Towing Warps - Actual Test Data?

[goboatingnow]

I come to this post late

but

The Pardeys are right about one thing - while running, eventually there will be one of them with your name on it.

Very little of what the Pardeys say is applicable to modern, small underbody yachts. I personally have streamed warps in a very very bad strorm in the north altantic, and yes it does work, primarily it keeps ( as one poster put it) your ass pointing into the waves. However I would caution using it to slow the boat down a lot.

As to sea anchors, ie off the bow. I cannot find in my heart (or boat) a place for them. enmorus snatch loads, difficult retrival and the whole concept of unattended inactive response to heavy weather. I found forereaching under engine with a scrap of main to be far more useful, The engine gives you good directional stabilty and contril and teh main helps steady the boat. remember lots of techniques were developed before reliable modern engines. Heaving too, is a joke in most modern sailboats, try it on som eof the benes, bavs or jeanos and see what I mean. ( ps not just in a f3-f4). all that happens is that the boat ends up nearly lying ahull or (as they are light) is pushed through the wind and happily sails off.

[thinwater]

Originally Posted by goboatingnow

I come to this post late

but

Very little of what the Pardeys say is applicable to modern, small underbody yachts. I personally have streamed warps in a very very bad strorm in the north altantic, and yes it does work, primarily it keeps ( as one poster put it) your ass pointing into the waves. However I would caution using it to slow the boat down a lot.

As to sea anchors, ie off the bow. I cannot find in my heart (or boat) a place for them. enmorus snatch loads, difficult retrival and the whole concept of unattended inactive response to heavy weather. I found forereaching under engine with a scrap of main to be far more useful, The engine gives you good directional stabilty and contril and teh main helps steady the boat. remember lots of techniques were developed before reliable modern engines. Heaving too, is a joke in most modern sailboats, try it on som eof the benes, bavs or jeanos and see what I mean. ( ps not just in a f3-f4). all that happens is that the boat ends up nearly lying ahull or (as they are light) is pushed through the wind and happily sails off.

... in general. One size never fits all, either the storm or the boat.

Catamarans, sails off, are more like rafts; the balast won't flip them back up, but nether does mass and and a deep underbody restrict them, so the limitations and requirments are different. Cats do very nicely, in general, on sea anchors, where with monohulls the results are more mixed. Cats don't in general like to heave-to or lie ahull. Fore-reaching under power has worked in some pretty bad conditions - no balast, but 2 widely spaced engines makes keeping the bow pointed with very little way on reasonably easy... until the risk becomes getting thrown backwards and then methods must change. Broaching and rolling is a smaller risk; pitch poling or digging a lee bow and capsizing greater.

Different.

[Joli]

Multis certainly prevent different issues. What is the max wave height that you would tow a warp? Or would you base your limit on max speed?

One option that hasn't been mentioned is fore reaching but, I don't think it would be an option for a multi? Fore reaching would probably be our prefered option if the poop really hits the fan. More work for sure but you can at least pick the spots you like for crossing the crests.

[thinwater]

Originally Posted by Joli

Multis certainly prevent different issues. What is the max wave height that you would tow a warp? Or would you base your limit on max speed?

One option that hasn't been mentioned is fore reaching but, I don't think it would be an option for a multi? Fore reaching would probably be our prefered option if the poop really hits the fan. More work for sure but you can at least pick the spots you like for crossing the crests.

... is only an illusion.

Sorry, I don't mean to be difficult.

But when it is really rough and the waves are chaotic, forereach slowly at a few knots (because beating is more of less impossible), with waves only ~ 5-10 seconds apart, I can only realistically adjust my possition by about 10-15 feet - not enough to matter in the case of a serious break. Waves are popping up everywhere and all I can do is adjust my attidue, not avoiding them but taking the big ones with a little more speed and a little more straight-on.

Steering works and is more comforatble when it is rough but managable.

Drogues and sea anchors are for when that isn't working anymore. Speed isn't a deciding factor; it is when control is being lost, your surfing too fast downwind (too fast is a variable number), and when you need a rest.

[thinwater]

Originally Posted by thinwater

... is only an illusion.

