Multihulls - Heavy Weather (Passive) Handling

[jglauds]

Hi:

My copy of DDDB, picked up in a boat swap in Nuku Hiva, Marquesas (thanks whomever!) was published in 1998 or so ...

There are 41 case studies of monos and sea anchors off the bow, 21 trimarans and sea anchors, 20 cats w/ sea anchor, 9 power boats with sea anchors, 19 monos with drogues off the stern, 10 tris and drogues, and 9 cats and drogues. Extensive discussion of common findings etc. Can't comment on the Jordan Series drogue comment, but case studies cover many types of drogues and sea anchors.

I have a fully-rigged sea anchor as follows, ready for deployment in less than five minutes, and I plan to pre-attach the bow bridle before my major Indian Ocean crossings, running it back to the helm station, so all I need to do is deploy the balance of the rig in less than 1 minute from the helm station.

One of the things I've heard time and again is that the simple act of deployment is the most dangerous part of the exercise, and that the decision to go from "offense" to "defense" is the most important decision you make as a skipper.

I have a 44' cat, Fountaine-Pajot Orana. Pre-rigged, I have 2x90' bridles of 3/4" double braid nylon, each end terminated in a thimbled splice, connected by a 12mm x 70mm s/s ring -- said ring rated at about 11,250 SWL.

The bridle is attached to a 45' length of 3/8" BBB chain using a 3/8" Hi-Mod S/S shackle, rated at 8,360lbs minimum breaking load.

The chain is pre-attached to a 300' length of 3/4" 3-strand nylon tether, again using a 3/8" Hi-Mod S/S shackle.

The tether is attached to a 18' Para-Tech Sea Anchor, using a Para-Tech supplied oversized s/s shackle and a massive s/s swivel shackle.

I will use a 24" fender ball to serve as the primary float for the parachute -- it's essential that the parachute never be permitted to hang straight down, so the Para-Tech rig comes pre-equipped with a length of nylon to which one attaches a float buoy.

The overall length if the tether is thus 90' + 40' + 300' = 430', about the minimum recommended 10x length of my boat. It's important to have the parachute synched up to the wave period, so that the boat is at a wave peak when the parachute is at a wave peak, and trough = trough. It may be that I'll need a longer tether for seas which are further apart than 400' or so, which is a distinct possibility.

Thus, I have an additional 210' 5/8" nylon rode, with thimbles spliced into each end and appropriate shackles if sea conditions are such that I need a longer rode.

One of the major issues on these rigs is chafe, and we installed dedicated cleats at the very tips of our two bows, with backing plates, to avoid rope-on-boat chafe, and I also carry thick diameter reinforced plumbing hose to deploy if necessary.

I stress the following: THIS IS ALL BOOK KNOWLEDGE -- I have NO practical experience in deploying or using these storm management strategies.

I will say that two areas required significant research, and I'm still not 100% sure I've got things right. First, the entire rig will only be as strong as its weakest link ... the stresses can be enormous, and I spent a fair amount of time trying to synch up the shackle strength to the rope and chain strength. I think I have it mostly right. It turns out that manufacturers use several metrics, including:

• WLL, the apparently preferred metric by standard-setting agencies -- Working Load Limit;
• SWL, the Safe Working Limit, cited by many marine stores, etc.; and,
• MBL, the minimum breaking load, also cited by many marine stores.

I had to mix-and-match a bit as I sized the rig, by in short, I stayed away from galvanized shackles, since they are not strong enough for the diameter.

The second area of uncertainty was/is the appropriate length of chain between the bridle and the rode ... it's essential that the parachute stay in the water, and Para-Tech recommends the chain, which also serves a dampening role as a result of its concatenary sag, be no more than 20 percent of the length of the rode. Some have suggested longer chain ...

That's it folks -- a novice's effort to be prepared ... lots of this is available for free at the Para-Tech website ... several comprehensive downloadable PDFs ...

Comments/reactions welcome ...

/jon

[mikereed100]

Originally Posted by Palarran

.
As I said before, I'm choosing to follow what professionals do, not casual cruisers.

Sorry, but I can't resist

To which catergory do Walter Greene;
"For a boat that sails across the Atlantic and stuff like that I'd recommend a sea anchor..."

or the Casanovas belong?
Amazon.com: The Parachute Anchoring System and other tactics: Cape Horn Proven Heavy Weather Sailing for Multihulls: John Casanova, Joan Casanova, Victor Shane, Daniel C. Shewmon, Gregory MacMillan: Books

Mike

[AllezCat]

Originally Posted by jglauds

The overall length if the tether is thus 90' + 40' + 300' = 430', about the minimum recommended 10x length of my boat. It's important to have the parachute synched up to the wave period, so that the boat is at a wave peak when the parachute is at a wave peak, and trough = trough. It may be that I'll need a longer tether for seas which are further apart than 400' or so, which is a distinct possibility.

/jon

Sounds like a well researched and appropriate amount of rode, anti-chafing and bridle, etc.
I researched all that stuff very heavily on my first boat - not intimately familiar with the recommended specs again, as yet. But I have the minimum length of rode.
I am not a big fan though of trying to sync with the waves - impossible in the dark (half the time) and it should/will stay submerged....
just my thoughts.

[Palarran]

Originally Posted by mikereed100

Sorry, but I can't resist

To which catergory do Walter Greene;
"For a boat that sails across the Atlantic and stuff like that I'd recommend a sea anchor..."

or the Casanovas belong?
Amazon.com: The Parachute Anchoring System and other tactics: Cape Horn Proven Heavy Weather Sailing for Multihulls: John Casanova, Joan Casanova, Victor Shane, Daniel C. Shewmon, Gregory MacMillan: Books

Mike

Resist what? Anyone can write a book.

As far as I can tell - amature. I don't find anything else on Casanova. It's also another book written almost 20 years ago.

Professionals are just that - they are not some husband and wife team who are doing a single circumnavagition. I've seen a half dozen Leopard catamarans delivered from South Africa into St. Martin over the last year. Three by the same crew. These guys don't use sea anchors. My friend has done 15 Atlantic and two pacific's, no sea anchors. These are professionals, I'll follow their advice.

[tsmwebb]

Originally Posted by Palarran

...
Professionals are just that - they are not some husband and wife team who are doing a single circumnavagition. ... These are professionals, I'll follow their advice.

Ah, but here I suspect that most of us even if we have professional credentials and substantial sea time are husband and wife teams when we cruise. What is appropriate for a strong skilled delivery team might not work well with the typically asymmetrical skills and strengths of the mom and pop crew. Sailors when they are working the boat are athletes. Top level sailors are no more like average sailors than top level track and field stars are like weekend runners. When things get stressful the pro crew may well have the endurance, strength and skills to carry on safely longer than the mom 'n pop team. Gear and methodology should be matched to the boat and the crew and the expected service. IMO, choosing what the pros use just because they're pros can get a person into a lot of trouble in many endeavors.

Tom.

[Palarran]

Well, maybe I didn't clearly describe the delivery crews I've seen pulling up to the Moorings docks. I wouldn't call them finely tuned athletic machines. They usually are more concerned where they can get a pack of smokes, a six pack of beer, and maybe a piece of fresh fruit. They hop off after 35 days nonstop, get a good buzz on, load the boat up with about 2000 lbs of supplies from Budget Marine, and take back off for the BVI's. Maybe a trip to the whore house. But the turnaround time is a day, maybe two.

So, if I'm a beginning runner, and I'm going to do marathon's, I would look at the person who knows how to get all the way to the finish line, not a sprinter (can racer) or a pole vaulter (monohull sailor). As far as credentials, to me they don't make you a professional, they make you a capable candidate. Having a job and getting paid makes you a professional.

