I added an axle to the trailer on our 22' Angler. The trailer was a Pacific, single axle with drum brakes. I bought parts (axle, springs, fenders, ect.) from Champion Trailers (www.championtrailers.com) I moved the old axle forward, shortened the brake lines, and put the new (nonbrake) axle behind. Did the modifications on the driveway, by jacking the trailer up and putting it on blocks (boat and all). Worked well, I pulled that boat for thousands of miles on the two axle set up.
You may want to check your state regulations before purchasing your new axle. a lot of states require that both axles have brakes on them. I know here in WA we need both on any weight over 3000 lbs.
