1979 Fastnet disaster
The decade ended with one of the biggest disasters ever to hit the boating world. Three days into the 600-mile race winds built unexpectedly to a sustained Force 10, with some competitors recording gusts above 70 knots.
In all 24 yachts were abandoned, five of which sank, 15 competitors lost their lives, and a further six people on non-racing yachts in the area also died. That toll was despite the largest ever peacetime rescue mission, involving some 4,000 people. More than a third of the fleet experienced a knock-down to 90° and a quarter beyond that, including many boats that fully inverted or pitch poled.
Part of the problem was that the IOR rule penalised righting moment and encouraged low ballast ratios. This effectively banned low centre of gravity keels, which made knock downs and inversions more likely. The problem was further exacerbated by the trend towards wide hulls that are more stable in the inverted position.
Since many new cruising designs of the day were based on a successful IOR hull, there’s also a raft of cruising designs that have less than ideal ultimate stability. For cruising sailors the legacy of IOR means many thousands of affordable boats built during one of the most active ever periods of boatbuilding lack the stability they could have.
The effects of this are two-fold. In moderate conditions reduced stability means a more tender boat that needs reefing earlier and more frequently, and one that will respond to gusts in a more dramatic manner. In extremis, if caught in severe weather lack of stability makes it easier for wave action to capsize a boat. And if it rolls to 180°, a design with a low AVS will have less chance of being righted in a timely manner. On a positive note, the subsequent inquiry led to important improvements in lifejacket, safety harness and liferaft design.
One other important point is rarely made in this context. The accuracy of medium term weather forecasts has been improving at a rate of around one day per decade since the late 1970s. In other words the six-day forecast now has similar accuracy to the 48 hour forecast in 1979.