If the strengths of the typical husband and wife team are not strong enough to utilize the the skills required of a professional, then maybe they should hire one. Age would be a factor also. At some point, you are going to fall physically apart. And if that happens offshore, you force a rescue that shouldn't have happened. There are non-stop stories about sailors who in their younger days sailed the world and then, later in age decide to give it a go again. They get in over their head and are lost.

As for choosing to use what pro's use - that has to be one of the most common routes out there for almost everything. Turn on a tv and watch a commercial. Would it be better to use what the amateurs use? Come on.

[Palarran]

Originally Posted by AllezCat

he was talking about a chute style drogue versus a series drogue( many little chutes).
There was a better drogue available some years ago that solved all problems.
It was a solid cone shaped unit. And had venturi "things" on the side that opened at speed. So, in theory it would slow the boat to a reasonable cruising speed(say 7 knots) but then on steeper waves if it began to surf the venturi things would open up creating more resistance and maintaining the slower speed.
But was rapidly off the market - so maybe not so good in practice???

Is this the one you where thinking about?
A STORM Drogue for Extrreme Conditions

[tsmwebb]

Originally Posted by Palarran

Well, maybe I didn't clearly describe the delivery crews I've seen pulling up to the Moorings docks. I wouldn't call them finely tuned athletic machines. They usually are more concerned where they can get a pack of smokes, ...

Sometimes it is hard to tell just by looking at a person. This guy doesn't look like much and is said to smoke like a chimney and yet is an elite athlete.

So, if I'm a beginning runner, and I'm going to do marathon's, I would look at the person who knows how to get all the way to the finish line, not a sprinter (can racer) or a pole vaulter (monohull sailor). ...

Interesting. If I were going to run a marathon I would seek out people of similar talents who had just completed one or two. Almost by definition they would be amateurs. Sadly, the analogy breaks down a bit here because very heavy weather is rare on most cruising or delivery routes in season. Pros and amateurs alike can sail for years and hundreds of thousands of miles and with luck and care never experience a storm at sea. I happen to carry a rather nice sea anchor and a nice drogue and I've never used either in dangerous weather and will be happy if I retire them of old age never used. I feel that way about lots of safety equipment -- my lifelines have yet to keep me from falling overboard but I replace them periodically anyway, my flares get disposed of unused on a regular basis, my epirb gets new batteries and my life raft gets repacked and with luck none of them will ever be needed. But if I want to know what to expect in the unfortunate event that I need any of those things I seek out the experiences of people who have needed them. A pro who has never needed to set a sea anchor or drogue may well believe that they are not necessary equipment and may be correct in a statistical way but his advise on how to used them in the rare event that they are useful is not going to be as interesting to me as the advise of someone who has used the equipment.

If the strengths of the typical husband and wife team are not strong enough to utilize the the skills required of a professional, then maybe they should hire one....

I think one of the nice things about cruising is that there are lots of way to go about it. I agree that if a crew doesn't have the abilities to navigate safely they should not sail. However, professionals need to meet schedules largely with the equipment they are given. A cruising couple can choose their time, their equipment and their pace which may, if needed, make up for a some deficits in talent and strength.

Tom.

[GnarlyMon]

Seems to me that the Richard Charrington incident doesn't really tell the whole story of whether a sea anchor is effective or not. Firstly, they waited and didn't go from offense to defense quick enough. They disregarded a dropping barometer that had an alarm going off and lastly and most important......."They’re able to tie the line on the port bow finally, but can’t get a line over to the starboard bow. They’re in danger of losing it overboard. So Jean-Claude wraps it on the beam near the headstay, the wire between the bows that holds up the mast. This puts the boat at an angle to the sea anchor, dangling by its port bow, and this is why the boat will later flip over in the night."

Again, you're going to hear the comprehensive reports when something goes wrong and not hear anything when the system is deployed correctly and succesfully.

Even having waited to deploy, I would love to know what the outcome would have been if the starboard line would have been tied correctly and the boat not riding at an angle to oncoming seas. Surely, I don't know but I'm venturing to say it would have been just another one of the "successful riding out of the storm" entries in the DDD database.

