Under certain circumstances, I have gone up three line weights without
problem. (I put the wrong reel in my travel bag - duh). The fly line rating
is for the first 30 feet of line. If you are making very short casts,
increasing a line weight or two allows the rod to load more quickly, making
it perform more like the designers intended. Conversely, if you are making
extremely long casts, sometimes going down a line weight or two makes sense.
A recent article in one of the FF mags included interviews with many top rod
company designers. They almost universally agreed that if the rod was well
designed, it would perform well at a wide range of distances without the
need to change line weights. From their perspective, it must be some sort of
insult to even consider using an over or under-weight line, but I can tell
you from experience, it does work. I always overline my wife's rods because
even with a mid action rod, she just doesn't have enough strength to load
the rod. Since doing so, her casting has improved dramatically, her
confidence is sky high, and she is catching a lot more fish because she can
put the fly where it needs to go.

HTH

Jim Ray
"Tony & Barb Vellturo" wrote in message
...
Seems to me I read or heard somewhere that one can go up one line
weight without a problem. That is, with a 5 weight rod one can use a
6 weight line. Can there be a problem with this??

Tony