Sorry, I don't mean to be difficult.

But when it is really rough and the waves are chaotic, forereach slowly at a few knots (because beating is more of less impossible), with waves only ~ 5-10 seconds apart, I can only realistically adjust my possition by about 10-15 feet - not enough to matter in the case of a serious break. Waves are popping up everywhere and all I can do is adjust my attidue, not avoiding them but taking the big ones with a little more speed and a little more straight-on.

Steering works and is more comforatble when it is rough but managable.

Drogues and sea anchors are for when that isn't working anymore. Speed isn't a deciding factor; it is when control is being lost, your surfing too fast downwind (too fast is a variable number), and when you need a rest.

A thread on storm managment will go far and wide and breed conflict.

[thinwater]

Originally Posted by Albro359

Here's what the people at SeaBrake had to say in response to my query about stretch or non stretch line :

When Seabrake is used as a drogue underway (ie off the stern) a low stretch rope is recommended to ensure continuous adjustment to drag levels in relation to boat speed. A stretchy rope will reduce the effectiveness of the unit.
Shock loading is not an issue as neither vessel or Seabrake will be acting independently from each other, the drag levels the Seabrake unit generates always relate directly to boat speed due to the variable pressure/drag wave Seabrake creates.

When a vessel is attached to a fixed unit (ie one not moving through the water) such as at anchor, attached to a dock, or to a lesser extent attached to sea or parachute anchor which generate relatively high but constant drag rates, shock loading of fittings can cause problems this is one reason why stretchy warps are traditionally utilized in these situations.

Also the Seabrakes warp should not be a buoyant material as weight of warp and chain combine to ensure the Seabrake unit stays below the surface.
Braided polyester is usually recommend as it is low stretch, does not float and is relatively cost effective. Earlier models were actually supplied with even lower stretch Kevlar core ropes.

Makes a difference too. I posted this on my blog:

• Chain. I tested the drogues without chain, for convinience and because I was in shallow water (7 feet). In practice , wieght is needed to keep the drogue under the particle rotation of a wave, or at least 12 feet. Given the average load for the PDQ 32 in 60 knot winds (50 knots at the surface, gusts and waves don't count because the drogue surfaces slowly and they will average out, the drag of the hull must be subtracted) will be about 400 pounds, that 240 feet of rode are deployed, and that chain weighs about 65% as much underwater, about 400x12/(240x0.65)=30 pounds of chain will keep it down. That would be about 40 feet of 1/4-inch G4 or 20 feet of 3/8-inch proof coil. Seabrake recomends 10 feet, but user experience suggests that may be light for extreem conditions. I think a little more sounds better, but I will not exceed my calculated value - too much wieght can introduce other problems, including too much up and down movement. Adding weights or chain in the center of the rode has been tried with sea anchors - that center of the rode jumps around a lot and that is no longer recomended. The Small Shark recomends adding wieght to the tail and has a fitting for that purpose.

[barnakiel]

Originally Posted by thinwater

Could you expand on why you are not getting consistent drag?

I think the problem is that the waves have consistent "wave-length" only in the mathematical models. I have tried to measure the time gaps between big ocean swells passing my boat by. Twice - Atlantic Ocean 2003 and then the Indian 2006. In each case I found that there is pretty consistent average, but individual waves come at anything between +/- 50% of the average. Not every one, sure. But what if the untimely one comes exactly when I get a kick from a breaking crest and need the drogue's action most???

So, to me, the Jordan rules. But I cannot have it - it would mean I have to devote one very long line to have the JSD that I use - how often? Impossible in a small boat like mine (space!).

So, Sea-Brake, but - as explained - inconsistent! Thus thought of supplementing what I have with another, smaller one - inline, beyond the real thing. (Sort of like a mix between the JRD and "series Sea-Brake".

Regards,
b.

[Southern Star]

Thinwater, thanks for putting all of the time and effort into this test. I am in the process of fitting my Solaris Sunstream 40 with a JSD and, to me, the advantages seem overwhelming: since the series drogue will have resistance from the cones throughtout its entire length, one need not worry about where to set it in relation to the wave train; further, it will not be subject to the same kind of sudden jarring force that a sea anchor will if it is out of synch, or collapses and refills.

