Atlantic 57 Catamaran Capsized

[smj]

Originally Posted by Jim Cate

You know, if in fact this capsize was due to being struck by a waterspout, Chris W must be wondering how he pissed off the gods! A mean blow to the reputation of his work... Anna's demise could be attributed to crew error on a sensitive boat,but the extremely rare event of waterspout strike is truly the metaphorical "act of god" that the insurers are always on about!

"Why me" would be a reasonable question for him to be asking!

Jim

The crew also believe it was a waterspout. And the crew are also quite competent multihullers

[tp12]

As a lot of people have already said, a critical review of the two Atlantic capsizes that we have information on, Anna and Leopard, reveals that there is nothing wrong with the design and certainly no reason for Chris White's reputation to be smirched in any way. On the contrary, he's sought to understand the circumstances and posted information on his own website where other designers might be tempted to ignore and not comment on them. Chris stays involved and would appear to remain very helpful and an excellent resource for the many owners out there - both of these are strong positives for anyone considering a CW design, IMO.

I'm a big fan of the A57, great design.

[Cavalier MK2]

I'd think they would have heard the prop afterwards.

[Polux]

Originally Posted by smj

The crew also believe it was a waterspout. And the crew are also quite competent multihullers

Had you talked with the crew? A guy that talked with them, on another forum, said that "after a conversation with the crew of Leopard I am convinced the inversion was caused by a microburst or extreme squall."

Has the crew made any statement regarding that?

I saw that Chris white made a statement about the accident:

"The circumstances of the capsize are at once very clear and yet somewhat mysterious. There were three experienced, awake and alert sailors on board who all have vivid impressions of the event.

Leopard’s daily progress south had been similar to a trough ahead of an approaching cold front which meant that the wind was southerly and conditions somewhat unsettled. True wind speeds were running in the 23-28 knot range.

The forecast was for the front to overtake Leopard and the wind to shift to the west, so the crew was intentionally sailing slowly so they could obtain better conditions behind the front. There was no desire to sail fast and further away from the approaching favorable wind. The time was 1900, which means dark in November, and dinner prep was underway in the galley.

Leopard had the second reef in the mainsail and the smaller self tacking jib rolled to a #2 reef position. They were on starboard tack on a heading of about 150 degrees making about 7 knots in the puffs and much less in the lulls.

Professional captain Charles Nethersole has 14 years experience on the Atlantic 55 and 57 cats as well as decades of delivery and racing experience on a variety of offshore yachts. While he knows how t0 push a boat hard when it's required, he is also very good at throttling back when conditions warrant.

Charles had just altered course a little further off the wind and eased the sheets to near luffing in order to make work in the galley more comfortable in the head sea conditions. A few minutes later, he was back inside the pilothouse standing next to the helm station when he heard a sudden loud roar and immediately the boat started to rotate. He had no time to even hit the autopilot- off button.

Cooking dinner in the galley, Carolyn reported that she heard a loud roar coming from the starboard quarter. She stopped what she was doing to listen - wondering what it could be - before she was thrown against the refrigerator as the boat rotated. Crewman Bert, recounts that the capsize felt like “something supernatural”. Charles says that Leopard never took off forward as a fast cat typically would in the first seconds of a squall. She was immediately slammed into a sideways rotation.

Within a minute of capsize Bert swam out towing the still uninflated life raft and pulled himself onto the partially immersed underwing. He reports that the wind was normal at that point with no rain or indications of unusual weather.

It is still early in our evaluation of what happened but my own opinion is that Leopard was overtaken by a tornadic waterspout. When sailing offshore, I have seen at least a hundred of these small tornadoes extending down from clouds. Mostly they are short lived and don’t extend to the surface, at least in a visible form. But some do. And these can vary in intensity from small “dust devil” winds to an EF2 tornado (135 mph wind) with diameters of a few feet to 100 yards. This is the best explanation that I can come up with that fits the facts as we currently know them; a) Leopard was close to an approaching cold front, b) There were no rain squalls in the area, c) the roar, and d) the suddenness of the huge wind increase and the lack of strong wind immediately post capsize.

A capsize could be caused by a micro burst from a thunderstorm or large squall. These can be violent and dangerous.
..."

https://www.chriswhitedesigns.com/leopard-capsize

[Cavalier MK2]

Good questions as according to the account one towed the uninflated raft to the awash bridge deck, from there he would have been able to see any receding lights of shipping had that been the cause of the flip.

[Polux]

Originally Posted by tp12

As a lot of people have already said, a critical review of the two Atlantic capsizes that we have information on, Anna and Leopard, reveals that there is nothing wrong with the design and certainly no reason for Chris White's reputation to be smirched in any way. ....

It maybe so but I am not the only one thinking that keels are not a good idea on a very light and powerful cats. Most other designers prefer to use daggerboards for added safety allowing a better dynamic stability.

[belizesailor]

Originally Posted by Jim Cate

You know, if in fact this capsize was due to being struck by a waterspout, Chris W must be wondering how he pissed off the gods! A mean blow to the reputation of his work... Anna's demise could be attributed to crew error on a sensitive boat,but the extremely rare event of waterspout strike is truly the metaphorical "act of god" that the insurers are always on about!

"Why me" would be a reasonable question for him to be asking!

Jim

Yes, it does sound like a unprobable event that surprised a crew on an otherwise properly prepared boat. Even if they had been on station with sheets on hand, it sounds likely they would not have had time to avoid the weather event...be it freak wave or water spout.

[smj]

Originally Posted by Polux

Had you talked with the crew? A guy that talked with them, on another forum, said that "after a conversation with the crew of Leopard I am convinced the inversion was caused by a microburst or extreme squall."

Has the crew made any statement regarding that?

I saw that Chris white made a statement about the accident:

"The circumstances of the capsize are at once very clear and yet somewhat mysterious. There were three experienced, awake and alert sailors on board who all have vivid impressions of the event.

Leopard’s daily progress south had been similar to a trough ahead of an approaching cold front which meant that the wind was southerly and conditions somewhat unsettled. True wind speeds were running in the 23-28 knot range.

The forecast was for the front to overtake Leopard and the wind to shift to the west, so the crew was intentionally sailing slowly so they could obtain better conditions behind the front. There was no desire to sail fast and further away from the approaching favorable wind. The time was 1900, which means dark in November, and dinner prep was underway in the galley.

Leopard had the second reef in the mainsail and the smaller self tacking jib rolled to a #2 reef position. They were on starboard tack on a heading of about 150 degrees making about 7 knots in the puffs and much less in the lulls.

Professional captain Charles Nethersole has 14 years experience on the Atlantic 55 and 57 cats as well as decades of delivery and racing experience on a variety of offshore yachts. While he knows how t0 push a boat hard when it's required, he is also very good at throttling back when conditions warrant.

Charles had just altered course a little further off the wind and eased the sheets to near luffing in order to make work in the galley more comfortable in the head sea conditions. A few minutes later, he was back inside the pilothouse standing next to the helm station when he heard a sudden loud roar and immediately the boat started to rotate. He had no time to even hit the autopilot- off button.

Cooking dinner in the galley, Carolyn reported that she heard a loud roar coming from the starboard quarter. She stopped what she was doing to listen - wondering what it could be - before she was thrown against the refrigerator as the boat rotated. Crewman Bert, recounts that the capsize felt like “something supernatural”. Charles says that Leopard never took off forward as a fast cat typically would in the first seconds of a squall. She was immediately slammed into a sideways rotation.

Within a minute of capsize Bert swam out towing the still uninflated life raft and pulled himself onto the partially immersed underwing. He reports that the wind was normal at that point with no rain or indications of unusual weather.

It is still early in our evaluation of what happened but my own opinion is that Leopard was overtaken by a tornadic waterspout. When sailing offshore, I have seen at least a hundred of these small tornadoes extending down from clouds. Mostly they are short lived and don’t extend to the surface, at least in a visible form. But some do. And these can vary in intensity from small “dust devil” winds to an EF2 tornado (135 mph wind) with diameters of a few feet to 100 yards. This is the best explanation that I can come up with that fits the facts as we currently know them; a) Leopard was close to an approaching cold front, b) There were no rain squalls in the area, c) the roar, and d) the suddenness of the huge wind increase and the lack of strong wind immediately post capsize.

A capsize could be caused by a micro burst from a thunderstorm or large squall. These can be violent and dangerous.
..."

https://www.chriswhitedesigns.com/leopard-capsize

No, a friend talked to them.

[beiland]

Originally Posted by Cavalier MK2

I'd think they would have heard the prop afterwards.

?????
What does the prop have to do with this situation? They were under sail I believe,...not motoring.

[Cavalier MK2]

Originally Posted by beiland

?????
What does the prop have to do with this situation? They were under sail I believe,...not motoring.

Sorry B, the post I responded to was withdrawn. The chap was postulating that the boat could have been tipped by the bow wave of a freighter as long as everybody was cooking up theories. There were holes in the theory and he has apparently returned to his turkey dinner.

[neilpride]

Originally Posted by Polux

Where do you have got that number regarding a Lagoon only capsizing with full sails with over 45K winds?

In fact I think that it should be mandatory that information (the wind needed to capsize a given cat with full sail) on the information given by the builders regarding a boat, the same way on a monohull the AVS should be provided.

The truth is that is not mandatory and very few monohull builders give that AVS information (Halberg Rassy and Elan are among the ones that provide that information without having to be asked for) and I don't know of any cat builder that discloses the information regarding the wind needed to capsize a given cat with full sails.

Maybe I am wrong, did that information regarding the wind needed to capsize a Lagoon (+45K) come from the Lagoon shipyard? Or from the designers (VPLP)?

There are some simplistic formulas around that are supposed to calculate that (as there is some to calculate monohull AVS) but not only the data to use them cannot be assessed without precise calculations as the results given are not accurate and can be way off.

The calculation implies the use of a righting moment curve that will give the means to calculate the energy to capsize a cat and then the calculation regarding the rotational energy provided by a given sail design with a given area, that equals the energy needed to capsize the boat. Not an easy calculation even if not hard if you have all the data needed to perform it, but one that would take a considerable time if you don't have the computer programs to make those calculations easy.

All NA make these calculations when designing a boat and are based on that they will determine the sail area a given sailboat can carry safely, being a more conservative one if it is a cruiser, a more liberal one if a performance cruiser.

Getting back to those +45K that you say are needed to capsize a Lagoon with full sail, if it was so the boat should take the first reef at near 30k, the second at 40k, the third at 50k, only third reef and no frontal sail at 60K and bare poles over 75k, assuming that a cat should be reefed for gusts and not for real wind. This would give a very wide safety margin. I assume that those +45K were true wind so I am talking about true wind either.

In fact if we look at the manual of a Lagoon 400 we will see that they say that the reefs should be taken incomparably earlier. They give the wind speeds at one should reef in apparent wind that when going upwind is significantly less than the true wind and they say that in rough seas situation the reefs should be taken 10% earlier.

