If you add foam insulation, you will be adding weight to the wire bundle
which in your case, is unsupported except where the individual wires exit
the mast. The weight and constant motion will eventually cause the wire
stands to fatigue and break.

I like Glenns second recommentition but while you have the wire bundle out
of the mast. I recommend including an 1/8 synthetic cord, half hitched every
couple fee, down to at least the spreader wire exit. Followed by the long
stiff tie wraps.

Also, when you pull the wires out of the mast, pull in a line that will be
use to pull the wire bundle back into the mast. Leave that line in it's
exact orientation with the internal halyards, to make sure that you don't
end up with a halyard crossing over your wires. This could cause some damage
to the wire due to chaff or strain.

Another possible solution to the original problem would be pour-in-place
foam. Use those weather seal spray cans. and squirt it inside through any of
the existing holes. Use enough to fill the mast section in that area. After
the foam expands, Pull on you halyard (with a winch, if necassary) to free
them from the foam. That should leave a passage for them to run in the
future. This method wouldn't require removal of the mast, just a trip up in
a bos'ns chair.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions