I uploaded 3 pics of my trailer showing the front and rear roller bunks and the space between them. I want to remove the roller hardware and mount wooden bunks for the boat to sit on using the roller frames to maintain the proper height so the boat clears the trailer fenders. The question is should I use a long bunk on each side of the trailer spanning the space between the front and rear roller frames or use 2 short bunks on each side of the trailer mounted independently on each roller frame ? This is for a 19 foot starcraft aluminum boat with a 115 merc

Every trailer I've ever owned or seen had long boards.

Your boat sits fairly high up, like you mentioned, in order to clear the fenders. If you use bunks that span both carriages, you'll lose the ability for the rear set to pivot as the V starts entering the gap between the bunks. As long as the ramps you use have a pretty good angle to them, you'll be fine. But, on a shallower ramp, the ability to pivot the rear set may come in handy.
Did I ever send you these pictures?
HRG

Your boat sits fairly high up, like you mentioned, in order to clear the fenders. If you use bunks that span both carriages, you'll lose the ability for the rear set to pivot as the V starts entering the gap between the bunks. As long as the ramps you use have a pretty good angle to them, you'll be fine. But, on a shallower ramp, the ability to pivot the rear set may come in handy.
Did I ever send you these pictures?
HRG

yes you did, your rollers set lower than, mine which are on a kind of U shaped bracket and I have to maintain heigth to avoid hitting the fenders. I like the idea of only changing the rear rollers to bunks for the reason youy said, shallow ramps.

however usually they are usually mounted at each end. Mine would have a long piece at each end and I don't thick they would flex enough to conform to the hull

I switched my trailer from rollers to bunks last year. I went with two sets instead of one longer one and have had no problem at the ramps what so ever. I just removed the rollers and mounted the bunks to the frame the rollers were attached to. This way I still have the flexibility of a roller trailer, (the bunks now pivot) instead of a "hard mount " bunk trailer.

JohnB.O.A.T.

I switched my trailer from rollers to bunks last year. I went with two sets instead of one longer one and have had no problem at the ramps what so ever. I just removed the rollers and mounted the bunks to the frame the rollers were attached to. This way I still have the flexibility of a roller trailer, (the bunks now pivot) instead of a "hard mount " bunk trailer.

JohnB.O.A.T.

John
what make and model is your boat, by chance do you have pics of your trailer

Well I converted the back two roller gangs to bunk and I have to say so far I am very disappointed. I have to back in the water til my rear trruck wheels are in the water to get the boat off the trailer and the same if I crank the boat back on the trailer. If I drive the boat on the trailer it takes alot of power to get it on, and so very hard to crank the last foot or so. I am trying to find a way to gt the bunks to sit lower on the trailer and so far a at a loss as to were to find the right brackets or to make my own brackets. It looks like I may have to go back to the roller setup and just add a few new rollers to add support for the hull. Perhaps this is just inherent with bunk trailers.
Any feed back would be appreciated

Rebs,
Can you add a few pics to your album showing the bunk conversion? I'm also thinking that maybe some silicone spray on the new bunks would help. Worse case scenario, Fulton makes a 30" long swing tongue kit, that, depending on what your coupler area looks like, could add 2-1/2' to your trailer length, to avoid getting the truck tires in the water.
HRG

I add the Fulton Swing away to my trailer ... its awesome! I can launch in shallow ramp areas much easier because of the added length. I purchased the "NEW" model which has better hardware and the additional length which the older one I dont think had. It does double duty... helps save space in the garage AND added those extra feet to my trailer at the ramps.

a lot of the bunk trailers I have seen seem to be set lower to the ground.

I think converting a roller to a bunk might be more trouble than its worth on some applications

my Shorlander roller has been fine, very easy to use. Very happy with it

my new boat has a bunk trailer, its a lot bigger boat but I have to pull a lot farther in the water. But it works great, as its custom made for the boat and i do love