I can think of two reason not to fill your aluminum mast with foam.

1. Strange things can happen to uncoated aluminum it is prevented from
oxidizing naturally. (never been a need to paint the inside of a mast in all
these years)

2. In open water, rough seas, I don't think I would want a floating mast
along side. I would prefer that it fill with water and hang below the boat
until the rigging wires can be cut away. It is bad enough when the sails
trap air and keep the mast and boom at or near the surface. Like a battering
ram. I have experienced two de-masting in 45 years of sailing and the most
damage I have noted (aside from the mast) has been to the hull at the water
line due to the floating mast. (once with a solid wooden mast and once with
an aluminum).


--
My experience and opinion, FWIW
--
Steve
s/v Good Intentions


"Robert or Karen Swarts" wrote in message
...
Primary reason is that it increases righting moment in the event of a
capsize. I suppose it might also keep the mast from sinking in case of a
demasting.

Might make the mast marginally stronger if completely filled.

I also misspoke in this area in that what I was envisioning was plugging
the mast with foam rather than completely filling it.

BS

"Bowgus" wrote in message
...
I give up ... why would anyone fill a mast with "foam"?

"Robert or Karen Swarts" wrote in message
...
Assuming one makes provision to access and mechanical or electrical
components within the mast, are there any compelling reasons NOT to foam
fill the mast?

Bob Swarts