Drag Devices
(Published in Ocean Navigator magazine, Issue No. 70)
Copyright, 1995,
Ocean Navigator, all rights reserved
by Earl R. Hinz
There is something spooky about the two worst sailboat disasters in modern history. They have a unique antipodal relationship and were caused by almost identical weather phenomena: rapidly moving and quickly deepening low pressure cells which could be neither circumvented nor outrun by slow-moving sailboats.
In both storms, the winds reached upwards of 70 knots (Beaufort force 12) and seas grew to 35 feet, frequently breaking due to the rapidity of the storm's onset.
Weather services tracked the formation of these storms, but failed to appreciate their rapid development in time to warn either fleet of the impending gale winds and worse. If that weren't enough, both fleets suffered from inadequate emergency resources on board the boats, which in the end, had to depend on public air-sea rescue services to get them out of their predicament. But there the commonality seems to end and significant differences begin.
The Fastnet Race disaster of August 1979 involved a fleet of 303 racing sailboats, all monohulls and many state-of-the-art for that time period. They met technical qualifications for offshore racing and the crews were generally experienced. In this tragedy, 24 boats either sank or were abandoned and 15 lives were lost. Most of the casualties resulted from abandoning the boats in favor of life rafts, a practice now believed more hazardous than staying with the boat.
The record of the Fastnet tragedy indicates that only one drag device was used in this emergency and the boat using it survived. Most of the reasons for abandoning the boats-dismastings, loss of rudders, capsizing, and intolerable motion below decks, are conditions that can usually be alleviated through the use of a properly designed and manufactured drag device.
The Queen's Birthday Storm of June 1994 (the British queen's birthday is in early June, hence the relationship) involved a cruising fleet of 35 boats voyaging from Auckland, New Zealand, to Nuku'alofa, Tonga, on an annual cruising pilgrimage (another 35-boat section of the same fleet did not get involved with the storm because it was on a different schedule). In this storm, one boat was lost with all three crew; only its empty life raft carrying an activated EPIRB was ever located. Seven other boats were eventually abandoned, but the crews stayed with them until rescue vessels arrived, possibly a lesson learned from the Fastnet disaster. (One of those seven boats was found afloat six months later and salvaged.) Twenty-one crew from the seven boats were rescued directly by surface vessels who responded in a very timely fashion to both EPIRB signals and requests for assistance from New Zealand authorities.
In the aftermath of the Queen's Birthday Storm, it again appeared that drag devices properly deployed might have provided useful insurance for storm survival. Three boats did deploy drogues of a sort and one made a jib into a sea anchor. These helped, but they suffered from improper rigging and the crew's general inexperience with mastering storm conditions. One boat, not abandoned, rigged a professionally made drogue and successfully rode out the storm.
Tactics for storm sailing
We can, and probably will for decades, debate the merits of various storm tactics. They are dependent on so many variables, from boat to crew to weather, that there is no single answer as to which is best. There is, however, a logical and proven progression of decisions a skipper must make when heavy weather is threatening. They involve the anticipated severity of the storm, the preparation of the boat, the condition of the crew, and the availability of storm-sailing gear. Bending on storm sails before the storm hits is the first priority, along with clearing the boat and preparing the crew for a stint of heavy-weather sailing. In most cases this will suffice for the duration of a blow in a well-found boat with capable crew.
While the crew is fresh, the skipper may want to forereach with reduced sail area and continue making distance to his or her destination. Should the storm persist or grow in severity, the captain must decide whether to continue sailing or take passive measures such as heaving to or lying ahull. Both techniques were well proven by early cruisers, but boat designs have changed radically in the past few decades and not many modern cruising boats will do either to the complete satisfaction of the crew.
From experiences in the Fastnet and Queen's Birthday storms we known that heaving-to is questionable in strong gales and also that most modern boats do not heave to in a safe fashion. Nor do many crews know how to heave-to in heavy weather. We also know from both of the storms that lying ahull is just delaying disaster. Sooner or later the boat will be rolled, pitchpoled, and/or pooped beyond her ability or that of the crew to survive.
Heaving to or lying ahull when the waves reach or exceed one beam width in height is courting disaster. Besides, most skippers would prefer to maintain active control of their boats as long as possible into the storm, hopefully, right through it.
When whole gale winds of Beaufort force 10 develop, there appears to be only three viable storm survival tactics: 1) running under control with a unitary (single-element) drogue, 2) running under the stabilizing control of a series drogue, or 3) riding to a proper sea anchor.
A modern boat's powerful rudder can offer excellent downwind control in a storm. Under much-reduced sail (even bare poles) and with a good helmsman on the job, it can be a safe and exhilarating point of sail. But there comes a time when the boat's speed gets too high for positive control; then it is time to think about slowing the boat down and that is the job of the drogue.
The proper speed for a boat running with a drogue is slow enough so that it doesn't surf and fast enough so that when a rolling greybeard comes up astern, it doesn't impact the boat at full strength and cause it to broach. A racing crew in a well-found boat with a powerful rudder can ride the crest of a wave and surf to their heart's content until, possibly, a rogue crest comes along and causes the boat to broach. Cruising boats should hold their speed to less than half of the wave crest's speed but not less than that which provides good rudder control. Remember that, in most cases, cruisers have neither the skills nor numbers in their crews to take advantage of downwind running in a storm.
The best speed for a boat running in heavy weather with a drogue deployed is something a capable helmsman can feel. The boat reacts with a rhythm of life all its own and the crew has a sense of security and confidence in its movement. But eventually even macho determination may be challenged and the whitening knuckles of the helmsman will signal that it is time to slow the boat down. Fortunately, most storms do not have that intensity nor duration, but if they do, then some other solution must be sought.
When storm-force or hurricane-force winds develop (it is possible to have hurricane-force winds without the rotational motion of a hurricane; witness both the Fastnet and Queen's Birthday storms), serious consideration should be given to the deployment of a series drogue or a sea anchor. Both have proven their merits in such applications and the choice of which to take along (if not both) must be made by the skipper before shoving off on his or her blue-water venture.
In using the series drogue and the sea anchor, the vessel is put at the mercy of the seas and the benevolence of the drag device. While a sea anchor can be deployed over the bow using much of the same equipment as used for ground anchoring, the deployment of the series drogue requires prior consideration of building strong attachment points into the boat's stern quarters. It should also be noted that the sterns of contemporary boats are not designed to withstand the full onslaught of storm waves. In this regard transom sterns are the worst designs for handling overtaking seas, with canoe sterns tending to be better.
Drag device use
Proper drag devices can spell the difference between riding out a major storm in relative comfort or laying yourself open to possible disaster in the heavy seas. Viewed as insurance policies when the chips are down, they can help save the boat and lives. The key to success is having the proper device aboard and knowing how to use it. Most failures of drag devices to perform properly can be traced to misapplications. It is essential that the skipper knows beforehand the differences between drag devices and how they are used.
We are talking about only two generic drag devices: the drogue and the sea anchor. They have only one thing in common: they add drag to the boat. But the way of using that drag for storm survival is the difference between success and failure. Marine literature abounds with stories of the improper use of drag devices. One result of this is that these devices have been damned by many writers. It is the writing that should be damned, not the device. To continue to quote from the experiences of Voss, Hiscock, Smeeton, Moitessier, et al, is to ignore the fact that in their day they did not have access to well-developed and tested drag devices. Further, their boats and their seamanship skills were far different from those of today's sailors.
A drogue is a drag device much smaller than a sea anchor. Deployed over the stern of a boat, a drogue is intended only to slow the boat down, not to stop it. The drogue is useful when the boat is running downwind and has plenty of sea room. The size of a drogue and its resulting drag are normally less than that of a sea anchor and its design is markedly different. (Note that the drag of the series drogue deployed from the stern can be as high as that of a sea anchor, but considerable forward motion of the boat is required to develop that much drag.)
A proper sea anchor is a large parachute-like device deployed over the bow of the boat to stop it in the water. It is the water corollary to a ground anchor. A device posing as a sea anchor that is not large, strong, and powerful enough to hold the bow of the boat into the wind and waves is an impostor. The sea anchor must be large enough to prevent the bow of the boat from falling off and the hull from lying broadside to the waves as in lying ahull. A boat riding to a sea anchor experiences some leeward (backward) drift depending on the relative size of the sea anchor and boat and the fury of the storm.
Modern drogue designs
Drogues in the early days were makeshift devices such as tires (carried for use as fenders), a set of oars lashed together and weighted to submerge, rope warps deployed in a loop or strung out with an anchor at the ends, or even a submerged dinghy. Such jury-rigged devices did not and could not be expected to have adequate or consistent performance under severe weather conditions. It was stories stemming from their (mis)use that clouded the early acceptance of drogues as a safety device.
Many drogue designs have been tried over the years. To be successful, a drogue has to have consistent performance and stability and a proven durability to last out the storm. It must also be easy to handle under the adverse conditions presented by a storm. Not until serious drogue research was initiated by responsible persons and agencies did the offshore sailboat have access to a product on which it could depend for survival in severe storms. Now we have a number of successful designs available, and, as with ground anchors, the variety is such that they support endless discussions on which one is best. The one thing they have in common is that they do enable a boat to run safely with a storm.
Drogues can be classified as either soft or hard designs, depending on whether they are made of fabric-like materials or wood, metal, and plastic. Two of the more recent hard designs are the British Attenborough Sea Drogue, based on the minesweeping paravane principle and the Australian hard plastic Seabrake (HSD 12).
From the boat operator's viewpoint, the "hard" drogue designs have drawbacks in handling in limited cockpit space, as well as in stowage. Within the confines of most blue-water boats there is little space for equipment that cannot be folded, rolled, or stuffed into a soft bag. Hard drogues are, therefore, not very popular on recreational boats.
