Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 07-11-2015, 20:01   #481
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Capsize Prevention Devices

Quote:
Originally Posted by Pelagic View Post
Seems to me a designed weak link or automatic trip in the mainsail at a specific heel would be the precautionary solution for a cruising multi and should be the focus of this thread.
..or another subject thread
__________________

__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Old 07-11-2015, 20:14   #482
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Ganovelli anti-capsize devices

Quote:
Originally Posted by Aussiesuede View Post
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.

Wonder if its some of those type devices utilized in these Ganovelli devices?
Ganovelli Concept - Accueil

Capsize Prevention Devices - Page 2 - Boat Design Forums
__________________

__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Old 07-11-2015, 20:27   #483
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Genoa Sheet Line Release

Quote:
Originally Posted by Eleven View Post
The downside is the genoa is huge, but a tripping device (I like the idea of a self relieving winch) would be very effective in saving the boat in a side gust without crew intervention. The main is more of a problem when running before but it is relatively small.

Quote:
Originally Posted by brian eiland View Post
Interesting how the sheet (line) seems to be 'captured' by that secondary winch in addition to the primary one,...so not all is totally lost on the headsail's re-sheeting .
Inspect time frame 1:08-1:09
__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Old 07-11-2015, 20:55   #484
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Genoa sheet line release

Quote:
Originally Posted by Joli View Post
Have you ever seen a highly loaded sheet (maybe 8~12 tons on an Atlantic 57?) running free when the pawls strip? Are you sure you want that on your boat?

We are very, very, very cautious around sheets, winches and the triangle of death when loaded up. I would think long and hard about an emergency release.
Reference link
Genoa Sheet Line Release
__________________
beiland is offline   Reply With Quote
Old 07-11-2015, 22:41   #485
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2007
Location: Santa Cruz
Boat: Boatless Again
Posts: 4,334
Re: Large Cat Flipped off Niue

Quote:
Originally Posted by beiland View Post
I know this goes back awhile in your memory banks, but do you recall how much of a shift in direction that 'big wind' came from compared to the reaching direction you had been sailing in??
Seems to me that the windshift was over 100 degrees, because we changed tacks. It was part of a frontal passage, but came suddenly during the squall, along with a lot of rain. I remember that the boat in front of us was War Baby, a C&C 61 out of Bermuda that belonged to Herb's boss.
__________________
donradcliffe is online now   Reply With Quote
Old 07-11-2015, 23:48   #486
Moderator
 
JPA Cate's Avatar

Join Date: Nov 2011
Location: aboard, cruising in Australia
Boat: Sayer 46' Solent rig sloop
Posts: 10,712
Re: Large Cat Flipped off Niue

Following the capsize of the "Anna", evanstarzinger posted an idea for a "fuse", a lashing of the clew of the mains'l to the outhaul, that would break if "x" lbs. of force were applied. Seemed like a good idea to me, rather lose a sail than a boat. Of course, you might have to contact an engineer to learn the right breaking strength, unless that sort of calculation is part of your skill set.

Ann
__________________
Ann, with Jim, aboard US s/v Insatiable II, in Oz, very long term cruisers
JPA Cate is online now   Reply With Quote
Old 08-11-2015, 00:25   #487
Registered User
 
UNCIVILIZED's Avatar

Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
Re: Large Cat Flipped off Niue

Quote:
Originally Posted by Ann T. Cate View Post
Following the capsize of the "Anna", evanstarzinger posted an idea for a "fuse", a lashing of the clew of the mains'l to the outhaul, that would break if "x" lbs. of force were applied. Seemed like a good idea to me, rather lose a sail than a boat. Of course, you might have to contact an engineer to learn the right breaking strength, unless that sort of calculation is part of your skill set.

Ann
Ann, it's pretty simple really. You can go to either the http://www.harken.com/Calculators/ website, or Betn & Evans page http://bethandevans.com/calculators.htm & both have calculators which show you/let you figure the sheet loading on sail type X, at wind speed Y. And then you'd build a "fuse" out of line type Z, which when tied in knot A or B, or spliced into variant C, breaks at the pre-determined load that you want.
And, poof, you have a fuse.

Although on a fully battened mainsail, that would make one holy hell of a mess of it, when it slammed into the shrouds @ Warp 9, untethered. Might even bring the rig down, given the shaking, flogging, & what not that it'd set up in high winds.
That, & it's tough to get a FB main depowered quickly, simply due to the battens.

The fuse thing is done all the time on some of the various types of Code Sails (& some others), on their tack fittings (& rare occassions, elsewhere), on the bigger race boats. So that if the sail will blow out with a 3 ton wind load on it, you put 2 or 3 (shorty) fuses onto it's tack, which blow before the sail actually gets to it's true tack pendant being under load.
Setting them to blow at say 1.5t, & 2t, so that when they start blowing, you know that it's time to furl up that sail, & save it for later... When there's less wind.

