Testing Boat Stability and Capsize Righting
It is a great pity that David Weinstock resigned when his kind offer to arrange capsize testing was not taken up, but I understand that his club officials could not accept old, unusual or modified boats for testing, and most DCA boats are old, unusual or modified! Perhaps David can take heart from the fact that many members are now writing frankly about their capsize experiences, and also from the concern expressed over this matter at this year's AGM, and the further kind offer of capsize testing at a site near Ipswich. I feel that capsize testing will eventually become quite common, if not the norm, in the DCA.
Testing recovery from the normal 100° capsize is of course easy since it can be carried out in water only a little more than centreboard depth. Testing recovery from a turn-turtle capsize is obviously much more difficult because it has to carried out in water deep enough to give clearance for the mast/gaff, and because even with rescue boat assistance, righting certain boats from inversion may be very difficult, and I am advised that the supervision of a qualified instructor is an official safety requirement. Modified boats are suspect because even extra buoyancy bags in the wrong place can not only make recovery more difficult but may make the boat more inversion prone! Personal testing is important because height, reach, weight and strength all affect one's ability to right the boat. Short light people can right 16 foot Wayfarers, but it takes know-how and practice.
DCA Boat Descriptions are now revealing the shortcomings as well as the advantages of member's boats, but we still need to be explicit on whether and how well our boats meet our recommendations for stability and capsize recovery. Take my boat, a Mk 114 foot Leader as an example. A DCA stability test carried out at a rally using a number of volunteers of varying weights, revealed that it took a 12 stone plus an 11 stone person sitting on the gunwale to bring it to the point of dipping under. (The crew must be sitting fully on the gunwale, not just on the side-deck!) The DCA recommended minimum weight is one stone per foot of waterline length, so taking the overall length of 14 feet as a safe approximation, it was found that the Leader exceeds the DCA recommendation by 23 – 14 = 9 or a factor of 1.65. This may sound impressive but I would expect some cruising dinghies may have a stability factor as high as 2 or 3 or more.
However it is now generally accepted that very stable dinghies tend to be very stable the wrong way up, so we now have to consider stability in relation to DCA capsize recovery requirements: - The Leader's capsize recovery characteristics are about as good as they get. I have tested mine for normal 100' capsize in moderate conditions and found that by standing on the centreboard close to the boat it comes up in about four seconds, just time to get in the boat as it rights itself. There was of course water over the floorboards, but the Leader will sail flooded. I have not had the opportunity of personally testing the Leader for inversion-recovery, but its recovery characteristics are very similar to those of its larger and more stable relative, the Wayfarer. Readers may have seen the TV programme in which a diminutive female, using the RYA method, righted a Wayfarer from a turn-turtle capsize in seconds, scooping up her crew (the late Jill Dando) in the process. The 14 foot Leader is righted in the same way.
This makes capsize recovery sound easy. At sea of course it can be very, very different. In heavy seas even heavyweight instructors may fail to right a Wayfarer, let alone more difficult boats. Cold and shock numb the brain, strength soon ebbs. Capsize offshore, and one is faced with a desperate bid for survival.
Anyway, we are all agreed that prevention is far better than recovery from capsize, and that inversion must be guarded against as top priority. Forward main-sheeting helps avoid mainsheet snagging. On my Leader I never cleat except in very light airs but take the strain manually. (It keeps me warm in winter). Sail-head buoyancy and buoyant foam-filled mast and spars may not in themselves prevent inversion, but will slow it by precious seconds, giving time to get on the centreboard and start bringing the boat up again.