Your boat, like mine, has what amounts to a well protected center-cockpit and this should improve the safety in following seas that is naturally provided by the bouyancy aft. Nevertheless, I do have some concerns about the occasional breaking wave from astern and, as a result, am looking into fitting a custom made, watertight, anodized aluminum companionway door with dogs (see the new thread under the refit heading, 'Watertight companionway doors').

Brad

[thinwater]

Originally Posted by Southern Star

Thinwater, thanks for putting all of the time and effort into this test. I am in the process of fitting my Solaris Sunstream 40 with a JSD and, to me, the advantages seem overwhelming: since the series drogue will have resistance from the cones throughtout its entire length, one need not worry about where to set it in relation to the wave train; further, it will not be subject to the same kind of sudden jarring force that a sea anchor will if it is out of synch, or collapses and refills.

Your boat, like mine, has what amounts to a well protected center-cockpit and this should improve the safety in following seas that is naturally provided by the bouyancy aft. Nevertheless, I do have some concerns about the occasional breaking wave from astern and, as a result, am looking into fitting a custom made, watertight, anodized aluminum companionway door with dogs (see the new thread under the refit heading, 'Watertight companionway doors').

Brad

... it in in the CG report I refferenced, though I can't argue against stronger. I am considering doing something too.

[thinwater]

I contacted the main ones - no point in naming names - and got no response on the issue. Seabrake says minimal stretch. All of the others specify nylon lines, though by implication the JSD suggests no stretch (they do allow high-tech lines and one of the stated virtues is more immediate braking).

It seems they are not at ease making statements by e-mail or on-line about the behavior of drogues in wild weather. Clearly they must have policies against responding to forums, as many companies do. So we post the data we have, we guess and, we share experience.

[Fi2010]

Hi Thinwater,

Sorry it took us awhile to get back to you, but we wanted to take time to go through your material. Fiorentino has now reviewed your personal blog site (sail-delmarva) which describes your tow test and some of the sources cited in your extrapolation of data. Per your e-mail request, we are posting our conclusions to this forum.

As you note, you used multiple sources to extrapolate data. This can be tricky at times as sources can be mixed-up or information misstated. I think this is what led to misquotes about several manufacturers’ products, including the company I represent.

For example, you state that you have extrapolated information about the Delta, Gale Rider and Shark drogues and say that they are steering assistance devices rather than slowing devices. Our response is that all three are designed not only for steering, but as speed limiting drogues intended to slow the boat. Shark tests completed by Fiorentino show it is highly effective in slowing boats in heavy seas.

Using proper weights to sink drogues is an important issue for boaters. The Seabrake, which you mention positively in your post, uses a long length of chain to sink it properly. Other drogues use the same technique. These long lengths of chain can be difficult to deploy in rough weather and are nearly impossible to retrieve without banging your boat’s hull. Fiorentino designed the Shark with a Drogue Tail so a mushroom anchor can be used to sink the drogue thus eliminating the need for chain. The “Sail” magazine article that you reference actually gives kudos to this feature plus the Shark’s ease of use.

Because of your interest in data, you may want to take a look at a drag test that Fiorentino’s Zack Smith (drag device inventor) managed with Steve Dashew (author). Check out Dashew’s drogue report at SetSail » Blog Archive » Drogue Testing. Evans Starzinger and Beth Leonard also attended the drag test.

In an effort to support your test results you quote data from the “What a Drag” comparison article by Kimball Livingston. We are familiar with this “Sail” magazine article at Fiorentino and feel some significant points have been overlooked in relation to the Seabrake. For example:


The Seabrake tested was actually a GP30L a larger model than the GP24L. Livingston made mention of this misprint, clarifying how the GP30L is sized for vessels 36-55 feet and not for boats to 35 feet like the GP24L. We bring this to your attention because this makes your “comparison between units” inaccurate.

There was a very strong and fluctuating current present during the “Sail” drag test compared to your tow test. Tidal currents can dramatically affect test results.