The basic math for wind loading on a sail is; SA (in sqft) x wind speed (in knots) squared x 0.00432 = Sheet Load in Pounds
It varies a bit from sail type to sail type, with mainsails typically being higher than that formula would suggest, but the websites will school ya.
Old trick from the racing world.
__________________
UNCIVILIZED is offline   Reply With Quote
Old 08-11-2015, 10:56   #488
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Re: Capsize Prevention Devices

Quote:
Originally Posted by beiland View Post
..or another subject thread
Ah yes, there have been several other such subject threads:
1) Anti-Capsize Devices

2) Automatic sheet release (older thread)
__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Old 08-11-2015, 11:57   #489
Sponsoring Vendor
 
Schooner Chandlery's Avatar

Community Sponsor

Join Date: Jan 2007
Location: home port Washington DC
Boat: SS Crocker design #131
Posts: 977
Re: Large Cat Flipped off Niue

Quote:
Originally Posted by UNCIVILIZED View Post
Ann, it's pretty simple really. You can go to either the Harken website, or Betn & Evans page Calculators & both have calculators which show you/let you figure the sheet loading on sail type X, at wind speed Y. And then you'd build a "fuse" out of line type Z, which when tied in knot A or B, or spliced into variant C, breaks at the pre-determined load that you want.
And, poof, you have a fuse.

Although on a fully battened mainsail, that would make one holy hell of a mess of it, when it slammed into the shrouds @ Warp 9, untethered. Might even bring the rig down, given the shaking, flogging, & what not that it'd set up in high winds.
That, & it's tough to get a FB main depowered quickly, simply due to the battens.

The fuse thing is done all the time on some of the various types of Code Sails (& some others), on their tack fittings (& rare occassions, elsewhere), on the bigger race boats. So that if the sail will blow out with a 3 ton wind load on it, you put 2 or 3 (shorty) fuses onto it's tack, which blow before the sail actually gets to it's true tack pendant being under load.
Setting them to blow at say 1.5t, & 2t, so that when they start blowing, you know that it's time to furl up that sail, & save it for later... When there's less wind.

The basic math for wind loading on a sail is; SA (in sqft) x wind speed (in knots) squared x 0.00432 = Sheet Load in Pounds
It varies a bit from sail type to sail type, with mainsails typically being higher than that formula would suggest, but the websites will school ya.
Old trick from the racing world.
A fuse is really the right kind of idea. In the days of real canvas (pre-Dacron and more high tech fabrics), sails just blew out, providing their own fuse of sorts.

Like the (less strong) pennant we use at the tack of our hanked on headsails and our flying jib or fisherman, I'd think others do the same. Maybe not so.
__________________
"The only noble thing a man can do with money is to build a schooner." Robert Louis Stevenson

Schooner Chandlery is offline   Reply With Quote
Old 08-11-2015, 20:16   #490
Registered User
 
UNCIVILIZED's Avatar

Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
Re: Large Cat Flipped off Niue

Quote:
Originally Posted by Schooner Chandlery View Post
A fuse is really the right kind of idea. In the days of real canvas (pre-Dacron and more high tech fabrics), sails just blew out, providing their own fuse of sorts.

Like the (less strong) pennant we use at the tack of our hanked on headsails and our flying jib or fisherman, I'd think others do the same. Maybe not so.
You can, theoretically, put a fuse into the sheet. Or use two sheets, one set to break at a lower, pre-set, level. And the BANG that they'll make when breaking, should get your attention.
The catch being, choosing at what breaking strength to make/set them. As, in an emergency, you don't want to be messing around with lines which may or may not hold when you need them to.

But... such is theor on my part, not having tried it out in the real world. And I know that doing so would be tricky, given the often multi-ton loads on some lines.
__________________
UNCIVILIZED is offline   Reply With Quote
Old 08-11-2015, 21:55   #491
Sponsoring Vendor
 
Schooner Chandlery's Avatar

Community Sponsor

Join Date: Jan 2007
Location: home port Washington DC
Boat: SS Crocker design #131
Posts: 977
Re: Large Cat Flipped off Niue

Quote:
Originally Posted by UNCIVILIZED View Post
You can, theoretically, put a fuse into the sheet. Or use two sheets, one set to break at a lower, pre-set, level. And the BANG that they'll make when breaking, should get your attention.
The catch being, choosing at what breaking strength to make/set them. As, in an emergency, you don't want to be messing around with lines which may or may not hold when you need them to.

