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Old 05-08-2010, 15:08   #121
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Originally Posted by Southern Star View Post
I am no engineer, but what about a line clutch placed in front of the winch which can be mechanically locked down, but which uses an electronic weigh scale that trips a microswitch, releasing the cam when a certain pre-set, but adjustable load is reached.
I think it will be hard to do this measuring main sheet force. I could well be wrong and I haven't done any analysis but I think on most boats there would be a lot of false positives because of shock loading in a system that would be able to prevent most capsizes. A delayed system to reduce false positives might allow a capsize where the force is just high enough to sail the boat over. My guess is that it would be more productive to look at some kind of dampened clinometer. I think it is heel wrt local gravity that we're concerned with not force so why not measure it directly?

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Old 05-08-2010, 15:22   #122
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notice my sails are down
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Old 05-08-2010, 15:37   #123
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Originally Posted by tsmwebb View Post
I think it will be hard to do this measuring main sheet force. I could well be wrong and I haven't done any analysis but I think on most boats there would be a lot of false positives because of shock loading in a system that would be able to prevent most capsizes. A delayed system to reduce false positives might allow a capsize where the force is just high enough to sail the boat over. My guess is that it would be more productive to look at some kind of dampened clinometer. I think it is heel wrt local gravity that we're concerned with not force so why not measure it directly?

Tom
Design of such a system as you suggest is a lot easier than many might assume. The sensitivity dampening existent in off the shelf micro piezo gyros is MUCH more than sufficient for the intended use and can accurately measure on both axis'. They are dirt cheap, and can be attached to any type of servo/solenoid of ones choosing at a total parts cost of well less than $500. These are robust, field tested,abundantly available pieces of solid state electronics which are easy to setup and operate.

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Old 05-08-2010, 15:55   #124
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G'day all,

On the auto release device -- as I recall, Donald Crowhurst was touting just such a device on "Teignmouth Electron (sp?)" when he set out on that ill-fated RTW race back many years ago. HE was a nutcase for sure, but the idea wasn't so bad, and modern electronics have apparently made such a safety device quite possible.

And, from the above description of "Anna's" design, she was a thinly disguised race boat. One wonders about the advisability of such a sensitive design in a short handed cruising boat... but I bet she was fun while she lasted!

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Old 05-08-2010, 16:08   #125
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Design of such a system as you suggest is a lot easier than many might assume. The sensitivity dampening existent in off the shelf micro piezo gyros is MUCH more than sufficient for the intended use and can accurately measure on both axis'.
Very, very cool. But I wonder if we really want a gyro? I think that it would work well in flat conditions but at sea the waves may be large enough that the distinction between "down" as measured by a plum bob and a gyro could become significant? Dynamic stability is complex but generally I think normal to the surface of the water is the down we're looking for. I'm thinking maybe a clinometer with some small amount of damping that sets off a buzzer at say 7 degrees and releases the sheets at 12 (or some such) might be better... I'm not sure how needed such a device is and it may provide a false sense of security (eg. it would still be nuts to have a full main up while power reaching reaching on a boat where the boom will be held by the shrouds). Still, if it's not too very expensive or fiddly I"d probably buy one for the 1:1e10 time that it could save the boat and think it money well spent...

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Old 05-08-2010, 16:38   #126
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And, from the above description of "Anna's" design, she was a thinly disguised race boat.
If not having a genset makes boats "racing" then there are a lot of slow race boats out there but many of them are kinda slow and conservative ... Actually, I don't have any idea what the sailing displacement of Anna was but unless they were able to bring it in well under design specs I wouldn't consider her a race boat. In any case, with a 28 foot beam she has a lot of stability and the design has a relatively short mast so I would expect she could have been rigged down effectively. I don't have any idea if they were pushing too hard or if they just lost the wx lottery but I don't think the design is the main issue.

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Old 05-08-2010, 16:46   #127
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Just asking for a clarification....

Okay, I admit I don't have a dog in this fight.....since while I've sailed 10,000's of miles offshore in monohull's, my only multihull experiences were 35 years ago, on 16' Hobies......

So, I have little to contribute, except for a question or two....

Quote:
Originally Posted by Eleven View Post
this wind would have laid over many mono's.
Yeah, a sudden 60+ kt. gust would've laid-over some mono's....although certainly not rolled any real blue-water mono.....
But, it's the next line that I wish to inquire about.....



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In those conditions hatches would have been open for ventilation. Boat sinks.
Salvage chances 'Nil', survival chances adrift mid-ocean in a life raft - poor.
I'm assuming this is meant tongue-in-cheek??
a) Since in all my 40+ years of sailing mono's offshore, I've never sailed offshore with hatches open, and never seen, or heard of, anyone sailing in / near squals with hatches open......
b) And, while as I wrote above I have no offshore multihull experience, but I'm not sure that I'd find hanging onto the bottom of an up-turned hull to be more "survivalable" that being inside a decent offshore liferaft....

