That kind of cracking does not just happen on lightweight boats. That same kind of vertical hull crack, aft of the front beam, happened to us on a Hobie 18. I, as crew, was out on the trapeze, and it was maybe a couple of minutes after the start of the race when all of a sudden the hull just started to split open right in front of my forward foot. Very unusual location for a crack like that.

We managed to get the boat to the beach on the same starboard tack, keeping the starboard hull as far out of the water as possible. (Still got full of water, though.)