I bought a 1648 jon, motor and trailer some time ago and have been working on it for a while. The trailer is an odd one.
This the trailer tongue in the Normal mode:
Pull this pin:
and you can do this: Great for launching in ponds where there is not a launch ramp. The rear tires of the truck stay up on solid ground.
The original owner mounted a cross member to the bunk brackets and then mounted the bunks to the top of it. Made the bunks very high above the trailer frame: You can see the rear cross member is split.
I removed all of that:
Here is one of the bunk brackets installed on the trailer frame. I used the hole directly under the L bracket for the top of the U-bolt to get the bracket (and the bunk) as low as possible.
It sits like that for now, waiting for the wood preservative I applied to the two 10' bunks to dry. I will install them, and top them with slicks made from vinyl fence posts from Lowe's.
Here are the new bunks:
and here they are covered:
They work very well. I power loaded the boat using the trolling motor. Can't get much better than that.
I have to make new guide bunks as the old ones now hit the gunnels rather than the side of the boat since I lowered the boat on the trailer. I have some fire hose I will split to cover those to keep from scratching the sides of the boat. Then install the new winch tower I got from another trailer. I will use it the rest of the summer and fall and come winter I will redo the axle with new hardware and begin the painting process. Stay tuned.