Drogues or sea anchor or neither

[thinwater]

Originally Posted by a64pilot

Not trying to start any kind of bashing, but I can see how that a lightweight Cat in stupid high winds, coming off of a wave with the bow high, could lift out of the water, whereas from the stern it would seem to be much less likely.

Me either. Research case studies. To my knowledge, this specific failure has never happened. My suspicion is that by the time the wind gets that high, you are more or less, screwed no matter what you've done. Cats have flipped at anchor. Monos have sunk. Generally it was the eye of a >4 huricane, which you aren't likely to survive at sea.


How many cats could not survive a major wave break on the transom/cockpit? Monos have caved in a window and sunk. Keels have come off. Rudder tubes leak.

[Jim Cate]

With a para anchor off the bows on a cat, wouldn't the downforce from the 'chute prevent this sort of backflip?

IIRC, in the Queen's Birthday storm of '94, a cat called Ramtha survived hanging from a chute. They did suffer rudder damage from surging backwards (again IIRC) and eventually abandoned her. She was later recovered and still in pretty good shape (we were aboard a few months later and were surprised how OK she was). That storm sank a number of boats and had extreme sea states with winds <100 knots but still damn high.

Jim

[a64pilot]

I wasn’t trying to start any kind of bashing, just thinking maybe a JSD from the stern would be better than a chute off of the bow on a lightweight Cat.
Not saying one is better than the other, just that they are different, and what works for one, may not be the best plan for the other is all.

At anchor, my boat sails all over the place, it’s often bad enough so that it’s obnoxious. Our first sewing project was an anchor riding sail, however what seems to really tame the sailing at anchor is an additional line connected to the rode about 50’ in front of the boat and with your sheet winch tighten it up so that the boats bow is pulled to port. This stops all that sailing nonsense, and of course is what I think the Pardey’s did with their sea anchor, cause I assume my boat would sail around a sea anchor, a lot like it does a regular one.

[thinwater]

Originally Posted by a64pilot

I wasn’t trying to start any kind of bashing, just thinking maybe a JSD from the stern would be better than a chute off of the bow on a lightweight Cat.
Not saying one is better than the other, just that they are different, and what works for one, may not be the best plan for the other is all.

At anchor, my boat sails all over the place, it’s often bad enough so that it’s obnoxious. Our first sewing project was an anchor riding sail, however what seems to really tame the sailing at anchor is an additional line connected to the rode about 50’ in front of the boat and with your sheet winch tighten it up so that the boats bow is pulled to port. This stops all that sailing nonsense, and of course is what I think the Pardey’s did with their sea anchor, cause I assume my boat would sail around a sea anchor, a lot like it does a regular one.

Generally, cats with a bridle don't sail much.


The challenge with monos and sea anchors is that the sail becomes worse because you are moving backwards, if slowly.

[Palarran]

Originally Posted by JRKR

Hi, I have recently placed an order on a new catamaran and plan to do ocean sailing. I come from a mono hull background and was wondering if any Cat blue water sailors could offer advice on should I investigate drogues or sea anchors or just simply rely on ocean passage planning and a close check on weather patterns.

Wow, you probably got overwhelmed about 3 pages ago with the cat fight. There are about 100 threads on this subject that you might want to read. I did the same thing as you are when I purchased Palarran. IMO, and it's one that isn't shared here by many, there would be almost no chance that I'd ever deploy a sea anchor off the bow's of a catamaran in true STORM force conditions. I don't think the design of typical cats can withstand the force of breaking seas on their bridge decks. And, if the bridle or line snaps, the resulting immediate surge of the boat backwards will at best snap your rudders and at worst trip the boat over backwards. I've talked to many, REAL delivery skippers for Fountaine Pajot and Leopard (when they used to deliver via own hulls) and none of them had parachute sea anchors or drogues. They all said that they could build an effective drogue using lines on board, chain, fuel cans, and fenders. But none had actually done that.

Probably the best advise was to run with the storm until you run out of sea room, then turn into the waves and motor approximately 20 degrees off the wave train at about 3 knots until the storm passes. This is what I did on my first Atlantic crossing where the wind over a 72 hour period never when below 40 knots (nor above 50 luckily). It did blow me 3 days off course and to replay it, I should have made landfall in Madeira instead of the Azores.