[mikereed100]

Originally Posted by Palarran

Resist what? Anyone can write a book.

As far as I can tell - amature. I don't find anything else on Casanova. It's also another book written almost 20 years ago.

Professionals are just that - they are not some husband and wife team who are doing a single circumnavagition. I've seen a half dozen Leopard catamarans delivered from South Africa into St. Martin over the last year. Three by the same crew. These guys don't use sea anchors. My friend has done 15 Atlantic and two pacific's, no sea anchors. These are professionals, I'll follow their advice.

What I was getting at is that Walter Greene, a well known multihull designer and experienced ocean racer, a true "professional" in every sense of the word, recommends a parachute anchor on offshore voyages.

The Casanovas, while technically "amateur" since they weren't being paid, spent a lot of time sailing in the Southern Ocean on their 38' Horstman tri, deploying a parachute anchor to good effect at least 10 times.

Mike

[dochueb]

WARNING: Poster with NO experience here...

No boat, very minimal sailing experience. Dreaming. Doing a LOT of reading.

Storm Tactics (Lin & Larry Pardy) discuss at length the "slick" effect of a parachute sea anchor. (They talk about this with the keel of a mono mostly, but do report the sea anchor creating this slick with multihulls.)

The "slick" apparently causes waves to break ahead & aft of the boat, but not onto the deck.

Anyone have any experience with this? Does it do anything to improve the sea anchor's effectiveness in these situations?

Thx,

DH

[niel12]

I find this thread facinating and very informative ... Sure we older sailors should not take acception at the former statement about "youthfull sailor that after absence start again when he is older and seemingly less fit" or should we?

I think the type of passage determines the need for planing - a delivery skipper is doing a job and wants to finish safely and get back to his family while a cruising couple is diffrent ball game. Here planning for all eventualities iclude the most up to date electronic equipment like weather faxes etc etc which one can study a plan your actions. ie furl your mains, rig your storm sail. I think a cockpit drain is a necessary improvement to many cockpits, i saw that in St Francis 50.

I think planning your passage and leave nothing to chance is far better than doing nothing!

[sabray]

I love the idea of series drogue it transfers energy in a very distributed application. I ran a storm where a drogue would have been good instead we sailed or ran off. Good for us us as running is where we were going. Think this worked as we were not receiving energy from the waves or diminished energy. Had the waves gotten much steeper or period shorter we would have wanted a tie back to a prior wave. Then a drogue would have been a good answer. I think we were very on the edge of wanting a drogue. Not having deployed either anchor or drogue it is all a guess. We had full ability to steer. Perhaps a drogue would have limited that. In a multi hull the energy is going to be transmitted in an entirely different way. Perhaps a sea anchor would be a much preferred way. In a large surface heavy displacement boat a drogue seems like a nicer option. I think in reflecting upon that experience the boat I own would do better with a drogue.but oardey would disagree. We kept sailing in between prayers. When a 58 foot boat surfs down a wave you know you've gone sailing. The worse part was these rogue side waves that would broad side us. Hour after hour in darkness you played the helm resistance coming off a white cap and plunging down the side, then a unsequenced wave would slam full tilt abeam and the water would just engulf the helm. I just can't I,agine be bow into that **** with little helm control. I imagine the entire force of the hull and wave energy being thrown against the steering gear and rudder. one boat one storm with a longer period between waves I could see a sea anchor being a good choice. Especially if you didn't want to go the way the wave were inclined. There is just no good one answer.

[niel12]

That is a interesting view and yes there is no set pattern of action for a storm as each storm is unique. I might have a gimmick as one guy said, in the near future to make things a storm a little easier so keep watching!

[aking9999]

I am looking to sail a small cat from New Zealand to Australia, I would like to know when the best time to do this is, and also what would the requirements be for Cat One on the boat. I have done blue water sailing before.