Boat Ramps?
 

New to this and not sure but I'd like to use the truck to pull my boat also.

2001 Volvo 660 single axle air ride and double bunk high sleeper with 13 ft hauler bed. Concerned with losing traction on wet boat ramps?

A few years ago, when I was considering a heavy hauler instead of a truck conversion, I spoke to a gentleman who specialized in singling out Semis for towing big 5th wheels. When I told him that I wanted the truck to do double duty as a RV hauler and a boat hauler, he said it was not the solution. His reasoning was just as you stated, not enough weight on the rear axle for traction, especially on slick boat ramps.

Time to trade in for a 6x4 or 4x4 is my suggestion.

An unloaded truck can practically get stuck in wet grass, even with a locker.
It's all about traction. No weight + highway tires + ramp slime = ain't goin' nowhere.

Im building a 1993 fld120 im singling truck and adding a 120inch bunk behind the 36inch bunk. I plan to tow my boat