Use of drogue/parachute anchor on Catamaran

[svrevelations]

Originally Posted by SVNeko

Good anecdote. Thanks. Did you notice any steering effect deploying only one.

After we deployed the first drogue (starboard side), we did notice that the autopilot started steering slightly in the opposite direction (to port). At the time, we did not specifically check how much effect the drogue had on the steering of the yacht - our main interest was to see the effect it had on the speed of the yacht.

[kimberlite]

The Jordan drogue is about 300+ feet long and mine has about 157 8-10 inch diameter cone shaped parachutes on it. The brilliance of the Drogue is that there is always something in the water. Especially since there is 20-30 lbs. of chain on the end.
A parachute is launched from the bow, not a place to be in a storm and is one device. It is also a major pain to retrieve. The Jordan is easy. All other devices such as the Gale rider is one divice that can pop out of the water.
I will stick with the Jordan.
ERic
Kimberlite

Originally Posted by Don C L

I can certainly see how a drogue could be pulled out of or through a wave, but a properly sized and inflated parachute should be pretty much stationary, no?

[thinwater]

Originally Posted by Revelations

After we deployed the first drogue (starboard side), we did notice that the autopilot started steering slightly in the opposite direction (to port). At the time, we did not specifically check how much effect the drogue had on the steering of the yacht - our main interest was to see the effect it had on the speed of the yacht.

Why not a bridle, which should have nearly eliminated the need for the pilot to work at all and added a lot of stability? Just curious.

[timbenner]

Originally Posted by Steady Hand

The most informative site and best info related to drogues I have found is a site devoted to the Jordan Series Drogues (JSD). It contains numerous pages describing the science of waves, the technical design of drogues, anecdotes about use, links to specs so you can make one yourself (simple to do) and a source where you can buy ready made ones too.

The description of sea anchors and drogues is there on the pages of that site too.

Jordan Series Drogue

I also encourage you to see the link on that page for the USCG Report of the lab and field testing of the JSD compared to parachute style drogues and sea anchors. Especially read the concluding paragraphs of that report, found near its end. It is a PDF file document. When you open the PDF, look down near the end to find page 68 of the PDF which is page 59 of the the Report. Look for the section 6.4 "Boat Design" and begin reading there. The PDF pages 68, 69, 70 should give you some of your answers. Here is a link to the Coast a Guard Test Report:

http://jordanseriesdrogue.com/pdf/dr...uardreport.pdf

My Summary: Based on what I have read on the topic, I would get a JSD if concerned about surviving a "survival storm" at sea.

Also, the JSD design and specifications to make one using cloth and rope is open source info. The designer, Mr. Jordan, wanted all sailors to have access to the design, so they could make their own. It requires the use of a sewing machine and simple materials and some hours. Some cruisers have made their own while on a voyage.

--------

Note! I do not own a catamaran or big mono. But, I have read comments by cat owners and mono owners that have differences of opinion on what they would use or do in a storm. Everyone has an opinion. The USCG Test Report and several other things I have read on this topic (testimony by highly experienced sailors who chose the JSD), are more convincing to me.

Ditto - I second that advise. JSD was developed by Jordan and the Coast Guard after a tragic trans-Atlantic race, when a number of boats were lost to large seas. It was developed as a way to avoid broaching in large seas. I bought one for my Lagoon 380, in the event that I make the trip past Columbia, where large seas are common.

The JSD acts like a large rubber band holding the boat back from plunging down the face of a large wave and broaching at the bottom. Which is when and how you flip a catamaran. After I read an account by 2 surviving crew of a catamaran that broached, killing the captain in the mid-Atlantic, I went and bought one. I mounted a spool in the starboard, forward crash compartment, where it's stored on the spool.

The big challenge with the JSD is where to attach the two bridle legs that attach the JSD onto the transom of the boat. My aft cleats are forward of the corner stantions, so the corner stantions would get damaged by the bridle movement. My cleats on the transom can't be used because the bridle load would be near vertical to the cleats. Cleats are designed for horizontal loads.

For this reason, I deck mounted bollards to attach the JSD just above the engine / aft cabin bulkhead, forward of the transom steps. This allowed me to build-up fiberglass matt and epoxy under the deck and down the inside of the top transom step, down the inside of the gunnel and down the engine room side of the bulkhead engine room / aft stateroom bulkhead. This tied the bollards foundation into major structural components of the boat. Then added 1/4" of additional fiberglass matt and epoxy pad for the bollard to sit on deck. Next drilled the 4 mounting holes through the deck, through the balsa core, BUT NOT THROUGH THE UNDER SIDE FIBERGLASS OF THE DECK. Then hallowed out a couple of inches of the balsa around each hole and filled with epoxy to form a piling to support the bollard and keep from crushing the deck, while tightening the mounting bolts. Finally drilling the center of the pilings for the mounting bolts and bedding large 1/4" aluminum backing plates in thickened epoxy under the deck.