The Seabrake was not rated better over any other drogue in the article as you indicate on your website.

The Seabrake is a speed-limiting drogue like the Delta, Galerider, & Shark. It does not belong in its own separate category as you suggest, nor is it similar to the Series Drogue.

The Seabrake lost its SOLAS approval in September of 2004.

We realize that it can be difficult to compare various drogues due to the volume of information about each of them. If you decide to update your website it may help to list the pros and cons of each product and manufacturer separately. That could make it easier for readers and help them understand your own research efforts and opinions more clearly.

I hope this helps. Fiorentino, like any other manufacturer, wants to be sure that information about our products is accurate. We try to ensure that our website has up-to-date and relevant information about our drag devices and other products. We are a small company, but we are willing to answer direct questions if given enough time to do the research necessary for a response. Just let us know what you need and we will work with you on a time-frame.

Sincerely,
Carol Thorp
Fiorentino

[Fi2010]

Originally Posted by thinwater

I contacted the main ones - no point in naming names - and got no response on the issue. Seabrake says minimal stretch. All of the others specify nylon lines, though by implication the JSD suggests no stretch (they do allow high-tech lines and one of the stated virtues is more immediate braking).

It seems they are not at ease making statements by e-mail or on-line about the behavior of drogues in wild weather. Clearly they must have policies against responding to forums, as many companies do. So we post the data we have, we guess and, we share experience.

Thinwater,

We did respond to your e-mail explaining how we would get back to you and here we are. We are a small company and while we try to keep up with blog requests in a timely manner, sometimes the press of business slows us down.

In answer to your stretch vs. non-stretch question, Fiorentino preaches “no slack” in the rode system leading to the para-anchor or drogue. This is achieved by using shorter lengths of rope and/or by adding weight next to the drag device. This information is available in some of Zack Smith’s online videos and at his drag device seminars conducted throughout the country.

Here’s something else that might be helpful. Practical Sailor did a great job citing Zack’s Rode Length and Continuous Rode Tension Formulas in their February 2009 issue:


“Smith maintains that rode tension is the ‘big secret’ in successfully using and sizing a parachute sea anchor. ‘Rode naturally stretches under force until it becomes taut. As force is reduced, rode becomes relaxed,’ Smith wrote us. ‘What we want to avoid is too long a period of rode slack because this leaves a vessel-swinging beam to, where waves can heavily roll the boat or in rare circumstances, cause it to fall back on the rudder(s).’

One way to get and maintain more rode tension is to deploy a larger anchor; however, this also makes retrieving the anchor more difficult. In order to get more tension out of a smaller anchor, Smith suggests paying out shorter lengths of rode, adding a small length of chain next to the parachute, or flying a riding sail to increase vessel windage.”

In reference to nylon versus other non-stretch fibers, Fiorentino mixes the two because it maintains rode strength, but still provides some stretch in the event of shock loads. Currently, Fiorentino is the only manufacturer that takes this approach with deployment rode. This information on rope mixture has been readily available on Fiorentino’s website for many years.

Sincerely
Carol Thorp
Fiorentino

[thinwater]

Originally Posted by Fiorentino

Thinwater,

We did respond to your e-mail explaining how we would get back to you and here we are. We are a small company and while we try to keep up with blog requests in a timely manner, sometimes the press of business slows us down.

In answer to your stretch vs. non-stretch question, Fiorentino preaches “no slack” in the rode system leading to the para-anchor or drogue. This is achieved by using shorter lengths of rope and/or by adding weight next to the drag device. This information is available in some of Zack Smith’s online videos and at his drag device seminars conducted throughout the country.

Here’s something else that might be helpful. Practical Sailor did a great job citing Zack’s Rode Length and Continuous Rode Tension Formulas in their February 2009 issue:


“Smith maintains that rode tension is the ‘big secret’ in successfully using and sizing a parachute sea anchor. ‘Rode naturally stretches under force until it becomes taut. As force is reduced, rode becomes relaxed,’ Smith wrote us. ‘What we want to avoid is too long a period of rode slack because this leaves a vessel-swinging beam to, where waves can heavily roll the boat or in rare circumstances, cause it to fall back on the rudder(s).’