Another thing to consider when reading stories and getting advice is the size of the boats that are involved. Your new 45' boat is going to behave differently than a 35' race boat or old Catalac. My 56' is going to also be different than yours. One drogue might be appropriate for you and two for me (though I don't have any). Using a drogue for emergency steering hasn't made sense to me as we have two rudders. I'd guess that there is at least a 90% chance of effectively solving a rudder failure on a cat.

Originally Posted by BigBeakie

Are you being specific in your statement about deploying from the bows in storm conditions? If so, it seems you have missed a major understanding on how Para-anchors are properly, ie effectively AND safely, deployed.

You do not deploy from the bow during a storm. Why would you do that? You should deploy from the cockpit with the rode lightly attached to stanchion bases down the length of one hull nearest the helm. You have set up the para-anchor before departing on your bluewater passage, as a matter of good seamanship.

On Youtube you can see Dr. Gavin La Seur in a Force 10 storm with his Para-anchor deployed and maybe you could read his book about Multihull Seamanship for specifics on many aspects of this topic. Highly recommended.

Have you actually read the drag device database? Refer Case S/C 8 in major storm in Gulf of Alaska on a Kelsall cat. S/C-8 Catamaran, Kelsall | Victor Shane's Drag Device Data Base

There is lots of good information out there from experienced bluewater skippers on storm survival that Mr. Google will lead you to.

Here is that video. I've seen it a lot of times and have to say that it cracks me up. Not really storm force conditions, maybe the wind clocked up to 60 knots for a bit but I doubt for long. It was pointed out to me once the difference in breaking waves. The only few that I see on this video are breaking behind the actual mass of the wave. If your in STORM force winds, the wave tops will break forward of the wave mass.

https://www.youtube.com/watch?v=iUQ5sdEzOko

Originally Posted by fxykty

Beam on actually may not be that bad even in moderate breaking seas, as cats (especially with daggerboards retracted, but even mini keels as they really don’t have much depth nor area really) will skid sideways. Larger seas, too scary to contemplate but abandoned cats that have been found later still floating and left to themselves had probably laid beam to the seas.

The real problem with cats heaving to in breaking seas is the risk of being driven backwards and tripping over the sterns. Unlike a monohull, even a relatively heavy catamaran has much more windage and much less inertia so that it won’t punch through a breaking wave when hove to.

Speed limiting drogue if you have room to leeward and not too extreme, or JSD or parachute anchor if not much room and/or survival conditions.

Nice post.

It's been a long time that sailors have had video cameras on their boats. Seldom for some reason do they actually post any video of their "incidents". My guess is that after reviewing it the "storm" doesn't actually look that bad - it probably wasn't. I can say that from personal experience and don't believe that it's just the camera flattening out the water. I actually think it's not as bad as our minds make it out to be at the time. Which is probably why so many boats are found still floating after abandonment.

Still, this is the best video I've seen of a catamaran in heavy weather - I know I'd be freaked out by it.

https://www.youtube.com/watch?v=hQ-svmgOxqw

[Palarran]

Sorry, I should add that at some point it was suggested that you could put either a drogue or JSD off the bows of a catamaran - don't do this - please. Not a good idea at all.

[Dan GB]

Originally Posted by JRKR

Hi, I have recently placed an order on a new catamaran and plan to do ocean sailing. I come from a mono hull background and was wondering if any Cat blue water sailors could offer advice on should I investigate drogues or sea anchors or just simply rely on ocean passage planning and a close check on weather patterns.

Just for what it's worth, I am in a similar position in that I have acquired a 45' cat, more light weight than most, and have aspirations for blue long hauls.
There are tons of threads in this and I think over the years I have read them all. Based on that theory and other people's experiences - and NOT personal experience, I hasten to add - I arrived at this position:

A JSD suitably sized deployed from rear, on suitably sized dedicated chain plates.

Anything deployed from the front runs risks of boat surging backwards with stress and risks of damaging rudders.

There is a lot of buoyancy at the back, and my take on forward-deploying things was that while the boat is facing the waves and seas nicely, the net effect is that the boat is looking the right way but ends up travelling backwards.

