Being a safe boater is really quite simple. All you have to do is have an answer for the question, “What if?”

Most conscientious boaters do a pretty good job with the big “what ifs”: What if someone falls overboard? What if there is
a fire?

It’s lacking an answer for the less-obvious “what ifs” that has gotten more than one boater into trouble.

Today’s modern, long-distance power cruising gives us the means and reliability to explore distant islands and harbors. But every time we go out, we are still placing ourselves at the mercy of Mother Nature—a force capable of challenging the seasoned crew and most stoutly built vessel. Only when you’ve determined what you would do in any “what if” scenario are you truly safe handling your passagemaker.

As a longtime training and delivery captain, and owner of my own long-range cruiser, I believe there are two pieces of safety equipment that do not receive their due attention. Far too few boats carry them, too: the speed-limiting storm drogue and the sea anchor.

Often confused as the same piece of equipment, a speed-limiting storm drogue and a sea anchor serve two different purposes. Both are typically made of high-strength nylon or Dacron, and are conical or parachute-like in shape and design. They are both designed to stay open to oncoming water and resist the water’s exit to create drag.

But this is where the similarities end.

The Storm Drogue

A storm drogue is a device towed submerged from the stern to limit (but not stop) the boat’s speed, and to keep the vessel’s stern at a set angle to following seas. Conversely, a sea anchor is a device deployed from the bow to stop the boat’s movement through the water, and to keep the boat’s bow into oncoming waves. These devices are not interchangeable, nor will one device serve both functions.

The use of a drogue is relatively well known in the sailing community as a steering device in the event of a lost rudder, but drogues can have an equally important application on a power cruising boat. Mariners have known for centuries that dragging something from the stern will slow the boat and keep its stern square to the waves (the word “drogue” is believed to be a derivation of the word “drag”).

Trawlers with a displacement hull and nonsubmerged transoms handle a following sea quite well by allowing waves traveling faster than the boat to pass under the hull without pushing it considerably faster, or pushing the stern sideways. However, if those seas build enough, they can cause the boat to increase to an uncontrollable speed, or, worse, cause it to broach. The only way to stop this is to limit the speed of the boat and gain some directional stability from the stern.

This is where the drogue comes into play. A properly designed device dragged from the stern not only will slow the boat, but also will help resist the yawing movement that can end in broaching. While all drogues available today aim to achieve the same result, they do so through a variety of designs and materials. Most are fabric with an opening to allow water in, while restricting the water’s exit, creating resistance in the process.

Once deployed, the storm drogue reduces boat speed down the wave face, keeping the boat heading straight “downhill” instead of letting it get pushed or pivoted beam-to the following seas, risking a broach. This technique could be most helpful when entering an inlet, where following waves can build to deceivingly steep sizes.

Drogues must be securely attached to the boat. Ideally, the drogue is attached to multiple points on the stern, centering it on the transom by way of a bridle. If the two lines securing it to the boat have a block on one line and a fixed point on the other, you can move the drogue line from one side of the stern to the other, like the traveler on a sailboat’s boom. This setup can assist in keeping the stern square to a quartering sea and could be especially useful maintaining steerage when entering an inlet with a following sea on your stern quarter.

You likely won’t be in the calmest of conditions when deploying a drogue, so it needs to be easy to attach, deploy and retrieve. Having a setup ready to send overboard in a single package is the best scenario.

The control and stability provided by a drogue can be a lifesaver, but what happens when slowing down isn’t enough? What if you need to come to a complete stop and the water is too deep to anchor? Or, what if you lose power in tall seas?

The Sea Anchor

Most powerboats without propulsion or the ability to steer the bow into the waves will naturally turn their beam to the wind and waves. At the very least, this is uncomfortable in moderate waves. It’s dangerous in significant seas.

The answer to all of these scenarios is the sea anchor. The most effective sea anchor resembles a parachute, which, when submerged, traps large volumes of water. It creates resistance to the vessel’s movement. With a sea anchor deployed from the bow on a long line (approximately three to four times the boat’s length), the anchor exhibits drag in the water while the wind and waves are trying to push the boat sideways. When attached to a sturdy point at the bow, the sea anchor keeps the bow into the wind and waves. It can also reduce movement across ground to a near stop. This could be crucial with a loss of power near shore, and with wind and waves pushing the boat toward land.

Several manufacturers produce high-quality versions of these devices. Typically, they have ratings for different-size vessels and correspondingly sized drogues or sea anchors. Some rate by vessel length. Others rate by displacement. Some use a combination of both.

Numerous accounts exist of drogues and sea anchors saving vessels and, possibly, lives. If you are planning any extended passages, whether coastal or transoceanic, be prepared for two more “what ifs” by carrying a storm drogue and sea anchor aboard.  

Features of a Properly Designed Storm Drogue or Sea Anchor

• It must open on deployment, and stay open.

• The hardware must withstand high loads while maintaining shape and points of attachment.

• It must stay submerged below the surface.

• It must resist spinning in the water, which stresses and weakens the towline. Swivel devices can be placed in line to accommodate this, but they can also make the assembly weaker.

• It must be towed on a line long enough for it to be pulled through the water at a constant depth, and not be affected by the boat’s rising and falling with the waves. This is typically a line at least three times the boat length. To stay submerged, most drogues are weighted by a length of chain, by weights or by a small mushroom anchor attached to the end of the drogue.

This article was originally published in the October 2023 issue.