One way to get and maintain more rode tension is to deploy a larger anchor; however, this also makes retrieving the anchor more difficult. In order to get more tension out of a smaller anchor, Smith suggests paying out shorter lengths of rode, adding a small length of chain next to the parachute, or flying a riding sail to increase vessel windage.”

In reference to nylon versus other non-stretch fibers, Fiorentino mixes the two because it maintains rode strength, but still provides some stretch in the event of shock loads. Currently, Fiorentino is the only manufacturer that takes this approach with deployment rode. This information on rope mixture has been readily available on Fiorentino’s website for many years.

Sincerely
Carol Thorp
Fiorentino

Second, I thought I had made it clear that, in my mind, the products are different but that calling one better or worse was beyond my expereince or the data. I expressed some ideas specific to my particular boat - no more than that. My initial intention was only to compare drag vs. speed data; thread comments grew beyond that - as they so often do - but I did make several efforts to bring the thread back on-topic, which was solely to create some comparable data.

Let me re-state; I my data was never intended to say which is best, only to compare the drag data for different units. I hope all of the readers understand this. Since I am not aware of any data base that allows a buyer any reasonable means of comparison, and because manufacture web sites lack this sort of data, I took an experimental approach and openly comparable quantitative invited drag data.

Thank you for the rode discussion. I think it fits well with discussion about limiting slack and stretch. Always a compromise.

Question. You seem to be responding about rodes for parachute anchors (comments about be thrown back on the rudder - a parachute anchor risk). The question was actually targeted at the Small Shark. Is the answer the same?

[thinwater]

Originally Posted by Fiorentino

Hi Thinwater,

Sorry it took us awhile to get back to you, but we wanted to take time to go through your material. Fiorentino has now reviewed your personal blog site (sail-delmarva) which describes your tow test and some of the sources cited in your extrapolation of data. Per your e-mail request, we are posting our conclusions to this forum.

As you note, you used multiple sources to extrapolate data. This can be tricky at times as sources can be mixed-up or information misstated. I think this is what led to misquotes about several manufacturers’ products, including the company I represent.

For example, you state that you have extrapolated information about the Delta, Gale Rider and Shark drogues and say that they are steering assistance devices rather than slowing devices. Our response is that all three are designed not only for steering, but as speed limiting drogues intended to slow the boat. Shark tests completed by Fiorentino show it is highly effective in slowing boats in heavy seas.

Using proper weights to sink drogues is an important issue for boaters. The Seabrake, which you mention positively in your post, uses a long length of chain to sink it properly. Other drogues use the same technique. These long lengths of chain can be difficult to deploy in rough weather and are nearly impossible to retrieve without banging your boat’s hull. Fiorentino designed the Shark with a Drogue Tail so a mushroom anchor can be used to sink the drogue thus eliminating the need for chain. The “Sail” magazine article that you reference actually gives kudos to this feature plus the Shark’s ease of use.

Because of your interest in data, you may want to take a look at a drag test that Fiorentino’s Zack Smith (drag device inventor) managed with Steve Dashew (author). Check out Dashew’s drogue report at SetSail » Blog Archive » Drogue Testing. Evans Starzinger and Beth Leonard also attended the drag test.

In an effort to support your test results you quote data from the “What a Drag” comparison article by Kimball Livingston. We are familiar with this “Sail” magazine article at Fiorentino and feel some significant points have been overlooked in relation to the Seabrake. For example:


The Seabrake tested was actually a GP30L a larger model than the GP24L. Livingston made mention of this misprint, clarifying how the GP30L is sized for vessels 36-55 feet and not for boats to 35 feet like the GP24L. We bring this to your attention because this makes your “comparison between units” inaccurate.

There was a very strong and fluctuating current present during the “Sail” drag test compared to your tow test. Tidal currents can dramatically affect test results.

The Seabrake was not rated better over any other drogue in the article as you indicate on your website.

