Can a Yacht capsize? ‘AVS’ or Angle of Vanishing Stability

Stability video cover

Can a Yacht capsize? ‘AVS’ or Angle of Vanishing Stability

Can a Yacht capsize and how stable is a Sailing Yacht? Many of us ask ourselves this question every time we go sailing on a windy day when the boat starts to heel over. Is normal for a sailing yacht to heel over some degrees when sailing. Depending on the boat design, amount of sail area and wind force, sometimes we can safely heel over 20 degrees or more… it is all part of the fun of sailing (Catamarans are an exception to this, since they heel much less than monohulls).

The truth is that they are VERY stable. In fact, for a yacht to capsize there would have to be a very bad structural failure (like the keel falling off) or a huge wave (I mean HUGE, like the ones in the movies) to hit our boat.

We measure stability on yachts in categories, A,B, C, D. That determines what conditions the boat is designed for, whether it is designed for Ocean sailing, Coastal or just to potter around the shore. For each category, there is a measure in degrees, as for how much the boat will have to roll or heel for it to stay inverted, instead of turning back to its upright position. This angle is called AVS, or Angle of Vanishing Stability.

For instance, our yacht NISI, an Elan Impression 394, is in yacht category A, with an AVS of almost 130 degrees. That means that our design is capable of ocean sailing and is very, very stable.

There are many factors that can compromise the stability and buoyancy of a yacht, besides the weather (back to the Huge wave), like the distribution of the weight an the boat, flooding, too much sail…. factors that a good skipper always have in consideration when going out at sea. To have a better idea of all this, we have made a little video that explains the forces  involved in giving stability to our yachts, and how it is measured.

 

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