It all depends on what you want to do. I hand trolled in the late 70's and grossed about 15-20 thousand a year while guys with small power trollers were grossing well over $100,000. What a mistake that was.
My son recently decided, after he graduated from college, to go into the trolling business. For an initial investment of S2500 he got an old wood boat that was mechanically and electronically sound but a little soft in spots and needed some work. He bought a power troll permit on a handshake and a promise. By taking the risk that he could make big payments each fall he paid off the boat and permit in two years. He sold the boat last spring and bought an aluminum troller worth over $100,000. But, he is an uncommon fisherman with incredible energy, a lifetime of experience, and good partners.
But don't believe those averages for power troll gross. You can not make it grossing that little. You need to gross nearly twice that much to make expenses, pay off your loans, and have something to live on. Those averages are skewed by part time fisherman on the one hand and by freezer troll grosses on the other. Plus, I think 2006 was one of the best troll years in history. The season is from March to November. If you are going to produce in the zone you need to you need to do it full time with passion and dedication. It is a tough business and with declining Chinook quotas and coho abundance likely it is about to get tougher.
If you are going to hand troll I highly recommend you start with four rods and learn how to catch fish. Hand trolling with two wires is an incredibly tough way to go. It is hard on your body and even tougher on your pocketbook if you are a good fisherman. The guys I know fishing that way do so out of a combination of stubbornness and independence that is admirable but still a bit crazy. In steady scratch fishing you can do comparatively well hand trolling but you will be buried during the big days which are really important to putting a season together. I often have three of four days, for example, during the winter that exceed the production from the other 30-40 days I fish. I suspect it is the same for most of the top guys.
The other problem with hand trolling in our quality conscious time is that it is harder to keep up with the cleaning, rinsing, icing, and other immediate chores that producing a high quality troll salmon requires.
Make no mistake, I love handtrollers and admire them. I used to represent them politically and have fought even since I have become a power troller for them to be represented on ATA for example. But it is a tough way to go. I have hand cranked over 100 salmon (coho) from four lines in a day. My shoulders still ache.