Nutsy,

Have you ever seen a Doyle Stack Pak on a racing boat in a race? I don't
think so.

The biggest objection I have to them, is the ungodly amount of windage
they create on a Main that you are paying good Dollars to make
efficient. Easy Yes; better than nothing????

Your boat really would suffer badly with a Sack Pak. Your larger Main is
your primary driving engine and a Stack Pak flapping around the Boom
with connected Lazy Jack would be a bad thing

Ole Thom;--- Beach bum