Life at the Extreme - Ep. 27 - 'Cold sweat' | Volvo Ocean Race 2014-15 

Joseph Felber Hi Joseph. I think that because the keel is canted to windward it will impede the righting of the boat when it goes over (remember it is lying over on its windward side). It would probably need to be reset to centre or over to the opposite side so that it could help with righting the boat.

John Ivory I wonder if a canted keel increases the risk of a Chinese gybe as opposed to just broaching to windward. Anybody?

Joseph Felber Hi Joseph, The boat is initially heeling to leeward but if conditions are rough and/or if it is sailing very deep downwind it may start to roll excessively to the point that your rudder/s lose purchase and you lose control. Sometimes it will just roll too far to leeward and spin out, rounding up to windward (a windward broach). Other times however it can roll too far to windward under the momentum of the rolling action. The boom will then be stuck up in the air and will gybe across the boat because of gravity and the top of portion of the sail filling in the wrong direction.

Joseph Felber Technically, a Chinese gybe is a gybe when bottom part of the sail is on one tack, while the other is on another. It probably gets its name from junk rigged Chinese boats, which were prone to that because of battens. Nowadays high performance sails behave similarly to junk rigs. Yes, I think that canting keel contributes to the problem here. If a boat heels over to windward due to waves or a wind shift, the keel provides no righting moment, because it points directly downward under those conditions. So the way I see it (not necessary true, mind you), is that first we have a sudden gust of wind, which usually means that the wind changes direction too. Because of that the boat goes pretty much directly downwind, or maybe even on a slightly wrong tack, and at this moment there is also a wave which leans the boat to windward. The wind upstairs is fuller than on deck, so it pushes the top of the main on the other side, which heels the boat even further and causes it to broach. Maybe the top is "flopped" over with the motion of the mast? The keel is canted the wrong way, all the weight is stacked on the wrong side, the boat goes over. I might be wrong though, and it could be that it starts down low by the boom, but however it really happens, we should expect to have the main partially on one tack and partially on another.