Anticipating bad weather is, as in any boat, the best way to prepare for a blow, but if you’re caught out, Nigel Irens has some advice specific to cats

YW Cat Sailing Techniques logoWhen discussing how to handle heavy weather in a catamaran we have to accept that there is no one solution that works for all catamarans as the strategy will be very different if sailing a standard, charter-type cat from sailing something more performance-orientated.

A racing boat that also has access to high-quality weather forecasting data should be able to steer clear of potentially dangerous weather by outrunning it. Performance cruisers with fine bows should be able to surf downwind in all but the most extreme weather, often travelling safely at speeds of 20 knots or more for periods of, say, 10-15 seconds.

But in the same conditions a stubbier, bluff-bowed charter catamaran would soon start feeling dangerous if the crew were pushing too hard under these conditions.

Obviously reducing sail is the first response, but as mentioned earlier in this series, shortening a mainsail in downwind conditions is not really possible without turning head to wind, and if the wind and sea-state are rising then the moment to do that safely may already have passed.

An experienced crew will have anticipated the rising wind and reefed the main a few hours back. Shortening sail forward of the mast is a piece of cake by comparison – especially if all it takes is to let the jib fly and roll up some of the area. Getting rid of an asymmetric might be challenging, but at least it won’t be dangerous.

Being caught with too much sail up along with the knowledge that you’ve missed the chance to round up and reef is not very helpful. You’ve inadvertently got into this situation and you’ve obviously still got to think up some way to get out of it.

Reefing the main

Brute force might provide the get-out-of-jail-free solution for reefing a main downwind in worsening conditions. But this might not be possible as the sail will not drop when you release the halyard because it will be pressing hard against the standing rigging. The luff cars will also be under load from the side (which they are not really designed to be).

If you have left it too late to head up safely, brute force may be the only way to get the main down

If you have left it too late to head up safely, brute force may be the only way to get the main down

The best way forward is to leave the mainsail halyard where it is and sheet the main in until it is no longer pressing against the rigging. Some vang load on the boom will be needed because simply easing the sheet will invite the sail to twist so that it is still hard against the rigging.

The next move is to start loading both the luff and clew reef lines that are ready for hauling in the next reef. When they are bar-tight you can try easing a bit of halyard. If the sail moves that’s good news, but it will only fall a short way before the sail is once again draped over the standing rigging.

It’s only by repeating this process as many times as necessary that the exposed mainsail should end up the size you want it to be. It may be hard work, but who cares if you can feel the relief at getting out of this fix.

Rounding up to reef

If the mainsail still refuses to come down your only remaining option may be to round up. Given that conditions have likely worsened, this may not be very appealing, but careful preparation can help to minimise the stress.

First, ensure that the halyard is flaked and ready to go. You will need one person to focus on this job plus someone on the helm at all times as you cannot afford for the bows to fall away midway through the manoeuvre.

Also, make sure that the reef line(s) is ready to be hauled in, although if things have got this bad and you are expecting worse to come, it may be best simply to drop the mainsail and return to your downwind course as quickly as possible.

If turning upwind to reef, roll up the headsail by about two-thirds to stop it flogging and losing control

If turning upwind to reef, roll up the headsail by about two-thirds to stop it flogging and losing control


If you have a spare pair of hands, make sure someone is available to tail the mainsheet as you come into the breeze to prevent the sheet from flogging violently.

Then, if you can, have someone ready to pull the sail down at the luff. Full length battens on car sliders often mean that the mainsail luff forms tubes when it is lowered, which get inflated with the strong wind and prevent the sail from dropping on its own. The sail may need some help to get it down onto the boom. Make sure that the crewmember tasked with this is clipped on properly and braced ready for the round up into the breeze.

Have the leeward engine running – in neutral is fine – just so that you can give a burst of forward drive if required to keep your steerage and help with a quick bear away once the manoeuvre is complete.

Finally, communication is key. Make sure everyone knows exactly what you are doing and when they need to act. The quicker you can carry out the drop the better – it will be noisy when you head up into the breeze.

Planning for the conditions

It may be that reducing sail is in response to a short-lived squall, after which you’ll be able to make sail again, but if this is the beginning of a more serious blow then you need to have planned what to do as conditions worsen.

You could try sailing under bare poles for a while, but this can feel a little awkward as you may surf quite well down a wave then almost lose steerage way in the troughs, so setting a smidgin of jib will probably feel better as it’s no surprise that being pulled along from the front is more likely to improve steerability than simply being pushed by the wind pressure on the transoms and aft bulkhead.

Either way if the wind continues to rise a time might come when you want to forget about progressing and just render the boat safe while reducing the stress and anxiety of the crew by making things comfortable below.

You might want to remove all sails and proceed under engine

You might want to remove all sails and proceed under engine


The usual way to achieve this is to set some kind of sea-anchor or drogue, which is designed to do just that, although advising on the right way to go about this is one of those subjects that offers huge scope for deeply entrenched disagreement.

Sea anchors and drogues

The term ‘sea-anchor’ usually refers to a device with an area big enough to hold the boat almost stationary – usually bows on to the seas – whereas a ‘drogue’ is a device intended to slow the boat’s drift downwind.

The consensus among catamaran sailors seems to be that setting a device from the stern works better than from the bow, so the drogue approach is the obvious choice as a full sea anchor tends to hold the sterns down, increasing the risk of taking a tonne of green water in the cockpit.

There are some neat series drogues available now which consist of a strong line with multiple tiny drogues attached to it. That means you effectively have variable power in the ‘braking system’ and can experiment until you get the best result.

Building some confidence in this sort of device through trial and error plays a vital role in preparing to manage real heavy weather. Feeling that you’re on top of this kind of situation also gives you peace of mind.

Staying safe upwind

Staying safe when going upwind is a lot less complicated. To start with if you’re on a standard charter-style catamaran you’d have to be trying pretty hard to get into any serious danger of capsizing.

Deck hardware may be undersized for the obvious reason that it’s a way to limit cost, but it’s also true that anything that makes it hard to power up one of these boats is going to help keep it right-side-up. In any event it soon becomes obvious (through trial and error) that hanging onto too much sail in a rising wind never pays, so reef early and don’t hesitate to press the engine into service.

As the wind rises, don't put off reefing, shorted sail on the headsail first for control

As the wind rises, don’t put off reefing, shorted sail on the headsail first for control


Reefing is relatively easy upwind, but it’s important to keep the boat moving forward – maybe by keeping the headsail powered up – so you maintain steerage way. If you stop you might get knocked back by a big breaker and that could dig the sterns, which in extreme cases could even result in a stern-first capsize.

More usually, though, avoiding being pushed backwards is more about avoiding rudder damage, which can obviously leave you with a big problem. Starting the leeward engine before reefing (or even tacking) is a good idea just to make sure you can always keep some forward way on and therefore maintain steerage. While strong winds might mean you want to reduce speed, stopping altogether can be just as precarious.

Do’s and don’ts

  • DO keep the mainsail area to a minimum when sailing downwind in unpredictable weather.
  • DO have a go at reefing downwind, even if conditions don’t call for it. At least you’ll find out how feasible it is, which could be really useful on the day when you’ve been backed into a corner and have to try it for real.
  • DO reef early upwind. You’ll probably make better VMG and certainly reduce anxiety on board as the wind rises.
  • DON’T trust a stumpy catamaran with high-volume bows. Far from piercing waves downwind it might just trip up if pushed too hard, so don’t push your luck – especially in heavy seas.
  • If you’re in a bread-and-butter ‘floating castle’ sort of catamaran DON’T expect miracles upwind. The seamanlike solution often involves applying a bit of engine power.
  • DON’T forget that as skipper you’re there to look after the crew, so try not to let fantasies about competing in the Route du Rhum take over. The boat is what it is.


Our eight-part Catamaran Sailing Skills series by Nigel Irens, in association with Pantaenius, is essential reading for anyone considering a catamaran after being more familiar with handling a monohull.

Part 7: Capsize it’s unlikely, but what to do if the worst should happen

AY7Q3617Series author: Nigel Irens

One name stands out when you think of multihull design: the British designer Nigel Irens.

His career began when he studied Boatyard Management at what is now Solent University before opening a sailing school in Bristol and later moving to a multihull yard. He and a friend, Mark Pridie, won their class in the 1978 Round Britain race in a salvaged Dick Newick-designed 31-footer. Later, in 1985, he won the Round Britain Race with Tony Bullimore with whom he was jointly awarded Yachtsman of the Year.

His first major design success came in 1984 when his 80ft LOA catamaran Formule Tag set a new 24-hour run, clocking 518 miles. During the 1990s it was his designs that were dominant on the racecourse: Mike Birch’s Fujicolour, Philippe Poupon’s Fleury Michon VIII, Tony Bullimore’s Apricot. Most famous of all was Ellen MacArthur’s 75ft trimaran B&Q, which beat the solo round the world record in 2005.

His designs have included cruising and racing boats, powerboats and monohulls, but it is multis he is best known for.

See the full series here

A special thanks to The Moorings, which supplied a 4800 cat out of their base in Tortola, BVI.