Use of drogue/parachute anchor on Catamaran

[Bulawayo]

Thanks for the info. I'll certainly have a look but will say that Im very happy with my JSD (supplied by Ace Sails, and whom with I have no connection beyond my purchase).

Originally Posted by Fiorentino

Fiorentino’s published testing indicates speed-limiting drogues, like the Shark, have an advantage because they all require much less weight and are much easier to deploy and retrieve, because of their relatively small size. On average, the Shark is deployed with a 10 pound mushroom anchor attached to its Drogue Tail. However, for extreme storm use, any anchor up to 25 pounds can be attached to the Drogue Tail.

The Series drogue is heavier. In our testing, we have followed recommendations by Donald Jordon, who designed the Series drogue, to add a 25 lb. anchor for smaller boats and a 35-50 lb anchor for larger boats. In the 1987 USCG report written by Jordon, he said he added 35 pounds of chain weight to prevent his 90 element Series drogue from collapsing and the yacht from yawing during his tests.

Adding chain weight makes the Series drogue even heavier. The weight may cause it to deploy fast, but a sailor needs to be very careful to avoid entanglements around equipment stored at the stern. As you have noted, recovery is difficult. The Series drogue also is large and requires more storage space than the speed-limiting drogues.


You can watch a YouTube video we published of Pam Wall, provisioning expert and respected cruising lifestyle speaker, handling the various storm drogues, including the Series, to learn more.

[donradcliffe]

Originally Posted by Steady Hand

Good post.

But, I think the line that says "If you deploy a drogue from the bow and the boat is allowed to be thrown back, there is a very good chance you'll damage/break/snap off the rudder" could also include "sea anchor or parachute" in addition to the "drogue."

My point? Any boat thrown backwards on its rudder from a wave from the bow is likely to suffer damage, regardless of what kind of device is hanging off the bow.

If you read the USCG study on drogues, one phase of the reaction to a wave is the drogue pulling the boat backwards through the water at planing speeds. If the study is anywhere near reality, the rudder loads from drogues should exceed the rudder loads from parachutes.

I'm not sure the USCG/Jordan study is correct, but I'll let someone else go out in cyclones to test the theories.

[Fi2010]

Yes, our naval engineers and Zack Smith read the 1987 USCG report written by Donald Jordon. The report concluded the cone drogue, cone sea anchor, and Jordon’s Series drogue all tested successfully (equally) -- as long as the equipment was engineered and sized properly. There are several quotes throughout the report reinforcing the drogue/sea anchor success.

The report does reference something about the trough of a wave and rode going slack and how the yacht will commence to yaw, wanting to lie ahull, thereby leaving it partially or totally beam to the sea with the possibility of being knocked flat or rolled. According to Jordon, this was a problem for all of the devices, especially with his Series drogue.

To solve the problem, Jordon added 35 pounds of chain weight to prevent his 90 element series drogue from collapsing and the yacht from yawing during his tests.

There’s no indication Jordon used chain weight with the cone-style drogues or sea anchors during his testing process. Fiorentino tested chain weight with many different drag devices in the years after the report was written, and conclusively proved that weight placement is an important solution for all storm drogues. Not all manufacturers recommend chain weight.

Interestingly, we discovered weight placement is not as important for the para-anchors as with storm drogues since para-anchors hold more water. The extra force from larger devices helps reduce slack rode, assuming the parachutes are sized properly to a boat.

Chain weight or bigger para-anchors are not always the end all solution, so Fiorentino developed additional solutions to consider: The use of rode with less stretch, rode adjustment, shorter bridles, the Free-Flying riding sail™, and engine or sail power. These copyrighted solutions are referred to as Fiorentino’s Constant Rode Tension Theory/Formulas™. For more information look for the "Constant Rode Tension Seminar" on Fiorentino's YouTube channel and the Shark Drogue Manual.

Originally Posted by donradcliffe

If you read the USCG study on drogues, one phase of the reaction to a wave is the drogue pulling the boat backwards through the water at planing speeds. If the study is anywhere near reality, the rudder loads from drogues should exceed the rudder loads from parachutes.

I'm not sure the USCG/Jordan study is correct, but I'll let someone else go out in cyclones to test the theories.

[pir8ped]

A storm jib is enough to keep a cat dragging a drogue from going broadside in the troughs. I've spent a couple of weeks drogue dragging. In fact, there were times when the seas were still high but the wind had dropped where I found it useful to hoist a bigger sail for a while, to keep the boat moving and allow steerage. No copyright on this idea. Go for it.

[thinwater]

Originally Posted by pir8ped

A storm jib is enough to keep a cat dragging a drogue from going broadside in the troughs. I've spent a couple of weeks drogue dragging. In fact, there were times when the seas were still high but the wind had dropped where I found it useful to hoist a bigger sail for a while, to keep the boat moving and allow steerage. No copyright on this idea. Go for it.

