, USA, 1975
"Kauka" (Tane), Waiheke Island, NZ, May 29 1979
And more recently:
"35 foot Wharram Tangaroa capsized in Wellinton Harbour New Zealand some years ago. The owner of the boat had all sail set in a wind gusting to 32 knots."
Classic capsize | James Wharram Designs

The Wharrams sail pretty poorly upwind, according one that circumnavigated with one not being able than doing better than 60º upwind but they are heavy, beamy and they have very low windage, a thing that cannot be said about condo cats, even if the beam and weight are common characteristics.

Polux.. the old Classic Designs were heavy.. but remember he drew these plans up in the 60's for use with easily available materials for the home builder.. the ones listed above are all in that category.
He's drawn a few plans since those and his Tiki and Pahi range using stitch and glue methods have resulted in lighter better performing boats.. they can even tack..

[double u]

fwiw:
Tangaroa MkI (cutter, mastposition 50% WL, mastlength 11m) beamreaching in +25kn, yankee, staysail, main, seas beam on, fairly steep, 2-3m & increasing, fetch ~20 nm (can't remember exactly, African coast very low on horizon), one wave threw windward hull so far up that we seemed to teeter, stuff that never had moved in >6 years of rtw got thrown about inside, boat fell back on "even keels", we kept going under reduced sail
conclusion: it's unnecessary for a wave to actually lift the windward hull high enough for a capsize, it is sufficient if it imparts enough rotational enery to the boat that it keeps rotating until stability is negativ (much like you can get a chair to topple by giving it a short but strong shove without actually pushing it beyond the point of no return)
(this was near the end of our 7 year rtw, so neither we nor boat was untried. I had increased beam to slightly >50%Loa over the original, boat was heavily laden)

[beiland]

Originally Posted by clockwork orange

There will always be capsizes with performance cruising cats because they are purchased more by those who can afford them rather than those who have come up through other highly powered multies like beach cats that will teach the lessons needed to sail such craft safely. Wharram cats virtually never capsize because they have very conservative rigs. I have a very old production beach cat (Pacific cat 19, began production in 1959) that has a huge sail plan but it is very low and combined with being very heavy at 550lbs (solid bridgedeck) it has very little tendancy to capsize in any amount of breeze but still sails very fast, in fact it is one of the best mannered boats of any type that I have sailed in over 50 years of sailing. The point is if you want to have a lot of sail and be reasonably safe it better be low down.
Steve.

Steve

Perhaps revisit a previous posting of mine on this subject thread, #292

Shorter Rigs, Lower Aspect Ratios
I have in the past suggested that Anna might not have capsized if she had been carrying a lower aspect rig.

Here is a diagram of my 'single-masted ketch compared to a fractional rigged sloop of the SAME sail area. My mast is 15' shorter in height than the sloop,...probably a greater reef that the first reef on Anna.

[SVNeko]

Maybe it's time to rethink the fractional rigs so common with cats. Also, I think moving the mast aft for a higher aspect main and larger headsail with an overall lower CG is interesting. A little less radical than Beiland's aft mast rig.

[double u]

if there is enough rotational energy transmitted from a wave to the boat ("right" combination of steepness of face & speed of propagation) any cat with capsize, rig or no rig!