But... such is theor on my part, not having tried it out in the real world. And I know that doing so would be tricky, given the often multi-ton loads on some lines.
Yes, it would be a bit much.
__________________
"The only noble thing a man can do with money is to build a schooner." Robert Louis Stevenson

Schooner Chandlery is offline   Reply With Quote
Old 08-11-2015, 22:49   #492
cruiser

Join Date: Aug 2014
Posts: 506
Re: Large Cat Flipped off Niue

All this talk of fuse's makes my blood run cold.

Ever watched what happens when the pawls strip on an overloaded winch?

Ever heard of the triangle of death?

Whatever system of release is chosen there has to be some control or someone is almost certainly going to pay with their life.

The maxi tri sheet release demonstration showed the sheets set up on two
winches with limited release for control.

Blowing a weak link is just silly inexperienced talk at best, deadly at worst .
__________________
Seaslug Caravan is offline   Reply With Quote
Old 08-11-2015, 23:05   #493
Sponsoring Vendor
 
Schooner Chandlery's Avatar

Community Sponsor

Join Date: Jan 2007
Location: home port Washington DC
Boat: SS Crocker design #131
Posts: 977
Re: Large Cat Flipped off Niue

Quote:
Originally Posted by Seaslug Caravan View Post
All this talk of fuse's makes my blood run cold.

Blowing a weak link is just silly inexperienced talk at best, deadly at worst .
Have you heard of naval architect John Leather? A rather famous fellow Link and certainly not silly nor inexperienced. It was from him that I learned a bit about the whole matter of canvas failing, sails failing, and using modern sailcloth one needs to think of ways to protect the rig and vessel from the winds since the sailcloth isn't going to provide the fuse it used to do. Sadly, John passed on in 2006. A great man with deep knowledge. I don't know the techniques that John and other experienced naval architects would recommend but I suspect there are some very experienced folks here on CF who do.

I won't belittle something just because I don't know how to take it on myself and I hope you're not the sort who does that either. Big forces are deadly forces, yes, but that doesn't mean there isn't a need for dealing with them and that there aren't ways of dealing with them.
__________________
"The only noble thing a man can do with money is to build a schooner." Robert Louis Stevenson

Schooner Chandlery is offline   Reply With Quote
Old 09-11-2015, 05:23   #494
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Sheet Release Video

Quote:
Originally Posted by Seaslug Caravan View Post
All this talk of fuse's makes my blood run cold.

Ever watched what happens when the pawls strip on an overloaded winch?

Ever heard of the triangle of death?

Whatever system of release is chosen there has to be some control or someone is almost certainly going to pay with their life.

The maxi tri sheet release demonstration showed the sheets set up on two winches with limited release for control.
I assume you are talking about the video demonstration i posted back on posting #483

I might add that the closer inspection is also shown at time frame 1:49
__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Old 05-11-2016, 06:35   #495
Marine Service Provider
 
beiland's Avatar

Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,142
Re: Atlantic 55 Comments

Quote:
Originally Posted by Dragon701 View Post
While my family and I spent a year sailing our Atlantic 55 over 8500 miles, I consider myself a beginner on it and catamarans in general. I have sailed Hobies and charter cats a fair bit, but nothing offshore before this one. I have, however, sailed over 100,000 miles in mono-hulls (first Atlantic crossing in 1969).

For me, the old "saw" about setting your sails to the lowest expected wind speed in a mono-hull and to the highest expected wind speed in a catamaran says a lot about the differences in managing the boats. Given that the highest "expected" wind speed is both a guess (or, hopefully, a sound judgment) and without practical limit on the upside, setting the right sails was, for me, more of an uncertainty on a cat than on my mono-hulls. This is another way of saying that, for me, a mono-hull was more forgiving of an error in picking the right sail combination.

A person could increase his or her margin of error for a wind driven capsize (the “forgivingness”) on any catamaran by decreasing the size of its rig and vice versa. Obviously, this is a true statement for a mono-hull too, but, in my opinion, it is a more powerful lever on a catamaran.

On our trip from the Bras d'Or Lakes in Canada direct to Bermuda in September 2009, we chose to leave on the back of a front. Our winds were a steady 30 knots, which meant lulls to 20 and gusts to 40. We were reaching with double reefed main, staysail and the windward board down. The seas were not unusually big for these conditions, but very confused as we came out around Sable Island. The water is shallow (in the macro sense -- 75' to 250') causing the currents to swirl around. I felt very comfortable with this rig. Had the wind increased to over 60 knots in one of the squalls that we experienced, the boat would have handled it fine. I would have headed off some more, eased the main sheet, pulled another reef (which we could do just fine off the wind) and rolled in some staysail. I wouldn't have wanted a single reefed main and staysail up.