Heck, Joshua Slocum trailed warps while using a storm jib.

Another simple solution can be to run the engine at idle; it won't feel lulls.

[pir8ped]

The engine solution is only practical is you have a nice pair of diesels I think. And if the weather is wild, well, there's plenty of wind for a storm jib.

Hey, I'm not claiming hoisting a storm jib with drogues is my own idea. Square riggers used to leave the top sails up, which seemed strange choice to me. Then I realised it would be to catch the wind high up, when they are in a trough, to keep the steerage.

[Fi2010]

Originally Posted by pir8ped

A storm jib is enough to keep a cat dragging a drogue from going broadside in the troughs. I've spent a couple of weeks drogue dragging. In fact, there were times when the seas were still high but the wind had dropped where I found it useful to hoist a bigger sail for a while, to keep the boat moving and allow steerage. No copyright on this idea. Go for it.

Sail balance can help balance a boat while towing a drogue. Lin and Larry Pardey, authors of the Storm Tactics Handbook also used sail balance while hove-to with a para-anchor. Practical Sailor asked us about our Constant Rode Tension theory and printed information about it several years ago. You can also view this information in Fiorentino’s Shark Drogue Manual, Rode Tension Seminar video or Fiorentino’s Parachute Sea Anchor Comparison video.

Gerrard Fiorentino, the company’s namesake, was known for his riggings skills and inspiration behind our current methods of development and instruction. You may be interested in reading Fiorentino’s history article which lead to the development of our current rigging techniques. The article is located in the about section of the Para-Anchor website.

[Fi2010]

Drew, Since the patented Shark drogue is already designed to do what you want without modifications, why would you recommend altering another manufacturer’s drogue to simulate the Shark? We already asked Evans Starzinger this question, but wanted to get your take on the subject. Wouldn’t manufacturers void their warrantees due to the risk of weakening the structural integrity of a safety device? This can inevitably lead to fabric tears and rode chafing against the drogue amongst other possible issues, including expense and time to complete the modifications.

To Set the Record Straight, The Shark Drogue Tail was originally invented for tandem drogue use in 2006 which is why our Drogue Tail has significant break strengths. However our published testing demonstrate a mushroom anchor attached to the Shark worked similar to a second drogue and was easier to manage. That’s why even though you can use the Shark drogue in tandem, we recommend mushroom anchor use instead.

Your statement “The bridle shown on page 21 is completely non-functional in confused seas…” we believe is in reference to our Shark Manual photo? Do you have any supporting evidence?

We disagree with your statement. Fiorentino learned years ago the importance of keeping the block of a pendant line close to the boat. Otherwise the pendant line will constantly go slack and all of the loading will pass over to one side of the boat, yanking the boat into an unfavorable direction and cause unwanted shock loads.

On page 22 of the Shark Drogue Manual Fiorentino shows a fixed bridle which can be used interchangeably for speed-limiting purpose and emergency steering. However, some sailors may prefer the pendant line so they can adjust the amount of rode deployed. It’s personal preference.

And Drew, you are really stretching about a drogue hitting someone in the face. There’s a photo on our website where the Shark is tossed into the air. That was only done for photo purposes to show what the Shark looks like as it unfolds. Fiorentino’s Shark Drogue Manual and YouTube channel demonstrate the dropping of the Shark away from the transom, not tossing it into the air. Even if we did recommend tossing it into the air and, again, we don’t, it’s unlikely the device would ever hit anyone in the face because it’s designed to sink immediately as shown in our drogue comparison video.

Originally Posted by thinwater

The way I have done this under load is to attach an extension (20' with 2 eyes) that brings the rode up to the transom. Then I added the second drogue, cast off the bridle, and let the rest of the rode run out until the second bridle catches. The legs of the first bridle simply train alongside the rode.

I've run tandems with most drogues by simply running the rode through the center. The Delta may be the only one requiring a simple mod.

I'm not sure Fiorentino gets the point on tandems. The manual says it is the same as one drogue with more weight, which I don't believe is true; the separation makes a big difference in waves.

The bridle shown on page 21 is completely non-functional in confused seas; try it and you will see why (too short and geometrically unstable). I also found his "throw it in the air" deployment system comical; try that in enough wind and the drogue will just hit you in the face, obviously. But the drag numbers seem right.

[SV THIRD DAY]

Originally Posted by 805gregg

Or another way, just go with it at 20 knts. (Ovive sailing fast in the South Pacific) youtube

Yes but look what happened to Ovive when it ran over a log. Check out this article. Storm Drogue Steering Drouge Shark Drogue.

[thinwater]

Originally Posted by pir8ped

The engine solution is only practical is you have a nice pair of diesels I think. And if the weather is wild, well, there's plenty of wind for a storm jib.

