The Database: Purpose & Guiding Principles

If instead of sending the observations of able seamen to able mathematicians on land, the land would send able  mathematicians to sea, it would signify much more to the improvement... of the safety of men's lives on that element.   

Sir Isaac Newton

Pushing Back The Envelope

It was once thought that man could only sail so far before he fell off the edge - "beyond this point there be demons only." Magellan sailed beyond the edge and didn't fall off. It was once thought that man could only fly so fast before he fell off the edge. Chuck Yeager flew faster than the speed of sound and didn't fall off.

These two men succeeded in "pushing back the envelope" - going the limit, and then a little farther. How? Through risk taking, enterprise and courage? Well yes, but there was more to it than that. There was method in the way these two men went about their business. Magellan was well versed in the disciplines of seamanship and knew ships inside out. Yeager was well versed in the principles of flight and knew airplanes inside out.

The forces that generate weather anomalies at sea originate within the thermonuclear mass of the sun. While there is little hope of being able to survive such things as extreme hurricanes and typhoons without some land-born assistance, there is nevertheless a great hope and possibility of being able to push back the envelope of survivability in a Force 10 gale.

We want to enlarge the envelope so that cruising yachts don't "fall off the edge" when the wind rises to Force 10. If we are to succeed we too must avail ourselves of some sort of methodology. Individual courage, individual enterprise and individual seamanship may push back the envelope for one yacht, but unless the lessons learned on that yacht are documented and published they may go to waste. It takes a mutual fund of information to prevent this sort of waste. A database.

We want to push back the envelope for cruising sailboats. This is easier said than done. It varies from boat to boat. It varies from hull shape to hull shape, from keel-type to keel-type, from monohull to multihull. Certain vessels are inherently seaworthy. Others are handicapped the day they roll off the assembly line.

In general, vessels sixty feet and over have more generous envelopes by virtue of their size alone. These bigger boats can push back their limits a little further by means of drag devices. But where sea anchors and drogues can really make a difference seems to be in the 28-48 ft. size range - the class that makes up 90% of the cruising fleet around the world.

While no drag device can make any of these smaller boats fully invincible, the right one deployed at the right time can definitely push back the envelope. For some it may push it back a little. For others a lot. For the majority, however, our goal is to establish a beachhead at the Force 10 mark. No matter, even if a drag device can push the envelope back by a single inch it may make the difference between living to tell the tale or disappearing without a trace.

This fleet of cruising yachts is in need of methodology - a formal database that will contain accurate information about the use of drag devices in heavy weather. An ever-growing resource such as this stands a good chance of pushing back the envelope for the class that took the greatest hit in Fastnet 79, the Queen's Birthday Storm and indeed in every storm in the history of offshore sailing.

We would all like to learn how to push back the envelope on our own cruising boats. But there is a learning curve standing in our way. While there is no substitute for blue water miles and hands-on heavy weather experience, there is much to be said for the process of vicarious learning as well. We can each go out, chase down storms, and try to learn lessons solely on our own. Or we can learn a lesson or two from those who have already been in storms. We can go it alone like Slocum, Voss and Dumas, learning - or perishing - by our own mistakes.

Or, we can learn from the experiences of others.This is the objective of the Drag Device Data Base. The sailors featured in this publication provide the enterprise, the daring, the courage and the "combat experience." The authors provide a method of organizing the information.


In the Footsteps of K. Adlard Coles

Adlard Coles and his era may have passed away, but his legendary masterpiece Heavy Weather Sailing will always be a best seller. What is so remarkable about Heavy Weather Sailing is that in it Coles laid down a foundation for the methodical comparisons of different tactics used by small craft. It was Coles himself who got us off on the right foot. He was an enterprising seaman with many gales under his belt. He knew sailboats inside out. But the ingredient that set his work apart was the methodical way in which he compiled, documented, and analyzed case histories.