ALL OF THIS FOR SOMETHING THAT I HOPE TO NEVER USE!! We all know that there are 60'+ waves in those 40' seas. The new science developing on rogue waves proves that they are not that uncommon!!

I have NO actual experience with any of this and hope it stays that way.

[Factor]

Agree - a drouge is a great device but should be used on a bridle, it can act as a great emergency steering in heavy weather

[kimberlite]

With the jordan drogue the wheel is tied down and the drogue is launched. Takes 3 minutes

Originally Posted by thinwater

Why not a bridle, which should have nearly eliminated the need for the pilot to work at all and added a lot of stability? Just curious.

[kimberlite]

We sailed nonstop from NY to Santa Marta Colombia this November. stiff breze all across the gulf.

The marina inSanta Marta is beautiful, unfortunately there is a coal burning plant across the bay. In 3 days your boat is flocked BLACK.

Later in the winter we sailed upwind to Guadeloupe-- NASTY NASTY
35 -55 knots on the nose for 9 days.
Next time I will go down wind.
The seas around Colombia are a little strange with big waves coming from
odd directions.We were slapped and knocked over but not down numerous times.
fair winds,
Eric
ps my son put
My son Lowell put this together for me.
It was the nice part of the NY to Colombia trip.
.

https://vimeo.com/169608486
PASSWORD: gsm.

[svrevelations]

Originally Posted by thinwater

Why not a bridle, which should have nearly eliminated the need for the pilot to work at all and added a lot of stability? Just curious.

Buying the drogues was a last minute decision, we received the drogues literally hours before our departure and there was simply no time to do a proper bridle setup. We therefor opted to deploy each drogue with it's own rode - which we rigged up whilst underway.

We have since changed the setup which now incorporates a bridle with stainless steel thimbles - also with the option of deploying the drogues in tandem. The setup now allows for the second drogue to be 50 meters behind the first drogue.

[Don C L]

Originally Posted by kimberlite

With the jordan drogue the wheel is tied down and the drogue is launched. Takes 3 minutes

Given your experience what do you think of using the para-anchor to ride out the storm vs. using the drogue to run with it?

[timbenner]

Originally Posted by kimberlite

ps the article had it wrong we saw the spit buoy in Bermuda but never entered the Island the trip was nonstop.

Hope you all were wearing your brown corduroys!! Thanks for sharing that story.

[kimberlite]

As I previously mentioned the para anchor is one device in the water and launched fromthe bow. Not a place to be in big seas. you also have the possibility of the thing popping out of the water and more importantly the boat is going backwards putting strain on the rudder..In addition it is a pain to launch and more difficult to retreive.

The drogue is comprised of 157 devices some in the water and some on the next wave , some out of the water. It is a no brainer to launch or retrieve. In addition it is launched from the stern by dropping the chain in the water and feeding the first 10-15 fet out by hand , after that just sit back an marvel. An important feature is that you are sailing downwind at about 3 knots in 65-100 knots of wind with no strain on the rudder. The only negative is that if a wave is breaking you are going to get wet.
This happened numerous time and all I saw a couple of times were the masts sticking out of the water. Amles love this weather--one crewmember on watch in the center cockpit was up to his armpits in water and he is 6'2".
the Amel has 4 inch scuppers . ,the cockpit drains in 15-20 seconds.

Down below we were relaxing as much as possible , no drips or squeaks-- we store paper towels in the bilge it is that dry.
Of course someone needs to be in the cockpit in case we have to cutt the drogue away due to an oncoming ship.
fair winds,
Eric

[Bulawayo]

Originally Posted by Pieter

Hello friends,

Recently i saw on youtube a film of a Cat in a major force wind (i have to guess around 40-45 knots).. they didnt have any sails up, going with the wind and the waves, and they had this drogue/parachute type ancor deployed. For this first time i finaly had a visual of how this ancor actualy works, and i could also imagine how this would work if you would deploy it from the bow and keep the bow into the wind as if your anchor would be dragging. We already sailed the coast of Brazil, spend a year in the Caribbean, went across to Europe and via Africa back to Brazil on board of our FP40ft.. During this voyage we never were in rough weather so i never thought of it. Now we are planning to go to the Pacific and i plan to prepare to have this item on board. Questions i have for now:
1. What is the difference between a drogue and a parachute?
2. Having read Eric Taberly.. he was always against using those kind of "breaks" especial deployed from the stern..
3. It depends on the situation at hand if you want to deploy from the stern or the bow?
4. Is this a must have on board item?

Thanks for your remarks and insights.

