| Thinking about sinking. The harry ww hulls have watertight bulkheads just aft of the solid foam bows, at the beams and midway. Roughly speaking, the hulls are divided into 4 watertight compartments. Thus, if one is holed, the hull will lose 25% of it's buoyancy.

Looking at the ex40, I don't see any water tight bulkheads? The C50/C60 does though.

But, while on the topic of sinking
https://www.youtube.com/watch?v=H5PDuXvqL7c
This is the yatching monthly crash test boat through hull failure video. They simulate a seacock fail under a sink.

Should a hp design have little or no 'stuff'/composite furniture/whatever (please help me with the awkward language) below the water line? So as to avoid the problem of ripping out a sink, like the video, to get access to the hole in the hull? Some of the cool vids show baths that have some cabinets, but those are no where near as complicated as the one in the vid. Although the may be after being fully plumbed.

On the topic of flat hulls, especially the II hulls, it seems easy to have a short length of hull molded sheets of just fiberglass (thin, light, flexible) including, perhaps the rounded corner/chine ready to go if there is a hole event. Easy to store flat against a hull or in a toy box, and if layed up on one part of the hull, or in the actual mold, they work almost anywhere on the boat to plug holes, from either side.

| If it drew 300mm/12" before the hole, it would draw 400mm/16" with one compartment flooded.  ie the depth of water in the flooded compartment would be 400mm/16".   Too much for a hole saw or electric tool, but possible with hand tools.   Actually less due to the foam in the hulls and the hull flare, but this is near enough.

Again, I don't know what design has said bulkheads, but, if one expects the water rise to be some amount (say 16"), and the design has a clever, high enough wall, as part of some other furniture or something, that otherwise useful part behaves just like a water tight bulkhead, without having to seal all the way up.

| As to whether it would be better to be holed offshore or near shore, I would choose offshore. Near shore, if the problem is rocks or reef, the damage will likely get worse, and eventually you may have to abandon ship, which will probably be hazardous. Offshore, it is unlikely to get worse and you have plenty of time to think about a solution and implement it.

Great point! The near shore taking on water also raises the chance of another hole as you take on water.