Coles avoided dogmatism. He stayed away from second hand accounts, unsubstantiated claims and idle speculation, relying on real life observations, evidence and data instead. He let the facts speak for themselves, searched for compelling logic and was quick to nail it down when he found some. And yet he was in most respects slow to speak from a posture of certainty. He kept his mind open, avoided overcompensation and was willing to learn new lessons. He understood the subject of heavy weather tactics to be complex and did not wish to draw false inferences or jump to conclusions. He purposely left many questions, in particular the one relating to the uses of sea anchor and drogues, open to future resolution.


Statistical Reliability

Someone once said, "testimonials are bad science," implying that they are steeped in emotion and lack the element of dispassionate comparison which is the essence of the scientific process. While it is true that there will always be some degree of subjectivity and exaggeration mixed in with the story of a little boat that has been through a frightening storm at sea, testimony is valuable all the same because it can broaden the base of information. Much of science derives itself from statistics. Indeed quantum mechanics itself uses statistical abstractions to measure probability.

A heavy weather testimonial may be laced with emotion and exaggeration, but it may broaden the base of information nevertheless.

An illustration: A sailor uses a parachute sea anchor in a gale. He is the first sailor in history to have done so. He comes back extolling the virtues of sea anchors. He says it saved his boat and his life. He says "it is the only way to go." What does this testimonial tell us? Maybe not much. Perhaps his boat was a fifty foot steel schooner with significant windage aft and a perfectly symmetrical hull shape. Perhaps he just got lucky or he paid out sixty feet of rode and the waves just happened to be sixty feet from crest to crest.

A second sailor goes out and uses a sea anchor in a gale. He comes back with a negative report. He says, "sea anchors don't work." This testimonial may not tell us much either. Perhaps the sea anchor was too small; his boat was cat-rigged - tremendous windage forward; the keel had some strange configuration to it; he just got unlucky; he paid out two hundred feet of rode and the waves happened to be exactly three hundred feet apart, producing divergence and convergence.

Any arbitrary assessment of these two testimonials is bound to reek of bad science. But just you place them side by side in the same database and suddenly you have the beginnings of good science. You have control mechanisms; there opens up a possibility of a whole range of methodical comparisons.

Place ten documented case histories in the same database and an outline begins to emerge. Increase the number to a hundred, and you begin to see a certain pattern. Three hundred, and now you can all but rule out coincidence and the influence of Lady Luck. Five hundred, and now you have a large number of observations from which general rules can be inferred. Increase it to a thousand, and now you have a statistically reliable tool of heavy weather prognosis.

The DDDB was instituted to do just that - obtain a statistically reliable tool of heavy weather prognosis.

Needless to say, however, it takes a great deal of cooperation and communication to make the DDDB a success. Cooperation and communication among drag device manufacturers, for one thing; among safety experts and magazine editors, for another; most importantly, among cruisers themselves.

Fortunately the advent of the world wide web makes such cooperation and communication a lot easier. Whereas previously the database was published only as a hard-copy book, now manufacturers and safety experts on land and sailors on high seas are able to download from or submit to the database in real time. As a result the mutual fund of knowledge should increase by leaps and bounds.

It is not the authors' intent that the DDDB should ever become a substitute for real seamanship, or that it should ever become a crutch.

From the onset sailors must understand that there is no substitute for individual initiative and self-reliance in a storm - this point cannot be overemphasized. Better to throw the abstractions and the theories away and take full control of one's own situation at sea, than to lean on such things as though they were crutches.

The files in this publication are mere pointers - signposts. The time may very well come when the reader will have to choose his or her own route. If there is a lesson to be learned from the Pardey success story it is this: Never rely on others when you can rely on yourself. By all means study up on the available information. But know this: When the wind rises to Force 10 you must assert yourself against the sea and make unique decisions of your own.

Participation in the DDDB should never compromise individual initiative and self-reliance at sea. Those strong individuals who prefer to keep to themselves need never feel compromised by participating in the DDDB. If they learn an important lesson in a gale they can pass it along anonymously if they wish. There is no individual freedom lost by such participation and everything to be gained by it. Very often it is the rugged individual who is on the cutting edge of the learning experience out there. Indeed the history of seamanship has been written by strong individuals.