For a close hauled situation, were the apparent wind is substantially higher than the true wind, what they say is this:

" CLOSE HAULED TRIMMING (between 75 and 50° to true wind)
Given wind force in apparent wind
- From 0 to 16 knots: full sail ;
- From 16 to 20 knots: full sail ; the mainsail traveler moves up to 60
cm to windward of center, mainsail trimmed with a slightly more open
leech ....
- From 20 to 26 knots: 1 Reef, full Genoa
- From 26 to 30 knots: 1 Reef, 75% of the Genoa ;
- From 30 to 36 knots: 2 Reef, 60% of the Genoa
- From 36 to 45 knots: 2 Reef, 40% of the Genoa.
- From 45 to 55 knots: 3 Reefs main alone
- Over 55 knots: lie to, drag anchor or, preferably, scud bare poles

As you can see there is a huge diference on those numbers. I was talking about near 30K real wind (about 34k apparent) for the first reef while on Lagoon they consider 20K apparent for the first reef.

Those Lagoon reefing numbers don't add up with a catamaran that will only be capsized, with full sails by a wind of 45K, much less to a cat that "can be turned around in 45 kn with full sails on, decent margin".

Having wrong ideas about the wind a cat can sustain with full sails without capsizing can be very dangerous since it will induce a confidence based on unreal facts.

Note that I am not saying that a condo cat is not inherently more safer than a performance cat neither that it his easy to capsize a condo cat. In fact the numbers show, given the big disproportion in numbers between condo cats and performance cats, that the capsizes of cruising condo cats are much less frequent than the ones of performance cats and they tend to happen in smaller than 50ft cats, the smaller the more frequent. I don't think I have have heard about a bigger than 50ft condo cat capsizing, but I may be wrong.

The Lagoon reefing sails chart is quite funny, and last time I sail a Lagoon we get caught in squally weather from Canarie islands to Martinique , at 30 knts sustained gusting 38 under bare poles we make 9 knts in the lulls and 11 knts in the surfs,,, sails down,, prior to drop the sails we are just surfing at 14 to 16 , really scary and the AP permafrost in the surfs, so the whole structure act like a big sail...
45 knts 2 reefs and 40% genoa??? , wowowow.......

[belizesailor]

Originally Posted by neilpride

The Lagoon reefing sails chart is quite funny, and last time I sail a Lagoon we get caught in squally weather from Canarie islands to Martinique , at 30 knts sustained gusting 38 under bare poles we make 9 knts in the lulls and 11 knts in the surfs,,, sails down,, prior to drop the sails we are just surfing at 14 to 16 , really scary and the AP permafrost in the surfs, so the whole structure act like a big sail...
45 knts 2 reefs and 40% genoa??? , wowowow.......

Those big deckhouse are designed to double as a rigid spinnaker.

[arsenelupiga]

Originally Posted by neilpride

The Lagoon reefing sails chart is quite funny, and last time I sail a Lagoon we get caught in squally weather from Canarie islands to Martinique , at 30 knts sustained gusting 38 under bare poles we make 9 knts in the lulls and 11 knts in the surfs,,, sails down,, prior to drop the sails we are just surfing at 14 to 16 , really scary and the AP permafrost in the surfs, so the whole structure act like a big sail...
45 knts 2 reefs and 40% genoa??? , wowowow.......

that table is for windward - apparent wind. 45 kn app, probably 37 or so true.

Polux - 45 kn got from internet, from CF i think, no idea if correct. What I know is that 35 kn true and turning into wind with 1 reef is nonevent.

[neilpride]

Originally Posted by arsenelupiga

that table is for windward - apparent wind. 45 kn app, probably 37 or so true.

Polux - 45 kn got from internet, from CF i think, no idea if correct. What I know is that 35 kn true and turning into wind with 1 reef is nonevent.

Yes I guess its for windward work but Lagoons don't sail to weather quite well , then you have a beam reach and seriously I believe is a lot of sail for that wind speed...

[arsenelupiga]

Originally Posted by neilpride

Yes I guess its for windward work but Lagoons don't sail to weather quite well , then you have a beam reach and seriously I believe is a lot of sail for that wind speed...

looking at my own boat polar, boat manages 9 kn in 40 kn app at 45 deg app and <1m sea with 2 reefs as per manual, which gives 5.07 VMG and I am sure some drift.