The JSD instead limits the forward speed and by all accounts I read, people tend to share that it just works. And my boat probably doesn't have a pooping issue.

I don't have a lee shore solution in the JSD. And I hope never to have to use it with weather monitoring solutions etc and ability to hopefully get out of the way of survival conditions. But in the overall scheme of things, for myself as a humble beginner, it felt like a must have if I have aspirations to cross oceans.

[rabbi]

Originally Posted by Palarran

Sorry, I should add that at some point it was suggested that you could put either a drogue or JSD off the bows of a catamaran - don't do this - please. Not a good idea at all.

I fully agree that a standard sized JSD won't work and is dangerous. The JSD is sized to allow ~3kn of speed downwind, and more if the boat is pushed by a breaking wave. Enough to damage rudders


But I can't see why one can't size the JSD for bow deployment. Anything that reliably creates enough drag without too much flex should do the job.

Does it make sense? I don't think so. A JSD sized for bow would be huge and heavy, a mess to deploy and retrieve. Plus very expensive.

[Paul L]

Well a 20 ft diameter parachute is roughly 315 sq ft. A 1 ft diameter cone is .78sq ft, so 400 cones would be in the ballpark.

[Palarran]

Originally Posted by rabbi

I fully agree that a standard sized JSD won't work and is dangerous. The JSD is sized to allow ~3kn of speed downwind, and more if the boat is pushed by a breaking wave. Enough to damage rudders


But I can't see why one can't size the JSD for bow deployment. Anything that reliably creates enough drag without too much flex should do the job.

Does it make sense? I don't think so. A JSD sized for bow would be huge and heavy, a mess to deploy and retrieve. Plus very expensive.

You did answer your own question right? It would make zero sense, even if I actually believed in using sea anchors at all with catamarans.

In any case, there are a lot of lovers of the JSD, I'm not one of them. I believe they slow the boat too much and would prefer a chute drogue if I ever bought one. To me the attraction to the JSD is a mental picture of someone sewing all the cones together with a bandana on their head from 30 years ago.

[rabbi]

Originally Posted by Paul L

Well a 20 ft diameter parachute is roughly 315 sq ft. A 1 ft diameter cone is .78sq ft, so 400 cones would be in the ballpark.

Only if total breaking force is a function of the surface area of the cone/chute opening and the effect of other factors like shape or diameter is small.

400 cones is a loooooong JSD.

[rabbi]

Originally Posted by Palarran

You did answer your own question right? It would make zero sense, even if I actually believed in using sea anchors at all with catamarans.

In any case, there are a lot of lovers of the JSD, I'm not one of them. I believe they slow the boat too much and would prefer a chute drogue if I ever bought one. To me the attraction to the JSD is a mental picture of someone sewing all the cones together with a bandana on their head from 30 years ago.

Some other poster asked if a JSD can be used like a para anchor. Which I think is theoretically possible not viable.


JSD and drogues serve different purposes in my view. JSD is for passive handling of survival conditions. Drogues are an aid for slowing down / steering in moderate conditions.

[a64pilot]

A JSD’s cones are 1ft across?
I’ve never seen one in actuality, only pictures and I didn’t realize the cones were so large.

[Palarran]

Originally Posted by rabbi

Some other poster asked if a JSD can be used like a para anchor. Which I think is theoretically possible not viable.


JSD and drogues serve different purposes in my view. JSD is for passive handling of survival conditions. Drogues are an aid for slowing down / steering in moderate conditions.

IMO there should be no such thing as passive handling of a catamaran in survival conditions. That is a huge difference between cats and mono's.

[thinwater]

Originally Posted by Paul L

Well a 20 ft diameter parachute is roughly 315 sq ft. A 1 ft diameter cone is .78sq ft, so 400 cones would be in the ballpark.

The cones are 5 inches, so about 6 times that many.

The effect of shape is minor between these, but the fact that the cones run in each other's wakes is major; the drag per cone is less when there is a string.

Based on testing, the answer is many thousands and a string a mile long.

The larger issue is that a long JSD towed at VERY low speed droops, and so it is not as "stiff" when it takes a hit. It tends to give a little. This is good for a drogue, but very bad for a chute, for reasons others have explained.


A long JSD is going to behave VERY differently from a chute.