Some cooperation is productive - and necessary - among drag device manufacturers. Many years ago Victor Shane persuaded Don Whilldin, president of Para-Tech Engineering, to participate in the DDDB. As a result we now have a wealth of documentation - greater statistical reliability - relating to bow-deployed sea anchors. Many of the case histories in this publication relate to the use of Para-Tech sea anchors. To the skeptic this may come across as conflict of interest. But to those who are "out there doing it," the compilation has always been a treasure trove of useful information.

Para-Tech's participation in the DDDB has been productive in terms of design improvement as well, many Para-Tech improvements being direct results of that participation. Some sailors, for example, had had problems with the wind inflating parachutes on deck. The DDDB feedback that Victor Shane passed on to Don Whilldin resulted in the development of a DSB (deployable stowage bag). One no longer has to take a Para-Tech sea anchor out of the bag. One simply throws the bag into the sea, and the parachute self-deploys from the bag. Another development was the incorporation of a separate recovery bridle for attaching the float line to the parachute vent hole - see File S/P-5.

Other drag device manufacturers have agreed to participate in the DDDB but some have not, preferring to treat the feedback they receive as proprietary. This regrettably reduces the available information. There is an implicit relationship between drag devices and offshore safety. If drag device manufacturers learn something new from their customers, we hope they will publish it, either in the clearing house of the DDDB, or in some other public forum. We can learn much by the mistakes of others, but only if we are made aware of them.

A few of the files contained in the DDDB were derived from books and magazines, the rest from documentation provided by owners and delivery skippers. In each case the standardized DDDB form was used, allowing for observations, opinions, concerns, suggestions and advice. Space does not permit the publication of the actual completed DDDB forms, but the reader can have copies by sending a SASE and requesting the file by designated number (see address below).

In some cases the authors have provided the reader with their own explanation of what may have happened. They have found it necessary to editorialize in this respect, either because they have had additional feedback from the participant in the form of long telephone conversations, or because they have received information from other parties and sources. Irrelevant and personal comments have been omitted, but the authors have tried not to change anything. The facts speak for themselves.

Requests for feedback have been published in the letters to the editor sections of domestic and foreign boating magazines. Safety experts, writers and editors have all been alerted to the ongoing DDDB program. All have been supportive, and many have gone the extra mile to give their vote of confidence in the form of an endorsement. The more people who contribute, the greater the benefit to all sailors.

It is the authors' hope that the Drag Device Data Base will in time yield crucial insights and answer some of the difficult questions raised by Adlard Coles in Heavy Weather Sailing. The pieces of the puzzle are coming together and we may yet see the composite in our own lifetime. It is therefore paramount that sailors with "combat experience" participate. It matters not whether the experience was hum-drum routine or life-and-death sensational. It doesn't matter either if the experience seems to be very similar to a previous report; quite the contrary in fact!The very fact that it confirms some features  or tactics is what makes the report so valuable to future sailors.

Previously the DDDB has included only accounts of storm experiences using drag devices. However, it seems that in doing so we are missing out on some valuable lessons that could be learned about storm survival. So, if you have a storm experience - even if you did not use any kind of drag device - please take a few moments to write it up and send it in to us.

If you are able to comment one what you felt worked, what didn't, and what might have, had you had that option available to you, please do include that in your account.

The important thing is to broaden the statistical base of the information. We need a large number of files from which reliable generalities can be inferred. Participation is in every respect easy and painless. Simply fill out, sign and date the standardized DDDB form. You can do this online here, or you can print out the hardcopy version and send it by snail mail. Or send an email. If you have a handwritten account you can either snail mail it to us, or take a photo of it and email it. Addresses, telephone numbers and other personal information will be kept confidential.