That said, I don't believe that Anna was over canvassed beating with one reef and the staysail up in 12 to 20 knots of apparent wind with squalls around (as I interpret his account). Nor do I find it inappropriate that they were on autopilot and in the wheel house.

It is so easy to be the Monday morning quarterback -- I really hesitate. This is just one point of view:

1) We wouldn't have left in these conditions unless for some odd reason we had to. My wife is an atmospheric scientist so we have excellent weather information and analysis. She (we) reviewed the data that we would have had before this trip and I base my comment on this review. Of course, I realize that it is easy for me to make this judgment here and now. This situation was different from the front we left Canada on. Our situation then was more "stable" in a way and we knew we were in for a lot of wind, so we were ready for it. Even with the much lower general wind speeds, I would describe this situation as more "unstable" or perhaps uncertain than ours was.

2) It is impossible to say how we would have reacted to the sky conditions at the time, but assuming that they were same as they had been for the last 24 hours, I might have left the boat in single reef/staysail/autopilot. The Anna folks mentioned that they were "wary." Maybe, we would have done something different. Maybe I would have been in the cockpit, maybe not. Maybe we would have been hand steering. Maybe we would have used the radar to avoid the core of the squall. Maybe we ... well, this is just too speculative for me to form an opinion.

So, assuming that we had stayed set up the way they were:

3) We focus on TRUE wind speed on our catamaran, not apparent, and set our sails based on this and what we expect it to be. This isn't to say that we are unaware of the effect of our boat speed on the wind, which for us has been eye popping with the A55 versus any mono-hull that I have sailed. In the Anna case, they were beating so the true wind was less than the apparent. When the wind gusted and went abeam, however, in our A55 anyway, the boat would have accelerated and the true wind would have been well aft of the beam. In our boat, the true wind would have read higher than the apparent wind, so they were probably already seeing higher winds than the 30 knots that made them jump into the cockpit.

4) Given the above, my first move, before I even left the pilot house, would have been to knock the autopilot down 30 to 40 degrees (three or four pushes of a button). In these specific circumstances with our boat -- e.g. with my sails flattened for beating but the wind coming abeam and increasing -- I would not head up into a squall; I would bear away.

5) Then, I would have eased the main sheet.

6) If was not alone and depending on how the boat was riding, I would take the helm (if my wife was with me, she would have taken it) and the other person would then start cleaning up -- first a reef (or two), then shorten the staysail.

I really love boats, any boats -- power, mono, ship, cats, sail, oars, ice, kayak -- they all have something to offer. The Atlantic 55 was a terrific choice for our family. My wife and I (we sailed about 58,000 miles together during a wandering circumnavigation, plus some, in the early 1980s) are converts to catamarans for our cruising lifestyle. We love the stable platform. In the case of the A55, we love the speed, the space, the forward cockpit, and the pilot house/living room among many other things.

There are characteristics which we don't like too: the A55 has appendages to catch things on (two dagger boards, two sail drives and two rudders). We caught three fishing nets/lines during our one year. I realize that some mono-hulls do too, but they only have one hull to worry about and we have two .

Would I go around Cape Horn in a catamaran (as we did in 1981)? Yes. Would I go into the ice with one (in 1984, we went into ice at over 80 degrees north)? I am not so sure about that -- I would be worried about ice jamming between the hulls.

I have a lot to learn about multi-hulls, but for us, for our long-distance sailing, we won't be going back to a monohull. The Anna Story is a wonderful reminder for me; something to keep me on edge if I ever become complacent.

I am so happy that they were rescued safely and in such a short time. I have spent almost as much time thinking about what they did after they flipped as I have about the cause of it. Lots of lessons learned there too.

Sorry about the long post. Blame Evans and Tom for drawing me in -- I have found their deep experience and thoughtful comments fascinating to read.
I just found this posting by Dragon, and thought it needed to be repeated. A very thoughtful analysis and experience.

I referenced it in another forum discussion dealing with the amount of sail to be set for certain existing conditions, AND contemplation of what might be coming soon. We often choose to undercanvas for safety reasons, and in those situations, adoption of a motor-sailing attitude might be appropriate.
__________________

__________________
Brian Eiland
distinctive exploration yachts
beiland is offline   Reply With Quote
Reply

Tags
Niue

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Access to Catamaran's Water-Tight Compartments when Capsized schoonerdog Multihull Sailboats 34 13-08-2011 16:36
Go Large, Go Now Starbuck Powered Boats 0 12-06-2009 18:42
This Is Really an Interesting Read ! Beveridge Reef and Niue Trim50 Off Topic Forum 6 01-11-2008 13:52
Large Sizes Moog General Sailing Forum 2 07-01-2007 23:23
Sea Chase Cat, or similar large cat...? CSY Man Multihull Sailboats 1 08-11-2004 10:25



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 23:59.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.