Re: behind mast furler
That Selden system manages to deal somewhat with the major (performance) problem of behind-mast furlers by closing the gap between the sail and the mast. It is more weight aloft, but it also allows a standard mast section to be retrofitted.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)