Heavy Weather Strategies When Sailing a Catamaran

By their nature, larger catamarans are exceptionally safe offshore. It is not unusual to sail through mildly uncomfortable conditions, such as a gale, only to arrive in port and hear sailors on keelboats talk of “surviving” horrendous weather. A large modern catamaran has plenty of buoyancy and exceptional roll inertia. Together these make a capsize, or inversion, highly unlikely. A 30-foot breaking wave hitting a cat abeam will simply make the boat surf sideways.

On most offshore passages, advanced communications and weather information should preclude you from ever experiencing true gale or survival conditions. The highest risks are run on passages sailed on a north-south axis between seasons. Early spring or late autumn passages between New England and the Caribbean, in eastern Atlantic waters off Europe, or on routes between the South Pacific and New Zealand are where you typically have a chance of experiencing a good wallop offshore. Follow the wisdom outlined in Jimmy Cornell’s World Cruising Routes, and these risks should be minimized. Regardless, anyone venturing offshore in a multihull should be prepared to handle the worst.

All cats are not the same

Cruising catamarans today roughly fall into two categories. Charter/cruising cats: Production catamarans built for the charter market typically feature integrated fixed keels, shoal-draft low-aspect rudders, high-windage flybridges, masts located well forward, shorter bows and heavier displacements. Even in ideal flat-water conditions, some of these boats will struggle to make significant progress to windward and typically sail close-hauled at 55-60 degree true wind angles (TWA). Heavy-weather strategies on these types of catamarans should focus on maintaining control and achieving a moderate speed without endangering boat or crew.

High-performance cruising cats: High-performance cruising catamarans typically have efficient daggerboards or centerboards, deeper rudders, less windage and less displacement. They can go to windward at a 45-50 degree TWA in nearly all conditions. A performance cruising catamaran can typically outsail even the best keelboats to windward. Given their light weight and ample sail plans, attention must be paid to sail selection to remain safe in all conditions. Strategies for managing storm conditions should focus on higher speeds, lower loads and balance.

Some catamarans are not easily categorized within these two groups, and strategies for handling them will vary and should be noted. You need to make a frank assessment of your own boat before venturing offshore. The boat’s manufacturer should also give you a sail-selection chart specifying safe sail limits for any conditions. If no such guide exists, a simple heeling gauge may be helpful.

Specifically, most cats are happy and safe sailing at 6-7 degrees of heel as measured in flat water, or on the trough of a wave. As the boat approaches 10 degrees of heel, the windward hull will be close to lifting. It is safe to say that a cat should not lift its weather hull while on a cruising passage!

As you’re sailing your cat, you should ask yourself a few critical questions. Do your bows dig into the waves when sailing upwind? Do your bows press down when sailing fast downwind? Is your bridgedeck high enough to stay clear of the water sailing upwind in a confused sea? Rough weather will soon reveal any shortcomings. Plan to make use of your catamaran’s strengths and to minimize its weaknesses

Storm tactics

Sea room is the first consideration that will determine your tactics for the given conditions. Are you in open water and able to sail around the conditions? Or are you sailing along a coast with limited room to leeward?

The charter cat: If you have limited sea room, then you need to set up your catamaran to make headway to windward. Most cats built for the charter market have only one headsail, a roller furling genoa, which will be of limited use in storm conditions. On such a boat the heavy weather sailplan may be limited to a reefed mainsail. When sailing under deeply reefed main alone, the traveler should be eased down several feet from centerline to create enough drive to let you make headway. You can monitor your course over ground on the GPS and also use visual bearings (if close to shore) to track your progress.

Check your helm balance. If the autopilot is struggling, with the rudders indicating several degrees of weather helm, ease the mainsheet to induce more twist in the leech. This will take the strain off the pilot. If the helm is neutral, the mainsheet can be sheeted in harder. The goal is to make forward progress without enduring leeway. You should be able to achieve a comfortable, leisurely pace of 5-7 knots in nearly all conditions. If the sea state makes this difficult, run the leeward engine to make better progress to windward.

The performance cat: A performance cat will have an easier time getting off a lee shore. If conditions are severe, it’s safer to raise the leeward daggerboard and sail solely on the one to windward. That way if the boat gets overpowered and the weather hull starts to lift, the board will lose grip and the cat will sideslip, rather than continuing to heel more. On daggerboard boats, you will need to balance the helm. Many daggerboard cats require an inner forestay carrying a storm jib or staysail to achieve this, although a deeply reefed main will suffice if the daggerboards are not positioned too far forward. Again, experiment on your boat to see how she likes to be set up. As with charter cats, the boat will sail well under main alone if the traveler is dropped down a few feet and the leech is trimmed for helm balance.

A centerboard catamaran handles much like the daggerboard cat, except that you can trim the mainsail for performance and alter the centerboard angle to balance the helm.

