I have a SC1V, 8"6 two piece 4 wt.. My line( @#$%& #5) was not shooting well even after I would wipe it with Fast Cast U-40. I took it over to a young ( good eyes) fly fishing pro. He took one look at my line and said it was shot. Got on some fly fishing webs that night and twice I found and read a very interesting pitch for using Double Taper line instead of the Wt Forward. My son has a Cortland 333 DT , 5 wt. line on an old reel. Line was 4 years old. Under a mag. glass I could tell it was in good shape. I wiped it twice with Fast Cast and put it on my 4wt. It cast wonderful. I used it last night for bluegill and bass on a big farm pond. I was fishing from a paddle boat and there was no wind! I went to progressively bigger flies. Bead head buggers # 6 and large deer hair bugs were not a problem to cast. Question? So I know an older 333 DT # 5 will work well on my 4 wt. Can I assume a newer DT # 5 will be approximately the same or do I have to simply try each individual type of line? Also, would a 4 wt. DT probably have had more problems throwing those bigger flies? I plan to buy new line this week end. Thanks for your thoughts and tips.

The weight per the number of feet should be pretty close, particularly on the Cortland lines. They hold very close to the AFTMA specs for line weights.

Double Taper lines certainly work well. Most fly fishers prefer a WF when pushing out to longer distances, but you can certainly reach most reasonable distances with a DT.

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Hi Steven,

I can see no reason why a current made 5 wt should not work as well as the older Cortland 333. Don't forget that flylines are made to specifications as regards to the weight and to my knowledge the specs have not changed for years.

Yes a 4wt will not throw large flies as well as the 5wt as you need the heavier line to turn over larger flies. If you push things too far with a light line you will have problems presenting big flies and your casting is likely to go to pot especially into a head wind.

Just a quick thought you will be better off using a 4wt in windy conditions as it's thinner profile will cut through the air better. Many fly Fishers make the mistake of up lining by one in bad conditions. You can put extra strain on your blank to if overlining into the wind as you strive to push the rod against the wind causing more load to be applied. The old master tLefty Kreh is also of the same view if that helps.
One last thought you may actually have a rod that is more 5wt than 4wt.

Hope this helps.
Regards Mike