180 Sportsman Trailer bunk/roller setup pics

The (2) 2x4's are plenty to support an 18' boat, so no problem there. Getting more hull contact would be good, so as not to rely so much on that bow keel roller. From the pictures, it looks like you could drop the rear support lower and/or raise the front support. If you can move the front supports a little closer together (might be tough with that type of rear support), that will help, as well (essentially the bunks would be closer together at the front than the rear).

Why the wood under the frame? Is there not enough tongue weight? You'll want to address that, too. You shouldn't need wood support to keep the rig from tipping up when entering the boat from the rear. May need to move the axle for that - depending on how much you can move the winch stand... and then ideally move the 2x4's forward as well so you don't have so much 2x4 sticking past the rear of the hull.

For the most part, a hull is a hull is a hull and it's really no different than all of the ones I've set up in the past. Lowering the rear or raising the front supports would definitely help - but if you need the clearance, then that's different. One more thing I just noticed - that rear support has a second bolt in it - preventing it from swiveling (assuming it's similar to the ones I am used to). Take that out and raise the front supports - that should allow the bunks to bend more to better contour to the hull. In the front, if there isn't enough adjustability left, add a 2"x4"x18" spacer.

Are you measuring the tongue weight directly under the ball coupler? Assuming yes... you can use math and physics to your advantage to still use that bathroom scale. There's plenty of google info out there on this so rather than wear out my fingertips, here 'ya go: https://www.etrailer.com/faq-how-to-determine-trailer-tongue-weight.aspx

290 is plenty - you can go less, too. 5% to 7% is standard issue for boat trailers. Doesn't hurt to be a little heavier, though - with a little boat, it's not that big of deal.

FYI... there's no real need to take the weight off the suspension/tires. Certainly do it if you want to, but there's no effective/real world benefit. I have NEVER seen an early failure (I see hundreds of trailers every year) due to compression... and there's the masses of suspensions everywhere... boat trailers, landscape trailers... heck trucks and cars... that sit on their suspension year round. This is more one of those "makes me feel good" things - which is fine. But I'm mentioning this simply so you're aware and if you wanted to not worry about it anymore.

Recoil Rob said:

BTW, are 2x4 bunks supposed to bend to contour to the hull curvature?

Click to expand...

Yes, whether 2x or 6x on the flats, they follow the hull. Because that rear support is not pivoting, it's basically creating a 3' length where no bending/curvature is allowed - which then creates less length to where the wood can naturally bend.

I'm looking at your first picture again... it sure looks like the front support is actually lower than the rear. If what I see is right, that's making the issue even worse because it's pulling the front half of the 2x down and away from the hull.