IMPORTANT: In addition to filling out the form a few paragraphs of written feedback are required to create a coherent storyline and put everything in a proper perspective. Queen's English is not necessary, and the feedback need not be typewritten. Longhand is acceptable and in some cases preferable - it allows a sailor to put recollections down on paper while the memory is still fresh. Where were you sailing to when the wind came up? Why was the drag device used? Was deployment easy? How did the boat behave? Any major concerns? Chafe? Divergence and convergence? Any weather anomalies? Thunderstorm activity? Microbursts? Rogue waves? Tidal flows? Currents? Shoals? Include any and all general opinions, observations, suggestions, lessons learned and/or things you would avoid in the future. What about the rate of drift? Was it GPS-confirmed? What about retrieval? Was it easy? Was it difficult?

Participants should "tell it like it was" and never feel that they have to protect anyone. Accuracy is highly desirable, as long as it does not become an obsession. When in doubt about such things as wave lengths, wave periods, depth of water, barometer, etc., simply put down a question mark. When in doubt about latitude and longitude simply write "so many miles west of such and such place." The important thing is to participate so we can broaden the base of information and obtain statistical reliability.

Drag Device Database


It is not possible to replicate heavy weather conditions in a laboratory. There are no "safe storms" to go out and experiment in. It follows that the experiences of those sailors who have used sea anchors and drogues in heavy weather should not be allowed to go to waste. These experiences should be documented and cataloged for the benefit of other sailors. This argument was the driving force behind Heavy Weather Sailing. It is the idea behind the modern Drag Device Data Base (DDDB for short).


  • To establish a more comprehensive methodology and protocol for documenting experiences involving the use of drag devices in heavy weather...
  • To act as a clearing house for such information...
  • To compile, catalog and publish the information so that patterns of predictability can be inferred, among them patterns of risk, patterns of failure, patterns of success - WHAT MORE?

Guiding Principles

  • Beware of subjectivity in filtering the data...
  • Avoid exaggeration...
  • Avoid premature conclusions...
  • Take a cautious approach with respect to determinism, with the understanding that nothing can be taken for granted at sea, and that a tactic that appears to have worked well on a particular vessel in a particular sea state may not be suitable for other vessels in other sea states...
  • Try to keep an open mind in the reading of the data and be willing to learn valuable new lessons, while not losing sight of equally valuable old ones...
  • Attempt to integrate opinion and feedback in such a way that theory can be reconciled with observation...
  • Pursue this objective without prejudice until such a time that the survival envelope of cruising sailboats can be pushed out as far as is humanly possible.

Record Groups

The records of this publication are categorized by drag device and vessel type. For example, monohull sailboats using sea anchors off the bow make up one category of records, monohull sailboats using drogues off the stern make up another. Likewise with the classes of multihulls and powered vessels.

For the purposes of this publication the term sea anchor is taken to mean a drag device used off the bow. Conversely, the term drogue is taken to mean a drag device used off the stern. There may be exceptions to this general rule.

File Parameters

Files are listed and numbered by their two parameters. The first parameter identifies the DRAG DEVICE, while the second identifies the VESSEL TYPE. These two parameters are delimited by a "/" (forward slash). The convention used to identify a file is: DRAG DEVICE / VESSEL TYPE - FILE NUMBER. Parameters are as follows:

S       Sea Anchor (drag device used off the bow).

D     Drogue (drag device used off the stern).

N     No drag device of any kind was used.


M   Monohull (conventional sailboat).

T      Trimaran (triple-hulled sailboat).

C     Catamaran (twin-hulled sailboat).

P       Power (powered vessel, fishing vessel (F/V), pleasure, etc.).

R     Rowing boat (including boats that are paddled).


S/M-7:          File #7 in the records relating to monohulls using sea anchors off the bow.

S/T-3:           File #3 in the records relating to trimarans using sea anchors off the bow.

D/M-5:         File #5 in the records relating to monohulls using drogues off the stern.

D/C-1:          File #1 in the records relating to catamarans using drogues off the stern.


Leave a Reply

Your email address will not be published. Required fields are marked *

Using Parachutes, Sea Anchors and Drogues to Cope with Heavy Weather – Over 130 Documented Case Histories