Again, I'm NOT trying to say mono's are safer, etc.....rather I'm just seeing if my assumptions regarding the above comments by "Eleven" are correct.....they were meant as humorous, and tongue-in-cheek????

Thanks....


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Old 05-08-2010, 17:15   #128
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a) Since in all my 40+ years of sailing mono's offshore, I've never sailed offshore with hatches open, and never seen, or heard of, anyone sailing in / near squals with hatches open......
I agree that it is a very bad idea to sail a boat in such a way that there is a danger of downfloading in a knock down. However, it happens. The very first person who I knew who died at sea did it by making just this mistake. The crew were racing in an overnight race in relatively calm conditions and took a wave in through the fore hatch that ultimately lead to the boat sinking and the men spending a night and day in the water. Two died of exposure one of whom lived a block down the street and was the father of my babysitter. And, of course, we've linked the Concordia several times now. Lacking a reasonably complete database of losses at sea and their causes we have to rely on our limited experiences. However, one should be cautious about drawing conclusions from small samples.

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Old 05-08-2010, 19:48   #129
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--- I'm not sure that I'd find hanging onto the bottom of an up-turned hull to be more "survivalable" that being inside a decent offshore liferaft....
I agree entirely. Which is why capsize victims who have survived periods of time before rescue did so by staying inside the capsized multihull where their supplies are (food, water, tools, etc.). Much more comfortable than a life raft I dare say. Being outside the boat is to keep a lookout for rescue craft, etc.
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Old 05-08-2010, 20:57   #130
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[QUOTE=ka4wja;497665]
I'm assuming this is meant tongue-in-cheek??
a) Since in all my 40+ years of sailing mono's offshore, I've never sailed offshore with hatches open, and never seen, or heard of, anyone sailing in / near squals with hatches open...... /QUOTE]

Ka4wja…. I read that also and simply bit my tongue.

Sailing offshore, Deck hatches are never left open at night, we have individual fans above every sleeping berth, supplied by dorade vents and in any unsettled weather, the main companion hatch is closed up along with all hatches.

In storm conditions the vents have watertight plates screwed in from inside


I think it may be multi owners who believe those opening will never be awash and are more relaxed about it.

As far as living inside an upturned Cat…. If you managed to keep the water out it would not be too bad, but if water started coming in via the main door, I would imagine the mix of diesel and lube oil with the free surface effect of seawater and whatever else emptied into the mix would not be as pleasant as the salesman would have you believe.

In a well built and operated mono, if you kept the water out, you would eventually right yourself, clean up, effect repairs and move on just as Jessica recently did.
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Old 05-08-2010, 21:07   #131
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steps to take when a squall approaches

Quote:
Originally Posted by ka4wja View Post
O
a) Since in all my 40+ years of sailing mono's offshore, I've never sailed offshore with hatches open, and never seen, or heard of, anyone sailing in / near squals with hatches open......
Monohull:

1. Close hatches.
2. Reduce sail.
3. Don foulies.
4. Clip in.

Multihull:

1. Reduce sail.
2. Close hatches.
3. Don foulies.
4. Clip in.
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Old 05-08-2010, 21:20   #132
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[QUOTE=Pelagic;497779]
Quote:
Originally Posted by ka4wja View Post
---
As far as living inside an upturned Cat…. If you managed to keep the water out it would not be too bad, but if water started coming in via the main door, I would imagine the mix of diesel and lube oil with the free surface effect of seawater and whatever else emptied into the mix would not be as pleasant as the salesman would have you believe. ---
Pelagic - It's been so long since I read this I can't remember much, but I'm sure it would make for interesting reading.

By John Glennie:
The Spirit of Rose-Noelle: 119 Days Adrift, A Survival Story

I'm sure it wasn't a 4 star hotel, but I don't think they spent 4 months sitting on top of the overturned hull(s).
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Old 05-08-2010, 21:55   #133
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I agree entirely. Which is why capsize victims who have survived periods of time before rescue did so by staying inside the capsized multihull where their supplies are (food, water, tools, etc.). Much more comfortable than a life raft I dare say. Being outside the boat is to keep a lookout for rescue craft, etc.
Which is was apparently what they did as well. I look forward to hearing more of the personal accounts from the skipper and his mate.

Quote:
The P3 Orion arrived on scene about 11pm yesterday and found Anna capsized and inverted. However, the American skipper and his New Zealand crewman were safe, one still on board Anna, and one in an inflatable dinghy attached to the catamaran.
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Old 06-08-2010, 02:43   #134
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Strange that there are many more sinkings of powerboats annually than of either monohulls or mutihulls, but no one is going after those members who have switched to powerboats as being delusional. It's also just strange that one set of sailors is suggesting that another set of sailors is delusional about their boats. Is that a normal practice on this forum?

