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Old 30-08-2010, 13:43   #361
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As you point out - once you "blow" the mainsheet gear you have a completely uncontrollable boom. That is still carrying full sail.

I am not convinced at all, even with all the thoughtful and reasoned responses, that letting go the boom automatically is the right thing to do.
Yes I agree completely, having an automatic boom release would be extremely dangerous for any number of reasons and I would never feel comfortable sailing knowing that such a feature was built into the boat.

My point was that if you were to have some sort of fuse built in, I would think having elastic restraint would be the only way to prevent serious damage... sure the boat was built to gibe, but how many of you are gibing around in 60+ knots with enough sail area up to flip your boat??

I'd agree with Factor on reefing. An unreefed main on these 'performance oriented' cats seems equivalent to a spinnaker or whatever on monos; great for light wind but are you going to keep it flying as the wind picks up?

But who knows, maybe a fuse would save a couple cats from flipping... I certainly wouldn't want to be anywhere near it when it goes though.
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Old 30-08-2010, 13:46   #362
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Looks like Anna is on the way to NZ via Niue on the same ship that rescued the crew. Photo from The Tahina Expedition
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Old 30-08-2010, 14:43   #363
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Originally Posted by Eleven View Post
The reason this Cat flipped is because the LEE daggerboard was deployed.

As the Windward hull lifts a board deployed on that side allows the boat to slide and slew around the rudders so turning mainly downwind, the recommended tip avoidance manouvre.
It wasn't a bad design, an over complex boat or anything else, just that the WRONG DAGGERBOARD WAS DEPLOYED.

I think I saw early in this thread that the boards were asymmetric section, ie designed to lift more one way than the other. Had they been fitted to the right side? Did this crew fit them? What is the designers view on this.

And take note, you dagger cat men, an UPWIND DAGGERBOARD IS SAFE.
I still am not all through with all these postings, find it very interesting .. actually: VERY, VERY(!) interesting! especially since I have always been a "mono" only currently thinking of cat's and tri's.

One thing I'd like to clarify inbetween:
You are right: On this picture http://www.latitude38.com/lectronic/...a%2001-121.jpg BOTH daggers are "up" *ehh* "down" but while reading all these partly quite confusing and a bit too scientific postings for my little brain to comprehend, I have downloaded the youtube video (slow inet connection as usual) and during the rescue it seems only one daggerboard had been deployed and even that only about half way??
So how can it be that (a) on the foto both daggers are "up" and (b) can someone explain to me -in a bit more simple words- why it would matter if both were down?
I always thought that one would use them only when tacking and I would have (prior to reading this thread) put them both down and left them there not having to bather to switch the deployed one on top of every tack?
*hmmm*

Maybe I will find the explanation when reading on - am on page 18 currently, so y' all forgiveness please if I did shoot my big mouth off too soon!
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Old 30-08-2010, 14:55   #364
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The owners say the lee board was down, which is what you see in the rescue video. When the boat hit the reef both boards were pushed 'down' (eg up with the boat upside down) by the grounding.

One theory goes that with both boards up, the boat would be more likely to slide sideways rather than flip, as lowering a board lowers the center of lateral resistance and increases the flipping lever arm. I have never see a good analysis of this, but my guess would be that the boards are so small compared to the total area of submerged hull and fixed keel it will make little difference if they are up or down.

I am glad to see the boat recovered and probably on the way to being rebuilt. That makes me happy.
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Old 30-08-2010, 14:57   #365
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Chain of Errors

This is slightly off from the current direction of the thread; however, as I think about the capsizing, I can’t help but think of training that I have received as a pilot. Chris White mentions flying in his analysis of the event and for good reason. I am not a commercial pilot, but I have flown for over forty years in a variety of aircraft from simple tail draggers to sailplanes to jets.

There are three parts of training that have always jumped out at me: 1) knowing your systems; 2) avoiding complacency; and 3) breaking the “chain of errors?” When you train at a school like Flight Safety, they combine class work with simulator time – it can be intense, as the simulators are full motion and you can really “feel” like you are flying.

Relating to our shared world of ocean sailing, perhaps some discussion from the group on what they do to address the following areas might be useful:

1) Many of us learn our systems through trial and error. Whenever I am on a new boat, I feel somewhat adrift (pun intended). It takes a pretty long time for me to feel comfortable.

I go to Flight Safety at least once every year for a week and “relearn” the aircraft systems. Airline pilots go to their training programs at least twice a year – for each model of plane that they fly!

For my boat, sure I do some drills (man overboard, for example), but do I do enough? For myself, I can say “no;” I am too busy sailing – color me lazy. Can you think of practical ways to make the systems side of learning about and training on our boats easier and more effective? Perhaps picking a handful of critical scenarios and preparing a written plan for each would be a good exercise – then review them before each offshore trip?

