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MULTIHULL SAFETY

By Ian Farrier

The modern trimaran with its enormous stability and unsinkability is a very safe craft, and has now established an excellent safety record. They have now circled the globe many times at previously unheard of speeds, with week upon week averages of over 20 knots. However, like all modern craft, this safety is dependent on the operator and how the craft is handled and used.

There is simply no safer boat for crews than the unsinkable multihull
with it's spacious and level decks

Their unsinkability is now well established, with the only major hazard being capsize, and a few simple rules make this virtually impossible. Capsize is rare with well sailed cruising multihulls, but can occasionally occur with racers pushed to the limit - just like race cars. I raced and rallied cars for 5 years many years ago, and had one roll over. I have raced trimarans for over twenty five years and have never managed to roll one over.

The important factor, as with a car, is that the degree of risk is up to the driver/skipper. Drive or sail too fast for the conditions and the risk of a crash is higher. The decision is yours. It is not taken away from you by a heavy keel below, making it impossible to go fast. Nobody seriously suggests weighing down a car to prevent a roll over, nor should a sailboat be weighed down to limit performance, just because a few may not have the skill or maturity to sail a fast type of craft safely.

Set up and sailed properly, a Farrier design is a very safe, yet very fast boat. This F-31 is
powering into 25 to 30 knot winds, with a single reef. Speeds of around 11 knots to
windward, or more, are possible in such conditions

Thus, like a car, a multihull has the capability of very high speeds when desired, and the risk factor can consequently be higher. The choice is yours however, as it is not compulsory to go fast. There is virtually no chance that I am going to roll over the family car on the road, and similarly, there is no chance I am going to roll over a trimaran while simply cruising around.

In general, the risk factor will only begin to increase when boat speed exceeds 15 knots while reaching, or about 10 knots to windward. Thus when sailed for the conditions, or with safety in mind, and used as intended, Farrier designs are among the safest craft afloat, and better still, will never leave you fighting the elements alone.

Which would you rather have your family on?

The fully flooded F-27 above left (done deliberately to test unsinkability) or the mono above that is about to sink?

Even this is better - photo by www.pix-u.com

However, the relative publicity given to multihull capsizes compared to monohull sinkings is way out of proportion, due to the unsinkable multihull stubbornly staying around to where photos can be taken, while the monohull abandons the crew and quietly sinks from sight.

One classic incident of 'one-sided' publicity was in the Tasman Sea in 1980, where the 40’ racing trimaran CAPTAIN BLIGH lost a float bow, but stayed upright, and the crew was eventually taken off by a liner. This was front page headline news in Australia “Four rescued off trimaran” etc. But in the same area, and in the same storm, the top line racing IOR monohull “Smackwater Jack” returning to New Zealand from the Sydney Hobart Race disappeared taking five lives. The only press coverage it ever received was four lines in the back pages stating it was missing.

This was headlining a city street fender bender, while the freeway horror smash with five dead is relegated to the back pages. Upon having this pointed out, the editor of the Brisbane paper apologized, but it was not really his fault - the news was readily available on the tri, with nothing other than a 'missing notice' on the mono. But the damage was done. Had CAPTAIN BLIGH sunk and lost her crew, multihulls would have been better off, or perceived as more safe, as there would have been little or no story. But because she stayed afloat and very visible, she attracted the publicity and the multihulls reputation suffered - simply by looking after the crew.

Sinking Is Not A Very Good Safety Characteristic

Sinking can be very terminal, and can result from the simplest of things, from hitting debris at sea, or even a simple malfunction in the boat. It is also far more frequent than commonly believed, as most instances just do not get reported.

AN INTERESTING STATISTIC

Meaningful comparative statistics on safety are hard to come by, but with over around 3000 Farrier designs of various types sailing there are now enough to get an idea. The capsize rate appears to be averaging around 0.2% or three or four per year for racers, whereas a rate more like 0.05% applies to cruisers.

Light aircraft make a good comparison, being another modern, fast and very comfortable ‘high tech’ form of travel. Their accidents are also very visible, well documented, and highly publicized, unlike those of the monohull which tend to disappear, without trace, and thus get much less, if any, publicity.

The current serious accident rate (resulting in death or serious injury) amongst U.S. light aircraft is 1.13% per year down from a high of 10.2% in 1948. Thus for Farrier multihulls to have an equivalent safety record as light aircraft, then we should be seeing around 22 capsizes or serious accidents a year, with the boat and crew also probably being lost as a result. It is not even close.

Not all multihulls are the same however as there are some that use huge rigs along with minimal accommodation in order to achieve high performance, and such boats will have a much higher capsize rate. The Farrier design philosophy is to always have roomy accommodation and achieve high performance by good design and efficiency, rather than brute power. All Farrier cruising designs thus have a wind capsize force of over 30 knots for safety. This is the theoretical amount of wind required to capsize the boat with full sail, sheeted in tight, and the boat at 90° to the wind. Some of the extreme boats can have a wind capsize force of less than 20 knots, which is too risky for any cruising boat.

CAPSIZE SAFETY ISSUES

Capsize is not as hazardous as sinking, but must always be considered as a possibility, even if a remote one, and be prepared for. In this regard, there should always be a special safety compartment that is accessible from both above and below for storing safety gear that will be immediately available if capsized. The following items should always be stored in this compartment, with lanyards attached, and in watertight bags:

EPIRB unit
Cutting Tools
Extra wrenches & tools
Bolt Cutters
Spare Beam Bolt Wrench
Ropes
VHF Hand Held Radio
Pliers
Flares

If an offshore design, then an emergency re-entry/escape hatch should also be fitted as standard, which will allow the crew access both in and out to the boat interior for shelter. Interior should also be setup for inverted living as per the downloadable F-41 detail sheet below.

Surge is the major enemy inside a capsized boat, and the first priority after a capsize should be to seal all hatches, vents etc. and try to keep the boat dry as possible. Pop-top on trailerables will remain in place as this will try to float upwards. Main battery switch should be turned off and all loose objects stored in the cabin settees, these now being above water. Surge will otherwise remove everything. Water level while inverted is around the bottom of the beams - float decks are only just immersed. If possible, the battery should be removed or moved higher as it will discharge under water. It should also only be a sealed unit thereby eliminating the danger of acid or gas. Check also that the watertank cannot drain if inverted, and if so, modify so that it cannot.

One now has a large, relatively comfortable life raft, and well stocked with provisions, which is much better than in a small liferaft with minimal provisions. In fact the record for the longest survival time adrift at sea is now held by the crew of a trimaran capsized off New Zealand in 1990. They were in such good condition when rescued that their story was first believed to be a hoax. The same year the offshore racing monohull GREAT EXPECTATIONS disappeared off Australia, taking 6 lives. Had the crew on this boat been on an unsinkable trimaran, then they may have survived.

RIGHTING A CAPSIZED MULTIHULL?

Righting a capsized multihull at sea, unless outside help is available, is probably not a feasible option with current technology. Best to leave the craft as it is, where the crew are safe, and await rescue. Modern satellite position indicating systems now offer very quick and easy location for a floating, but disabled multihull, whereas a sunken monohull has no such option.

When the opportunity arises, and outside assistance is available, the most successful righting system for any multihull, is to tow the capsized boat fore and aft, the tow line going to the aft end, in the form of a bridle. Which end depends on the boat, but the general rule is to choose the end that is floating highest. Thus as the boat begins to move, the lowest end, be it bows or stern, will begin to sink, and even more so as the water inside rushes forward. The boat should then flip back upright, bow over stern or visa versa.

If the above procedure does not work, then try flooding the end that needs to sink, or add some crew weight (ready to abandon ship once the end concerned starts to go under). If this fails, try towing the other direction. Some controlled flooding may also be required. Towing sideways will not work - fore and aft is the easy and only way to do it.

Another righting method, that uses the Farrier Folding System™, has been tested and shown to be workable on a Farrier designed 19' Tramp in choppy conditions, as detailed below. It has now been used successfully to right several boats, but usually also with some outside assistance. It has not been successfully tested at sea, is not straight forward, and thus it is considered better to wait for assistance, as the righting action does tend to flood the inverted boat more. Not a good result if the righting attempt doesn't work.

TRAMP RIGHTING EXPERIMENTS

The below photo sequence shows different stages during righting experiments with my own Tramp, after it had been deliberately capsized. Righting was proved to be possible without outside assistance, but it was difficult and special preparations are needed. Thus it is definitely not a recommended procedure offshore, but it has been used to right boats inshore (usually with some assistance). However, towing fore and aft is probably easier and quicker (as detailed above and in Sailing Manual). Offshore, it is still much safer to have the boat prepared for inverted living, with a built in safety gear emergency compartment, plus an escape/re-entry hatch, and just stay with it.

There are some who would say a capsized multihull is still more comfortable than a monohull the right way up

Folding while inverted proved relatively easy. Once the beam bolts were undone, folding was achieved by simply standing on the wingnets. One had to be quick to get out of the way in fact. A three foot chop was running at the time but this was not a problem. However bigger waves (6' and above) could be a major problem and likely to start taking the boat apart if the beam bolts were undone in such a situation.

Starting the righting process - two proved not enough with the air/buoyancy that remained inside the leeward float. To make it easier a vent hose can be fitted inside the float to allow air to escape. Interestingly, there was strong tendency for the boat to go fore and aft, and additional diagonal cross ropes had to be used to stop crew from sliding off one end or the other.

Three crew was enough and it is almost there

The right way up

It actually unfolded itself at this stage. This Tramp was designer's
own boat and modified to incorporate an experimental cabin. See also:

A Matter Of Safety

F-41 Catamaran Safety Aspects
(downloadable PDF file)

Another Righting Test

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