I'm in over my head here but I believe the major difference is fiberglass rods tend to occillate more than graphite in the cast recovery (low modulus).
Fiberglass rods heavy enough to fish in the salt are just that,heavy. My Orvis Golden Eagle 8wt custom is a whopping 7.5 ounces. It casts like a cannon but it's too heavy to use all day. It's excellent for casting big hair bugs.
There are plenty of good old rods out there if you want one. Phillipson, Winston,and the SA System 9 rods are some of the best in the saltwater sizes.
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"The trout were laughing so hard at us that they considered evolving legs so they could crawl on to land and catch their breath"
Dave Barry
[This message has been edited by dudley (edited 12 October 2005).]
The simpler the outfit, the more skill it takes to manage it, and the more pleasure one gets in his achievements.
--- Horace Kephart