Last time we cruised, we were on a ketch, but now we own a 23' monohull and a 37' catamaran, each with only one mast, so we will have to remain firmly on the side of the sailors of anything with a hull, I suppose. Hope that doesn't make anyone feel slighted; just to be on the safe side, we'll assert that masts are optional. Perhaps because we sold our ketch we should now be jingoistic about "one stick good, two sticks bad?"

Anyway, to answer an earlier request, sort of: all of the following are monohulls, incidentally. Not that it has special significance, as each accident has its own causes -- and they are not all pilot error, nor are all of them explained (in a couple of cases, the boat just "started sinking"):
Man rescued from sinking sailboat - Charleston SC - The Post and Courier - postandcourier.com
http://www.mercurynews.com/breaking-news/ci_15151943
Bellevue man treated for hypothermia after his sailboat beached near Newport | OregonLive.com
Sailboat explodes into flames off Port Townsend | KOMO News - Breaking News, Sports, Traffic and Weather - Seattle, Washington | Local & Regional
Whale Lands on Sailboat; Sailboat Loses – IndyPosted
2 sailboat racers rescued after capsizing - SFGate
Tanit Yacht Freed from Pirates - UPDATED | YachtPals.com

Five rescued from sinking sailboat near Cape Lookout, N.C. | HamptonRoads.com | PilotOnline.com
Five Members of Aggie Crew Rescued; One Found Dead
Four missing during family sailing trip, Coast Guard says - Projo 7 to 7 News Blog | Rhode Island news | The Providence Journal
Five rescued from sinking sailboat near Cape Lookout, N.C. | HamptonRoads.com | PilotOnline.com
Coast Guard Removes Crew of Sinking Sailboat North of Morro Bay | Coast Guard News
Coast Guard Rescues 6 People From Sinking Sailboat | Coast Guard News
Old Nabble - Rhodes 22 - 1 dead, 2 rescued from sinking sailboat off NJ

I tried to retrieve boating accident data from the USCG site where the summaries are kept, but they seem to not break it down by type of sailboat.
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Old 06-08-2010, 06:10   #135
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John, I would think that a sudden 60 knot gust would lay over all performance monohulls carrying full sail (and we are speaking of a performance cat here, so we should compare apples with apples). I agree, however, that they shouldn't sink unless they lost the rig (a real possibility) which then holed the hull before it could be jettisoned. Regardless, I am not sure how that helps us here.

Like many of the other posters, I have owned and sailed many monohulls and still love them - although for my current needs, a cat is vastly superior. Do I think that both perform in exactly the same way? Of course not. Obviously the risk of capsize and remaining capsized is infinitely greater in a multihull than in a ballasted monohull (some offshore racing monos - ie, the early Open 60's, aside); on the other hand, the risk of sinking in a properly engineered multi (as these boats were) is also infinitely less than a ballasted monohull. As to the relative risks, most insurers do not consider a properly designed/built/maintained multi to be any greater risk than a comparable monohull.

Where does this take us? Again, I suggest that this 'multi/mono debate' is outside of the scope of this discussion: it is hardly helpful in the mulithull section of the site, when attempting to analyze what happened and to avoid similar events, to in effect suggest: they should have had (and all of you should have) monohulls. And really, this is the inference when one interposes monohulls into the discussion.

Is one safer on an inverted multi? Again, irrelevant except to the extent that the crew of the Anna were rescued from the bridgedeck of their inverted cat (and no doubt, an inverted cat is much easier to spot from above). Many of us also carry liferafts; my boat (and some others) have ubolts installed under the bridgedeck to lash down the inflated liferaft, which will then be much more stable than a liferaft on the open seas (afterall, what is the worst that can happen - the multi flips back upright - lol). Again, however, I suggest that this is outside of the scope of this discussion.

While the precise cause/s for the capsize of the Anna will never be known (lets face it, even with the equivalent of a digital flight recorder that would be difficult), we can draw some reasonable conclusions and make some reasonable suggestions for minimizing that risk. Automatic sheet release mechanisms, as has already been suggested, would certainly have helped.

I am still convinced that a proper line clutch - one that slips (or more to the point, disengages) when a certain pressure is reached, would be ideal. Yes, there would be some false postives - instances where the sheets released in a gust insufficient to cause capsize. But surely that would be: 1. a good sign that one needs to reef NOW; and 2. nothing more than an inconvenience, if the boom were fitted with a boom brake, or a reverse jibe preventer.

Another possibility I have been thinking of is a line stopper which is, in effect, mounted on a small sled on a track. The sled is held in postion by a strong spring with adjustable tension. If the sled moves a predetermined amount (which not only could, but should be a very short distance), the release lever contacts a fixed bar, or pin and the sheet is released.

Again, any thoughts?

Brad
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