to high

stingray · 24 January 2009, 20:21

why are all trailers made with rib/rollers set to high, surely the lower the the rib sits on trailer the better,for towing and launching,every trailer i have ever had i spent days getting it lowered.

JSP · 24 January 2009, 20:46

If it's a roller coaster type you mean then I expect it's to make sure there's enough clearance. If it's got keel rollers then your at the mercy of the axle.

How do you lower yours?
Makes sense like you say to have weight as low down as possible.

Richard Selman · 25 January 2009, 07:36

You have to allow for the point of the bow rising/falling between the rear rollers. If the rollers are too low relative to the roller beam or axle the bow may strike. My boat looked way too high on the trailer until I got the dry suit on got under the trailer and measured the clearance just as the boat cleared the last roller. I fitted a keel roller to allow me to drop the rollers a couple of inches. If you float on then this is less of a problem but you probably can't guarantee this will always be the case. I normally launch on gently sloping sand with a bit of sea motion. To keep the vehicle out of the water its a long hard winch.
Richard

Chris · 25 January 2009, 19:18

I spent a couple of hourse getting my Dixon Bate set up right and it was well worth thr trouble. I needed to move the Axle forward about 2 feet and then was able to lower all the rollers down a few inches until I could just get the keel on without striking the axle.

Its now a really great trailer to launch and recover from.

jyasaki · 26 January 2009, 17:32

For most inflatables, it's the tubes and the height of the fenders that determies the boat height when on the trailer.

RIBs (and SIBs, for that matter) tend to have a flatter and wider overall bottom than hard boats; the tubes extend to or beyond the fenders, whereas a hardboat will nestle down between them.

At least, that's what I've seen...

jky

Richard Selman · 27 January 2009, 08:14

Quote:

Originally Posted by Chris

I spent a couple of hourse getting my Dixon Bate set up right and it was well worth thr trouble. I needed to move the Axle forward about 2 feet and then was able to lower all the rollers down a few inches until I could just get the keel on without striking the axle.

Its now a really great trailer to launch and recover from.

2 feet! What did this do to the hitch weight?

9D280 · 27 January 2009, 09:58

Quote:

Originally Posted by Richard Selman

You have to allow for the point of the bow rising/falling between the rear rollers. If the rollers are too low relative to the roller beam or axle the bow may strike.

I got round that by moving the swing beam rollers out from the keel as far as they would let me, but spread them slowly (a few recoveries were made that day!) until I had them as far apart as the bow shape would let me. They ended up remarkably close together, but I then set the forward rollers (beam for them is about 6" ahead of the axle) on longer poles further apart - they are wide, but high enough to "catch" the bow before the hull hits the axle, and are positioned almost under the toobs, as far apart as I could get them to stop it swaying. Theory is the rear rollers hold the engine up, the "mid" rollers stop the boat swaying from side to side. There's another keel roller on the drawbar which between it & the bow snubber hold the front end up.

The good thing about trailer & boat geometries is that the cross beams (swung or fixed) of a trailer are far flatter than the V of your hull - just moving the rollers outboard by an inch can result in a spectacular drop in the height of the boat without allowing it to hit any metalwork. - Keep the rollers as close to the bar as the clamops will allow, and adjust sideways until you get a "meet".

I will in the fullness of time add another set of rollers to the swing beam to give the transom maximum support (they are not needed for launch or recovery), but as Chris says, a couple of hours setting up is well worth the effort.

Chris · 27 January 2009, 11:20

Quote:

Originally Posted by Richard Selman

2 feet! What did this do to the hitch weight?

Richard The trailer was set up incorrectly from the start so by moving the axle forward I was able to get the noseweight spot on. Initially I could not even lift the hitch.

Richard Selman · 27 January 2009, 12:12

Quote:

Originally Posted by 9D280

I got round that by moving the swing beam rollers out from the keel as far as they would let me, but spread them slowly (a few recoveries were made that day!) until I had them as far apart as the bow shape would let me. They ended up remarkably close together, but I then set the forward rollers (beam for them is about 6" ahead of the axle) on longer poles further apart - they are wide, but high enough to "catch" the bow before the hull hits the axle, and are positioned almost under the toobs, as far apart as I could get them to stop it swaying. Theory is the rear rollers hold the engine up, the "mid" rollers stop the boat swaying from side to side. There's another keel roller on the drawbar which between it & the bow snubber hold the front end up.

The good thing about trailer & boat geometries is that the cross beams (swung or fixed) of a trailer are far flatter than the V of your hull - just moving the rollers outboard by an inch can result in a spectacular drop in the height of the boat without allowing it to hit any metalwork. - Keep the rollers as close to the bar as the clamops will allow, and adjust sideways until you get a "meet".

I will in the fullness of time add another set of rollers to the swing beam to give the transom maximum support (they are not needed for launch or recovery), but as Chris says, a couple of hours setting up is well worth the effort.

I spent afternoon setting up the trailer and I put the rollers out to the side for that very reason. Winched the boat back on again and went home happy. The following day was a very high tide and the trailer was sitting flatter. Tried and tried again but no matter what I did, the rollers kept jamming on the chines (hot day (for Peterhead) drysuit on, getting angry). Had to reanchor off, spend an hour realigning the rollers and do it all again.

9D280 · 28 January 2009, 08:55

Quote:

Originally Posted by Richard Selman

I spent afternoon setting up the trailer and I put the rollers out to the side for that very reason. Winched the boat back on again and went home happy. The following day was a very high tide and the trailer was sitting flatter. Tried and tried again but no matter what I did, the rollers kept jamming on the chines (hot day (for Peterhead) drysuit on, getting angry). Had to reanchor off, spend an hour realigning the rollers and do it all again.

Yep, been there, done that etc etc.....

The only consolation is that you only need to do it once!