The Seabrake is a speed-limiting drogue like the Delta, Galerider, & Shark. It does not belong in its own separate category as you suggest, nor is it similar to the Series Drogue.

The Seabrake lost its SOLAS approval in September of 2004.

We realize that it can be difficult to compare various drogues due to the volume of information about each of them. If you decide to update your website it may help to list the pros and cons of each product and manufacturer separately. That could make it easier for readers and help them understand your own research efforts and opinions more clearly.

I hope this helps. Fiorentino, like any other manufacturer, wants to be sure that information about our products is accurate. We try to ensure that our website has up-to-date and relevant information about our drag devices and other products. We are a small company, but we are willing to answer direct questions if given enough time to do the research necessary for a response. Just let us know what you need and we will work with you on a time-frame.

Sincerely,
Carol Thorp
Fiorentino

First, I made some manner of dislaimer or limiting statement in nearly every post. I only posted data where there seemed to be a vacuum. Nearly every published test I found is short on force data. I think that is very odd. I invited quantitative data.

The JSD data came from Coast Guard test, not the Sail test. The JSD data was self-generated. The Sail data was not used for comparison purposes, because I noticed a significant discrepancy. The misprint explains it - I did not know that. However, I do not have reason to believe my data is basically wrong or to revise it, in the absence of other data.

The link you suggested shows the Gale Rider and Small Shark as similar, and the JSD as being a higher drag devise. A 1.6-knot difference may seem small, but it represents an enormous difference in force at an equal speed.

Your polyester/nylon rode answer seems very reasonable to me. Climbing ropes have use composite construction for many years, because it allows low/moderate stretch under light loads, and more controlled stretch under higher loads. It is to limit the bungee effect, as you have noted. Yes, I saw the information on your web site and that is why I thought your explanation would be both interesting and enlightening.

Retrieving chain is less difficult on a catamaran, that is all that I am personally interested in, and I have sated as much. I'm not truly working on the transom, and that is one of their strengths. They have weaknesses. I agree, though, that attaching weight to the back of the drogue has advantages. I am also impressed by the rugged construction of the Small Shark and the impressive braking force from a small package. An excellent design.

Much of my post was centered on the Seabrake, because I have one, wanted to learn about its nature, and to consider its application on my 32-foot catamaran - not because I believe it is best. I have found the process very educational. I will revise my blog to reflect your input.

[Fi2010]

Thinwater,

Yes, Fiorentino’s rode length and continuous rode tension formulas apply to the Shark drogue.

Tests conducted by Fiorentino indicate that the average length of rode to use with the Shark is 150 feet for gale strength weather and 300 feet for storms. For extreme weather, Fiorentino suggests ten feet of rode for every foot of boat. We believe in deploying shorter lengths of rode combined with a small anchor and small length of chain (if necessary) or flying a riding sail to increase vessel windage as mentioned in an earlier response to you.

Readers should be aware that these formulas were developed and tested for Fiorentino products. Although we believe they may work with other brand name products, our formulas are controversial. Presently, all other sources promote traditional theories on drag device deployment, including longer rode lengths, ending with mixed results.

Although our drag device developer Zack Smith has been lecturing about these shorter rode formulas (Zack’s Big Secret) for the last decade at boat shows and at his seminars on drag devices, it wasn’t until “Practical Sailor” cited his work in its February 2009 issue that we received media attention on the subject. For this reason Fiorentino is preparing to release data later this year that lends support to and discusses the pros and cons of Zack’s theories on rode length and continuous rode tension.

Fiorentino’s Load Cell Tests

I managed to catch Zack before his departure to the Oakland Boat Show. I asked him for a comment on your load cell question for this blog. Here’s what he said:

“Fiorentino’s average load cell readouts indicate 400 pounds of force is applied to your vessel when towing a small Shark. Shock loads have been recorded as high as 550 pounds. Fiorentino projects forces could potentially reach 2,200 pounds in severe weather.”

Although the world of parachute sea anchor and drogues can lend to some complexity from time to time, we hope for now, we have satisfied your questions and appreciate your invitation to join in this important discussion.


Thank you
Carol Thorp
Fiorentino