2) Many of you have probably heard of the boiled frog syndrome. It is said that, if you put a frog in a pot of boiling water, it will jump out. But … if you put a frog in a pot of cold water and slowly turn up the heat, it will cook to death. (I don’t know if this is true and I have no intention of testing it) I, for one, can get complacent. For me, at least, there is a little warning bell that starts ringing as a situation becomes more tenuous. Of course, experience refines the trigger point of the warning bell, which is entirely appropriate.

Sadly, experience can drift into complacency and tends to quiet the bell down, which is dangerous. Are there ways to amplify the noise level on the “warning bell?” For example, a physical action, such as raising a little red flag in your cockpit, whenever you are nervous about anything, might trigger more of a reaction, especially when we are tired. Maybe this is just too silly.

3) It is rarely, if ever, the first problem or error that kills you. Pilots are trained to break the “chain of errors.” When humans are highly stressed, adrenaline floods through our systems. While this is an important physical response, it also has some negative effects. For example, every pilot, who has been stressed in a simulator, can appreciate how fixated you can become on one input or task when the aircraft needs you to “scan” many. I personally have been so focused on a popped circuit breaker that I lost track of the attitude of the plane (e.g. I went upside down) and … the circuit breaker was non-critical! Scanning is drummed into pilots for just this reason.

Checklists are used to break the chain of errors. Typically, there are memory items on every checklist that must be memorized, because sometimes you don’t have time to pick up the checklist. Chris White has suggested S.T.A.C.K.S. as one mnemonic to help in these circumstances. How do you break the chain of errors and broaden your scan when it hits the fan?

I am NOT for a second suggesting required training or licenses here, both of which I would personally dislike intensely. The point of my posting is to stimulate useful and practical ideas in these three areas. Any thoughts?
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Old 30-08-2010, 15:22   #366
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Originally Posted by Dragon701 View Post
I can’t help but think of training that I have received as a pilot.

1) Whenever I am on a new boat, I feel somewhat adrift (pun intended). It takes a pretty long time for me to feel comfortable.

2) , experience can drift into complacency and tends to quiet the bell down, which is dangerous.

3) It is rarely, if ever, the first problem or error that kills you. Pilots are trained to break the “chain of errors.”
That is a five star post.

I know and have made first hand all three of those errors many times and I have thought about and tried to figure ways to minimize all three but have essentially failed.

For #1: we try very hard to get out of the marina or calm anchorage and to a rolly anchorage, and we try hard to make one overnight sail before any longer passage, to get us over some of the first 'day mistakes'. But it still takes me 3 to 5 days before I really have my sea legs and are 100% ready to deal with a crisis, and we still make all sorts of silly mistakes the first day or two.

For #2: It was discussed previously, but we cycle between being complacent, getting slapped down, then being really careful, until we have been good so long we get complacent again. I have a series of disaster stories I keep around, including some of our own, and try to read them periodically to remind me how easily very experienced and skilled people can get into trouble. But so far it has not stopped me from making stupid complacent mistakes now and again.

For #3: we do have various checklists, like for when we leave on passage and when we make landfall, but usually our mistakes occur during incidents we don't have check lists for.

I was a, less accomplished that you obviously are, private pilot once back in the day. I did not have the same problems I have with sailing. I always felt pretty comfortable immediately in the cockpit and did not have the 'getting sea legs' issue, and I was always fearful enough not to get complacent. It was always pretty obvious to me I could fall out of the sky and die, which is not so obvious on the boat.

You have identified three really important problems/opportunities and I hope someone has a good solution or technique or two for me to learn.
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Old 30-08-2010, 16:45   #367
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Looks like Anna is on the way to NZ via Niue on the same ship that rescued the crew. Photo from The Tahina Expedition
I wonder how long before a new CF member appears
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Old 30-08-2010, 18:11   #368
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The owners say the lee board was down, which is what you see in the rescue video. When the boat hit the reef both boards were pushed 'down' (eg up with the boat upside down) by the grounding.

One theory goes that with both boards up, the boat would be more likely to slide sideways rather than flip, as lowering a board lowers the center of lateral resistance and increases the flipping lever arm. I have never see a good analysis of this, but my guess would be that the boards are so small compared to the total area of submerged hull and fixed keel it will make little difference if they are up or down.

I am glad to see the boat recovered and probably on the way to being rebuilt. That makes me happy.
Haha sorry to keep quoting you, all your posts are so interesting I can't help it. Forgive me for being a forum stalker.

Aside from lowering the center of resistance, daggerboards induce a capsizing moment. If Anna was moving at a good pace through the water, in addition to increasing the lateral resistance it could have been imparting good bit of rotational force.

Not sure if it would be enough to make or break the situation, but another thing to think about.