Hey, I'm not claiming hoisting a storm jib with drogues is my own idea. Square riggers used to leave the top sails up, which seemed strange choice to me. Then I realised it would be to catch the wind high up, when they are in a trough, to keep the steerage.

I was just mentioning one more idea for the quiver. It's always good to have more ideas. For example, the engine works while sail adjustments are been made. And of course, the engine is the whole thing when crossing a breaking bar, the only time I have needed a drogue. Worked great.

[Fi2010]

Drew,
We recognize the amount of effort involved in conducting tests, whether it’s a side by side comparison of the manufacturers’ drogues or in the case of your tests, the mixing of model testing with a couple of manufactured drogues, and third party information.

We hope you consider separating test data so others can better understand your opinions. For instance, test #1 was with models, test #2 was with such and such manufacturer(s) drogue, and test #3 is from this third party organization(s)…

Can you tell us which manufactured drogues you tested and which ones were only 1/3 scale models?

Originally Posted by thinwater

Tandem drogues are an interesting topic. Starzinger wrote somewhere that he has done this with good success (A Delta drogue with something else trailing), and one of the earlier posters said they were set up for this. I took the hint and did both small scale testing (easier and safer to simulate really bad conditions by overloading smaller drogues in 30-40 knots over a bar) and full scale testing. While placing 2 ground anchors in a row is nearly always bad (the intermediate rode tension does bad things to them), the oposit seems to be true of tandem drogues. The fact that JDS is so robust suggests this is true.

• The closer drogue will come out of waves, but it will not be thrown forward; the secondary holds it back and down, pulling it back into the meat of the wave within 1-3 seconds.
• The contracting rode will not rubber band the drogue forward when it pulls out. When a drogue pulls out of a wave, the rode looses tension and shrinks, easily 10-20 feet, allowing the drogue to fly forward with the breaker. The second drogue prevents this.
• Unless the spacing is very poor, they will never be out at the same time.
• The secondary will run deeper (it has ~ 1/2 the rode tension).
• Drag forces are MUCH more steady; instead of 30-50% variability, only 10-15% variation (not including affects of waves hitting the boat). At least in part, this is because the waves move over them at different times. Less pulsation and chafe on the rode and bridle.
• Drogues are smaller and thus easier to handle. Important once the boat reaches about 45 feet.
• Drag is adjustable; let out one, then let out the other. Same with recover; you can winch this in with a light storm load on it, but I bet that's impossible with a JSD.
• I liked the Galerider as the trailer and the Seabrake closer; the Seabrake generates a lot of force and is easy to recover, and the Galerider is so smooth. But I tried this with 5 brands in many combinations and the differences were pretty minor. The big factors were rode length, intermediate rode length, and bridle adjustment. As Starzinger said, any calculations based on wavelength are fuzzy at best; the "answer" often varied in minutes as we passed over bars and WL changed. The right answer generally seemed to be "enough."

A little more complication, but based on my limited experience, it is the direction I would lean. But we will only learn the important stuff if folks rig for it and try it.


My only other observation is that you need to test your theories in rough but not desperate weather. A lot of the stuff in books is wrong, or at least wrong for your boat. I'm guessing some of the authors never actually tried it themselves.

[Fi2010]

Drew,
Looks like you removed the photograph showing some of the models for your test (the ones you built yourself?) from your sail-delmarva blogspot.

Your Delta model looks similar in size to the Seabrake model. If sized to the same boat, the manufactured version of the Delta is actually smaller than the Seabrake. At least this is what Zack Smith witnessed and a professional videographer filmed during a Sail Magazine 2007 drogue comparison test later published in May 2008, entitled “What a Drag.”

Our testing experience shows the Delta drogue is easier to recover than the Seabrake, partly because it’s smaller and has less drag. The Galerider is also easy to recover because it has much less holding power since water passes through its large open webbing. If chain is added to the drogues then more work is required for recovering the equipment. Fiorentino’s FPA Technical Report 136, among other Fiorentino published reports and comparison video support these findings.

Originally Posted by thinwater

There are 2 problems with a single drogue, in my experience:

• If the boat is big (Delfin) the drogue will be hard to recover filled with water; Seabrake is not bad, but Delta is a bugger when full and I know my back could not handle the one you need! A Galerider would need to be quite large to give good braking force, but they are super easy to handle.
• A single drogue can (will) always pull out of steep waves faces. Sort of like being anchored on too short scope. This becomes worse and conditions become worse.

[pir8ped]

Thinwater,

I've never had to cross a breaking bar with my cat, but I'll have a drogue to hand if I do. Good idea. Another for the quiver!

