Thanks J, a great read about an impressive guy.

Speculation about things like this is a flame magnet but I think it serves a
valuable purpose in helping anticipate and mitigate threats. Being right
about the specific incident isn't the point, thinking about possibilities
that could effect you is.

Having spent some significant portions of my professional life calculating
and thinking about how vessels break, flood, and sink, I find the sinking
by the stern possibility mentioned quite plausible. The problem is that it
requires a hole in the aft part of the boat since vessels usually start to
trim towards the damage. Boats, especially light ones with light ends, will
also usually dissapate a lot of collision energy by the fine forward end
gradually lifting or turning the bow. A sharp heavy object, with it's
effective weight increased by being entrained in the water, could puncture
the forward part of the hull. The nightmare object in my mind is the corner
of a barely floating shipping container lost overboard.

A major hull breech aft is harder to explain but there are two
possibilities, the rudder and prop. An object awash and nearly invisible
might be spotted at the last moment. An instinctive quick turn to avoid it
when the boat was moving fast could swing the stern into it and hook either
the rudder or prop. The geometry of neither is such that much energy would
be dissipated by movement of the hull. Hull failure around the rudder stock
or the shaft pulling out of the coupling (many similar boats have enough
clearance behind the prop to let the shaft come clear of the stuffing box
and shaft tube) could have set off rapid stern flooding and trimming. This
quickly would have cascaded into back flooding through the cockpit scuppers
and then through the companionway which certainly would have been opened to
see why the boat suddenly seemed stern heavy. It would have been very easy
to have focused on plugging a leak and not realized that the companionway
had reached the waterline. The water level would have still have been
fairly low inside the boat at this point and a wave, the stern heavy boat
now having swung downwind, could have sent a large slug of water down the
companionway completing the sinking in seconds.

There is a theory and possibility that Titanic could have survived the
iceberg impact if they had not attempted to turn, thus turning the collision
into the long sideswipe that opened up so many compartments. The same thing
can happen to modern sailboats with their delicate hull appendages. A
sailboat trimming by the stern as it floods will go down a lot faster than
one trimming by the bow.

I wouldn't want this taken as a recommendation to steer straight into any
floating object you see at the last second but, as anyone who has dodged
lobster pots in a separate rudder boat knows, the reverse turn back
"towards" the object is essential to avoidance. Often, when I spot a pot
pulled nearly under by the tide, I find myself close enough that it is
better to just hold the course and hope than to risk swinging the stern into
it by turning. I imagine it would be damn hard to remember that though if
something like a shipping container or giant log suddenly showed up less
than a boat length ahead.

--
Roger Long