Hi Alex,

Your example of a capsize from a following wave makes sense.  The form
stability of the flared bow is the result of positive hull speed from
moving forward through the water.  A large enough following wave can
produce negative hull speed or surfing, defeating the righting forces of
the flared hull.

The lesson learned is, contrary to running in fair conditions, keep the
center board down and drag warps or a sea anchor to help the rudder dig
in.  Of course, this puts a lot of stress on the board and rudder, so it
would be unwise to sustain for very long.

As for your other issues:

1.  In severe conditions, deploy a jack line from each aft cleat, outside
the shrouds and to the bow cleat.  Tether to these.  The jacklines should
run outside the shrouds because if you go over from the bow, you can work
all the way aft to the ladder without disconnecting from the water side.

2.  Whether on the water or at the dock, secure your poptop closed with a
line running from the horizontal of the poptop support rod to a jam cleat
on the starboard side of the companionway step.

3.  Whether on the water or at the dock, tie an overhand stopper knot in
the furling line aft of the jam cleat.

Rick