Drogues made of soft (fabric) material have become the norm in contemporary blue-water boats. They are durable and easy to stow. Among the current crop of available drogues are the following:
The first four are unitary drogues with a single drag-producing element at the end of a long tether. The fifth has drag cones distributed along most of the length of the tether.
The modern sea anchor
Naval architects have designed boats with the proper lines, contours, and strength at the bow to cleave the oncoming seas, and it is from there that all anchoring should be done. No part of a properly designed boat is stronger than the bow, nor is the boat motion expected to be comfortable when riding to wind and wave coming from any direction but forward.
In essence, all of today's sea anchors look somewhat like an airman's parachute when in use and, in fact, some are parachutes. They have sometimes been referred to as hydraulic parachutes. The big difference between the operation of an airman's parachute and a sea anchor is that the airman's parachute allows for a certain rate of descent, close to 15 to 20 feet per second, whereas the sea anchor is designed for zero rate of movement through the water. The latter is easy to obtain since water has 800 times the density of air. Drift of a vessel lying to a proper-size sea anchor will be under one knot. Small, conical-shaped devices advertised as sea anchors should never be thought of for survival use.
Although it is possible to use an airman's parachute as a sea anchor, as many have done in the past, it is probably better for most of us to consider buying one made by a responsible manufacturer just as we buy proven, ready-made ground anchors. The research, development, and testing that a manufacturer has put into his product will assure a more satisfactory result. There are a number of successful sea anchors on the market that have already proven themselves in heavy weather. They are all of the parachute design which seems to be the most satisfactory.
When choosing a sea anchor, err on the side of too large rather than too small. No one size will fit all. The idea that a smaller sea anchor will "give" when the waves impact the boat is patently untrue. The large mass of water entrained in a sea anchor canopy cannot be accelerated fast enough to absorb a wave's impact on the hull. The tether has to take up this shock load. On the other hand, a small sea anchor only lets the boat drift to leeward faster and to yaw into a broaching position. As the sea anchor size is diminished, the boat reacts increasingly as though it is lying ahull. Rapid backward movement of the boat resulting from too small a sea anchor jeopardizes the rudder. Modern boats with a great deal of windage forward ride better to a sea anchor if a riding sail is used to hold the stern downwind.
Sea anchors can solve a variety of problems at sea. The singlehander can lie to a sea anchor simply to rest or make repairs in a moderately quiet environment. A boat whose rudder has failed can be repaired while at rest riding to a sea anchor. A dismasted boat can buy time for making a proper jury-rig to continue sailing. The boat overwhelmed by heavy weather can ride to a proper sea anchor while the crew rests and puts it back in order. The sea anchor is a tool to be used when normal seamanship techniques are inadequate to solve the problem at hand. Whether you think you will ever need one or not, you will find it comforting to know that you have one more weapon in your arsenal of heavy-weather survival gear.
Although some boats still opt for used airman's parachutes as sea anchors, the ability to convert these to durable survival devices is questionable. Good sense suggests that contemporary blue-water boats should only consider contemporary sea anchor designs. The following sea anchors are available:
Perhaps we are not far from the day when every blue-water sailboat, racer or cruiser, will carry a drag device as part of its heavy-weather security blanket, just as every well-equipped boat now carries a life raft and an EPIRB. Blue-water boats must be capable of handling any weather situation that may come along. While none of us would choose to leave the safety of a harbor in the face of storm winds, they can develop along the way and there is nothing to do but battle them out in the best manner possible. Even though you have a sound boat and employ good seamanship, your chances of survival are vastly improved by also carrying a proven drag device.
If in doubt about which drag device to carry on a cruise, the answer is both, because you do not know beforehand which you will need. To get the desired use out of these drag devices, they should be of professional design, tested under severe circumstances, and well made to stand the gaff of 24 to 48 hours of continuous deployment under extreme loads. There are a number of such drag devices available, each costing less than a 406-MHz EPIRB, a life raft, an SSB radio, or a paper insurance policy. In fact, it is possible to buy both a quality drogue and a sea anchor for the price of the other life- saving options.
You can indeed carry both types for the price of one year's paper insurance premium, the latter being unable to contribute to your safety at sea. Although sound seamanship remains the ultimate line of defense, it helps to have on board some modern devices to assist in your seamanship. Do not neglect this real blue-water insurance policy.
There is no one best tactic for heavy-weather survival. You have to choose that tactic which best fits the weather, the boat, and the crew. Your seamanship will be tested to the ultimate in storms, as will your determination to survive; but whatever you do, don't abandon the vessel as long as it is still afloat, the alternatives are far worse. A 1905 seamanship manual says: "Now praying on shipboard is not to be scoffed at, but it should be delayed until man has exhausted every possible means of saving the ship."
Earl R. Hinz, based in Honolulu, writes often on voyaging topics and is the author of the book Understanding Sea Anchors and Drogues, published by Cornell Maritime Press.
(ed.note -- Mahalos to Robert Hettinga for digging this one up)
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