Many of today’s performance catamarans can sail at up to 14 knots to windward in ideal conditions. In gale conditions, the ride should be comfortable and safe in the 7-9 knot speed range. Slowing down is easier on the boat, and is certainly easier on the crew.

Storm Strategy

If your desired course puts you on a beam reach, you need to make a decision. Nothing puts a greater load on a catamaran than a breaking wave on the beam. While nearly every catamaran is engineered to CE Class A-1 codes for open water, a 90-degree impact from a wall of water hitting a cat’s slab sides and large windows will put your boat at maximum risk. Choose a course that puts the waves and wind ahead or aft of the beam.

If you know which way the wind will shift, then you can make better decisions. For example, if you know you will be headed during a passage, perhaps you should aim above your course to start. If you will be lifted over the course of the passage, aim low. I repeat, no matter what you choose to do, avoid beam-on seas! Your cat will absorb impacts much better if they are not at a right angle to your course.

Sail combinations will be similar to those mentioned above, with the traveler set farther to leeward. Pay attention to heel angle. It is difficult and slow to steer your way out of a squall on a beam reach. When in doubt, take in another reef, and don’t be in a hurry to shake those reefs out even if you sense the wind is moderating. If your cat has boards, keep the leeward board up, and the weather board down. Keep a close eye on helm balance and adjust your mainsheet accordingly to achieve balance.

Most gale conditions are forecast well in advance. The knowledgeable sailor will position their catamaran to avoid them or will at least be able to sail on the back-side or downwind quadrant of low-pressure systems. Once you have learned your boat and experienced a gale or two, sailing in these conditions may soon provoke some of your fondest sailing memories.

When the going gets tough

On a charter-type cat, the shallow low-aspect rudders are frequently in the turbulent flow of water under the hull. Do not expect them to give you a firm grip or a crisp steering response. Steep and confused seas can be a challenge for this type of cat. To a certain extent more speed helps, but the ultimate goal in storm conditions is to keep the bows from digging into the next wave up ahead and the transoms from being broached by bigger breaking waves approaching from astern.

Utilizing warps can be a very effective strategy. There are various ways of doing this. A warp can be dragged in a big loop with the ends secured at each transom, or one can be trailed from each transom, and the lengths varied to help balance the rudders. A longer warp trailed from the leeward transom, for example, can minimize weather helm. Or you could rig a bridle that allows you to adjust the position of a single longer warp from side to side. The goal is to hold the transoms somewhat into the wind and prevent the cat from spinning out in bigger breaking waves. The length of the warp(s) should be set to achieve the ideal boat speed within the wave pattern to keep decent speeds of 6-12 knots, while preventing those terrific surfs into the next wave that can lead to green water on the deck forward.

As for storm sails, these can vary greatly from boat to boat. In general, if the cat has a flybridge with a high boom, you should get the mainsail down early and focus on using your jibs. The most comfortable course will be straight down the wave train, but many jibs will gybe back and forth continually, wearing out both the sail and the crew’s nerves. To stop the unsettling racket try rigging an outboard lead. Otherwise, you may need to head up on more of a broad reach to keep the jib stable.

On a performance cat, you can raise both boards and experience perhaps the greatest days of your sailing life. Speed is your friend. A modern performance cat’s bows will rise as she gains speed, and there are no downsides to going faster. The closer you sail to the wave train’s speed, the smoother the ride becomes, and the less chance you have of experiencing a large wave impact. The sail selection can be a deeply reefed mainsail or a jib sheeted to the outboard rail. Even in 50-60 knots of wind, the ride will be smooth and comfortable as you sail at 15-25 knots. Always check helm balance to keep the rudders and pilots lightly loaded.

The catamaran is a legitimate offshore cruising and voyaging choice. As many converts have already told you, cats are simply more comfortable offshore and handled correctly, their safety record is excellent. Safe passages!

How To Park Your Cat

“Parking the Cat” is an effective method for stopping anywhere and holding your ground, much like heaving-to in a monohull. Cam Lewis parked his mega-cat, Explorer, off Cape Horn in a 70-knot storm to allow a hurricane to pass through during his epic inaugural Jules Verne record attempt. To park, deep-reef your main, drop the traveler all the way to leeward, and sheet the mainsheet hard in. If you have boards, pull them halfway up, then secure your helm so the rudders are pushing the boat into the wind. The cat will sit on a safe, close-hauled course, drifting sideways at approximately ½ knot. If you need a break from pounding to windward, or need to wait for daylight to approach your destination, parking can be an effective strategy. The motion is so smooth while parked that many utilize this strategy for performing repairs while at sea in all conditions. Your catamaran will feel like a big tennis court amidst the maelstrom.

Illustrations by Dick Everitt,

Photos courtesy of Lindsay Turvey