[JohnT]

I wrote the story below a few years back and it may be of interest to some on this thread. I have sailed quite a few catamarans that had the JSD and para anchors, but never had the necessity to use them. I am not advocating that my method would work on all cats and, of course, the vessels weight and windage plays a massive part in the amount of resistance needed to be formed by a drogue.
----------------------------------------------------------------
The writing below gives a bit of insight to one of my experiences. It occurred in the South Atlantic and the measures taken if it had occurred in the Med would most likely have been different.

I have personally had four such situations in all the years whilst sailing (I am a delivery skipper). One of them was as follows:

In mid 2007 I was en-route from Cape Town with my first port of call being Jamestown, St Helena Island, a trip of 1700nm which I had sailed 28 times before. I was delivering a new 40’ Leopard catamaran from Cape Town to Fort Lauderdale. I had on previous trips experienced heavy seas of 8 to 9 metres and 45 knot winds turning from the south to northwest whilst a cold front passed by. None of these seas had been breaking or too steep – I had simply dropped sail with the exception of a handkerchief size bit of foresail and run with the wind and swell until it was comfortable to turn back on course and continue NW once the front had passed.

On this trip, however, things were slightly different – about 700nm out of Cape Town I started experiencing 9 to 11 metre steep swells with the occasional breaking waves as a huge frontal system approached. The wind picked up to just over 50 knots, gusting to about 65. In reality the swell was every about 7 or 8 seconds but seemed to be 4 seconds. We had started surfing uncontrollably down the waves and needed to do something to prevent this or we would be rolled or pitch-polled. The daylight was fading (amazing how the bad stuff always happens at night) when I instructed the crew (3 POB) to haul out our spare anchor warp, a 22 mm nylon line of 100 metres in length. We attached each end of the line to the mid-ships cleats and then lead it aft and around the aft cleats as well. Then dumped the entire remainder overboard and dragged it as a “U” behind the boat. The object was to stop the boat surfing down the front of the waves. It did not help! As we accelerated down the front of a wave the line simply pulled out of the water, forming no resistance at all. I needed to add weight to the line to keep it under water.

So, all hands pulled the line in and I took a 8 metre length of anchor chain and a large shackle and fastened the chain to the line. I did it so that the shackle could slide down the warp and “self centre” itself at the back of the “U”. It worked! There was now enough resistance to stop the cat surfing down the front of the waves. We took a lot of white water over the stern of the boat but she lifted comfortably to let the waves pass under her.

At about 02:00 I was on watch when I heard the “big one” come. All I heard was a few seconds of “Shhhhhhhhhh” before it hit. A wall of solid water came over the stern of the boat and blew out the saloon door. We took on about 2 tons of cold Atlantic in a split second – it took the bilge pumps over an hour to pump the hulls out. This was the only wave that actually caused any problems. Although the boat took water and violently shuddered when the wave hit us, it remained stable and kept going in the right direction with the warp keeping the resistance needed to prevent the boat taking off uncontrollably.

When we arrived in St Helena a week later we re-installed the sliding door and had no further problems on the delivery.

On subsequent deliveries I have always had the spare anchor warp and chain “ready for deployment” before I have departed. I experienced no chaff on the warp from the movement of the shackle or any at the cleats.

What would I have done differently – nothing! What would have happened if we did not have the warp and chain – I would more than likely not have been writing this post, simple as that! The route sailing boats take to St Helena in not near a shipping route and thus, if things had gone “pear-shaped”, there would not have been much chance of rescue.

[thinwater]

^^ I towed 200' (60M) of 1/2" (20mm) line + 30' of 3/8" chain in a loop, much as described, during testing of a number of commercial drogues, for comparison purposes. This data was not used in the article:

• 7 kt = 65 pounds
• 10 kt = 130 pounds
• 12 kt = 180 pounds

This is smaller than described above and less weight, so perhaps the force was double in John's example. For comparison, this is about 5 times less than a Galerider 30.


Is this enough to really help? Depending on the situation, yes, it appears so. With smaller boats, I suspect it would not be enough; others have said this. And yes, weight in the center is absolutely vital. The more weight, the less the chance of pulling out of a steep wave. Remember that steep waves act like short scope at anchor, allowing drogues that are near the surface to pull out easily.



The drag from a warp is very steady, and it seems to cut waves down a little. In this way, perhaps, it is a little more effective than the low drag numbers suggest.



It also has the advantage of being much easier to handle than conventional drogues. You just winch in one end. It is even easier if the weight is secured to the center or at least in a way that it cannot glide off the end. Then you can let one end go to winch it in, which is much easier. Perhaps it makes a lot of sense in conditions where you can't decide if a drogue is worth the effort.


John, why did you secure it to cleats instead of the sheet winches? The load could not have been that high. I'm curious. I can see anchoring a chute to cleats, but none of the drogues I tested overpowered the winches, even at surfing speeds.