We do have experience with the our Jordan Series Drogue. We bought ours complete with Tylaska J hooks (SWL, 15000lb) for attachment, direct from Ace Sails. It is a hybrid version, Dyneema and nylon. I feel I must comment on one point. These are not easy as easy to make as many seem to give the impression. Sewing the cones is not straightforward if the recommended material is used. Unless you have a Sailrite sewing machine or something similar, very heavy duty, you shall destroy your sew machine. We have seen this happen to friends. It is not particularly technical, it is just very time consumeing and hard work. Friends thought they would save money by buying the kit and putting the drogue together themselves. After several months they sold the kit onto another boat having bought a complete one.
A long time ago I found the drawings for the 'chain plates' to attach the bridle to, aft. Similar to what has been mentioned elsewhere these are are backed by 18mm meranti spreader plates around three times the size of the chain plates. We reinforced the hulls with several layers of cloth before through bolting above the water line - the chain plates are horizontal and the hull solid at the mounting point. The drawings of the chain plates follow. If the image does not attach please pm me and I shall send direct as each time I tred to attach the drg (240kb) but it is rejected as being too big and I do not know how to attach a picture, or if I am allowed to.
Please note that there is usually no need to go to ballistic lengths of super reinforcement at the bridle or something else shall fail first. We contacted our boat designer and received advice as to the level of reinforcement and then doubled that. As he said, there is a limit to reinforcement - do you want to tear the whole end (he used other more colourful language) off the boat or just wany something else to fail first leaving your hulls substantially intact and seaworthy? Look at the what is the weakest component in your set up - my understanding is that one leg of the bridle should fail first. Additionally, realistically, how much load can be ablied? Great than being anchored to the ground? Check how your windlass is mounted or the anchor bridle attachment points - there is no need to exceed these.

[rabbi]

Originally Posted by Bulawayo

As he said, there is a limit to reinforcement - do you want to tear the whole end (he used other more colourful language) off the boat or just wany something else to fail first leaving your hulls substantially intact and seaworthy?

Good point.
In our Lagoon 410 we just beefed up the aft mooring cleats: added cloth and big backing plate. Other people suggested more substantial reinforcement, and closer to the waterline.
But do I want to loose hull integrity (which would certainly sink us over time) or do I prefer to let the JSD go?
We never used our JSD in storm conditions, only to avoid landfall at night in 35+kn. Smooth & elastic ride, autopilot off. Sold it with the boat.


Now with our Mahe we don't carry a JSD (only coastal sailing).
Last fall we had a strong 30min thunderstorm with solid 60kn and higher gusts. The waves were just 3-4m but very steep. We did 12+kn under bare poles and exceeded 14kn easily when surfing down a steep wave.
Even though not a life threatening situation a JSD would have helped tremendously to calm things down (more so as the motion stirred up the diesel bug in the tank and both engines died with clogged pickup lines, but thats another story )

[REsCat]

I am encouraged by the ideas and accounts related above regarding the JSD as a must have safety tool for Cats/Monos doing offshore passages or planned ones on a regular basis.
It would seem that controlled "running" away from storm,survival conditions with a relatively "easily/safely" deployed device would be a preferred option for many versus being up at the bow(s) in very dangerous,difficult conditions which are getting worse by the minute making deployment and adjusting/maintaining very problematical. Rudder integrity also seems to favour the drogue approach.

The other issues such as breaking waves landing on the back decks/cockpit and dissapating is a whole other consideration to be dealt with as well as proper attachments for the bridal. I have 4 substantial aft cleats that I think will work for this system and I will beef these up as well as plan for "large" breaking waves on deck if such a thing can be done for Cats of various stern profiles.

Bob

[thinwater]

Originally Posted by rabbi

Good point.
In our Lagoon 410 we just beefed up the aft mooring cleats: added cloth and big backing plate. Other people suggested more substantial reinforcement, and closer to the waterline.
But do I want to loose hull integrity (which would certainly sink us over time) or do I prefer to let the JSD go?

The problem with this line of reasoning is that it is exceptionally difficult to engineer. The bridle is subject to chafe and both polyester and nylon are subject to fatigue more rapidly than metal (in general). So to make certain the line would fail first means it will very likely fail from fatigue or chafe. Estimating the strength of the layup is probably beyond everyone on this thread (if you are a mechanical engineer or equivalent, you have my sincere apology). It is complicated and is a skill set we don't have... and there are many certainly skills engineers don't have. The my practical answer (I am an engineer) is to be certain that the hull is stronger than the fasteners (in this case cleat bolts in shear/tension). There is NO reason to assume that chain plates will pull a chunk out of the hull. However, I personally feel that effort is better spent making certain that the cleats are up to the job, since they offer far more versatility.