I've had excellent success using fly rods off downriggers, or even mooching, with the following mooching reels that will fit the smaller reel seat usually found on a fly rod:
Daiwa 175 - the old classic! One way drag, a ratchet that'll make your hair stand on end, and pretty light weight. Not in production any more to the best of my knowledge. Try garage sales or ebay.
Shimano GT 1000 - The "newer" choice. Smaller diameter , but wider arbor than the GT 2000. Same Shimano drag system that you can beef up yourself if you like, light weight, decent ratchet. I'm not sure if they still make these or not.
Islander MR2 - The expensive choice. A great reel, but for five hundred bucks it should be. I use them on my boat almost exclusively, but then again I tend to fish a lot. Kinda heavy would be my only complaint. I hear there are some knock-offs available nowadays for a lot less money. Don't know about the size of the reel seats on them though, and therefore their adaptability to a fly rod.
For using fly rod off a downrigger keep these tips in mind:
- don't go lighter than a 9 foot 8 weight (and thats pushing it!)
- use 25lb or less mainline.(I use 20 lb Big Game.)
- NEVER overload the rod by holding it way over your head. You'll be tempted to do so in the final stages of landing a fish. 90 % of the time, you'll be rewarded by a loud crack and a broken rod if you succumb to the temptation.
- don't use flashers, and only put the line a maximum of about 3\4 of the way in to the clip.
- don't use the rod to pop the line off the clip to check bait etc. Rather, either let the downrigger bring it up, or grab the line with your hand and pop it that way.
- If you're going to mooch, and use a sliding weight, ALWAYS place about a 1.5 inch piece of surgical tubing above the weight sliding on the line. If not using a sliding weight, use a big idiot bead or shorter piece of tubing.
- softer, slower action rods (usually cheaper) tend to be more durable and work better than your high modulus graphite, high end rods. I've used a 9 foot, 9 weight Berkley Pro-Angler (bought for under $70.00 from Wal Mart)for about 3 years now and it seems to have lasted..
I hope this helps.
Have fun...
Gooey.