Winter storage on the trailer

[JimInPB]

... The previous owner told me that I shouldn't store it long-term on the trailer without putting the boat on blocks because it was bad for the trailer suspension or something like that. Any truth to this?
...

There are two issues that I am aware of. The tire issue has already been covered. The other issue is cracking the fiberglass. On cheap boats, like Bayliners, I have seen patches of glass blown out of the bottom of the hull in the exact spot where the hull rested on the trailer rollers over the winter. This resulted in the boat sinking very quickly.

When you have thin glass that is supported in a very small area, this can be an issue. When the quality/thickness of the glass work is better &/or the supported area of the hull is larger, there should be no problem. All the boats that I currently own live on trailers & are supported on bunks year round. I have had no problems.

Edit:
Actually, add to that a third possible issue. If you have torsion axles on the trailer, it might be a good idea to block up the frame of the trailer & take the load off of the rubber bushings for the winter. This is probably not all that critical. Most boat trailer axles die of rust before the torsion bushings blow out.

 

[Leeward Rail]

Tires are the big issue.
Sun damage... Damage if they slowly go flat over the winter. Increased incidence of sidewall cracking where the bottom bulge is etc.
Of course you can simply buy new tires, but it's nice to extend the life of your tires.

I have welded two adjustable fold down legs behind the axle.
When I crank the tongue up it puts more load on the legs.
It stabilizes the trailer when I am raising the mast or working on the boat in my yard in the spring/fall, in addition to taking some load off the tires.

For the winter, at it's farm storage locations, I add some blocks.

FWIW, almost every boat trailer (road and yard only) at our marina sits on blocks during the winter.