Adjust rollers with boat on trailer?

[Fisherman Rob]

Is there any way to adjust your rollers while the boat is on the trailer? Can you adjust one set at a time while supporting the hull with a jack? What would work best to spread the load on the hull?

 

[high tide]

Just did my bunks last spring. It is very important to displace the load over a large area. I built 2 foot x2 foot huge cribbing blocks, about 2 feet high eventually under the stern and hull , also 2x6 and 2 x8 to spread the load. Be very careful and crib as you go with your jack. Not a fun job but easy to do if you take your time and be safe. Be sure to anchor the tongue and block wheels too front and back before starting on a dead level . Good luck
HT

 

[scott craven]

I've replaced rollers using that method.
Might be difficult to get both sides done unless you use 2 jacks.
be careful to distribute the weight across a reinforced section of the hull
so you don't punch a hole in it.