(If anyone knows the rough shape and size of the daggers and the speed I'd be happy to figure out the amount of lift it'd generate--at some reasonable angles of attack--to see if it could have been a factor. Just can't go searching for it now...the lady is giving me a mean look which mean's I must go!)
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Old 30-08-2010, 18:25   #369
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Attachment 18794

Looks like Anna is on the way to NZ via Niue on the same ship that rescued the crew. Photo from The Tahina Expedition

Thanks for posting this Dave, I've been hanging out for an update about what the latest was with Anna. It will be interesting to follow her through the repair process until the time that she hits the water again after being repaired.

Steve
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Old 31-08-2010, 07:12   #370
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The owners say the lee board was down, which is what you see in the rescue video. When the boat hit the reef both boards were pushed 'down' (eg up with the boat upside down) by the grounding.
Yup, thanks, I did read the account once again myself and found that being stated there.

Even so I still don't fully comprehend the "mechanics" behind "never have the lee-board down" .. I start to catch the drift.
Correct me if I am wrong, but windward hull goes up, drag from water consequently nil - while lee hull is in the water and has all the drag as it is. If on top of that there is "NO dagger" on the windward to maybe "keep in touch with the water" - while the "Lee-dagger" is down, that will further increase the drag on the lee hull additionally.
Consequence something like the steering of a tank with the "windward chains" going full speed and the "leeward chains" put to a "full stop"?
(With the difference of course that the tank wont capsize - but it will turn sharply and that very same momentum will cause a multi to flip?)

Seems like everything I "know" & "learned" is of little value when it comes to cat sailing... hmm, that makes me: "Just thinking"
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Old 31-08-2010, 07:38   #371
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Thanks for posting this Dave, I've been hanging out for an update about what the latest was with Anna. It will be interesting to follow her through the repair process until the time that she hits the water again after being repaired.

Steve
Steve,

I hope I'm wrong, but I doubt very much that Anna will be repaired. From what I understand she washed across a reef losing her rig, cabin and probably much of her deck hardware and part of her deck. The stern sections are in a bad way and, with her lovely sheer, the bows are likely damaged as well. I just don't see repair as being cost effective, but like I said, here's hoping I'm wrong.

Mike
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Old 31-08-2010, 09:11   #372
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On automatic sheet release mechanisms - there have been many designs over the years, I've read about a bunch of these. No practical experience though. They are unpopular due to "false positives". Here's one that's electronic, triggered by a mercury switch: Iroquois Owners Association Newsletter July 1995

On leeward boards - you don't want the leeward board down as the boat can trip on it, instead of sliding along the waves. Not a problem with the windward board as it won't lever the boat out of the water, but instead be more like a brake.

On the boiling frogs - That metaphor is inaccurate. The frog would try to escape the water as the temperature slowly rises. They have central nervous systems same as we do and would feel pain.
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Old 31-08-2010, 11:17   #373
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According to the story on the Blogsite

The Tahina Expedition

"We also heard the crew of Anna were having trouble getting insurance to pay for the loss. Apparently their policy required a crew of 3 when on blue water cruises. Not that it would have made any difference in this case."

This could be a brutal loss if the insurance doesn't pay. If you have a policy requirement like most do, then that was a HUGE risk to be taking. If the insurance pays, we all end up sharing the cost. I have mixed emotions about that.

I hate to see anyone have to bear that loss, but I also believe we all have a responsibility to adhere to the requirements we agreed to. The biggest point I guess I am making is that everyone needs to consider the risks from all angles. I doubt the crew of Anna ever even considered the insurance angle when deciding to sail with a crew of 2.

This entire episode has certainly opened my eyes to many different aspects, and will probably (hopefully) be a lesson I will remember the rest of my days.
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Old 31-08-2010, 11:29   #374
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Cats flip, and monohulls sink. The law of the sea.
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Old 31-08-2010, 11:29   #375
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On leeward boards - you don't want the leeward board down as the boat can trip on it, instead of sliding along the waves. Not a problem with the windward board as it won't lever the boat out of the water, but instead be more like a brake.
Yes a lee board can trip the boat in waves. I don't think the mechanism is just the increased lateral plane and lowered ce but also has to do with the geometry of the board or keel. At any rate, there is tank work that suggests an increase in capsizes if a keel/board is deployed. (eg.http://www.wumtia.soton.ac.uk/papers/CSYS2001BD.pdf "The addition of the keels appeared to result in a slight increase in the vulnerability to capsize.")

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On the boiling frogs - That metaphor is inaccurate. The frog would try to escape the water as the temperature slowly rises. They have central nervous systems same as we do and would feel pain.
Amazingly enough there is a wiki on this.... Apparently the enlightenment was nasty...

Tom
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