trailer bunks, tight or not

ssobol

Chief Petty Officer
Joined
Sep 3, 2010
Messages
503
I have a question about the bunks on my trailer. Should they be tight (don't move) or loose (so the bunks can tilt)?

Right now the bunks on my trailer are loose. This means that they can tilt side to side. It takes a reasonable amount of force to move them, but they can be moved by hand. It came this way.

The problem with this is that if there is a cross current or crosswind at the ramp and the boat does not go up the center of the trailer or swings while loading, there is a fairly good chance that one of the bunks will turn and the boat will be resting on the side of the bunk. Unfortunately I cannot see if the bunk is turned until the trailer is pulled up the ramp.

If the bunk is turned I used to have to back the trailer down, unload the boat, pull the trailer up to straighten the bunk, and then load the boat again. Even then it is still possible to turn one of the bunks again if the boat does not load straight up the centerline. More recently I have taken to using a scissors jack (from the van, between the trailer frame and the boat hull) to jack up whichever side of the boat has a turned bunk and turning it back by hand while the boat is on the trailer (it's a smaller boat).

I can see the logic of having the bunks able to move, so that if the boat does not end up in exactly the same place every time, the bunks can move to support the boat better. But since the boat ends up in pretty much the same place on the trailer every time, is this really necessary?

Thanks.
 

boat1010

Senior Chief Petty Officer
Joined
Mar 10, 2009
Messages
781
Re: trailer bunks, tight or not

My opinion is tight. Put your boat on the trailer and make sure they are in the right position and tighten them down. The boat should adjust to the bunks not the other way around. If when you are trailering the boat and they flip it could cause you some bottom damage.
 

am_dew

Chief Petty Officer
Joined
Apr 3, 2005
Messages
417
Re: trailer bunks, tight or not

I have a similar situation with my bunks, however I have them tightened up to the point where they won't go straight up without some force. They used to be real loose and I occasionally had the problem of them standing up at the ramp when trailering the boat, but since I tightened them up some, that has not happened.
 

Evinbuck

Seaman
Joined
Oct 12, 2010
Messages
70
Re: trailer bunks, tight or not

With carpeted bunks I would say tight. I can't say I've ever seen ones to be purposely loose?? Now with the roller type bunks it's a whole different story as they have pivot points in all directions allowing the rollers to take the shape of the hull no matter at what point the boat is entering or leaving the trailer. I'd recommend tightening the bunks where the boat is setting level on the trailer and where the bunks are giving maximum support to the hull and transom.
 

cribber

Lieutenant
Joined
May 29, 2008
Messages
1,338
Re: trailer bunks, tight or not

Loose is okay if you are adjusting them for a new boat. Once you've got your setup correct... then tighten the bunks so you have consistency when launching and retrieving.
 

Grandad

Lieutenant Commander
Joined
Jun 7, 2011
Messages
1,504
Re: trailer bunks, tight or not

Would it be possible to put mechanical stops, such as a bolt installed near the swivel point that would allow the bunk to easily adjust to the shape/angle of the hull but yet prevent the bunks from tipping so far that the boat loads on the edges? I think you'd have the best of both scenarios.
I'd make the tilt range very short, yet sufficient to accommodate slight angle changes as the hull slides into place. - Grandad
 

am_dew

Chief Petty Officer
Joined
Apr 3, 2005
Messages
417
Re: trailer bunks, tight or not

Would it be possible to put mechanical stops, such as a bolt installed near the swivel point that would allow the bunk to easily adjust to the shape/angle of the hull but yet prevent the bunks from tipping so far that the boat loads on the edges? I think you'd have the best of both scenarios.
I'd make the tilt range very short, yet sufficient to accommodate slight angle changes as the hull slides into place. - Grandad

This is the way my bunks operate...although not intentionally. I started out with bunks that were fixed but over time, they have loosened up a bit and they now have some play in them, but not enough to make them stand straight up. I think it's related to how tight the swivel bracket is fastened to the bolster bracket -- too loose and the bunks will stand up -- too tight and the bunks are fixed. I check them each time I re-trailer to see how much play they have and I've only had to tighten them a few times in the past 7-8 years.
 

Jetwash

Seaman Apprentice
Joined
Jul 12, 2011
Messages
49
Re: trailer bunks, tight or not

Bunks are installed for boats that dont need rollers. The hull is simple and are usually accompanied by a set of rollers in the center. Its where it rides on the highway that matters most. A lot of big boats are stored on 3 stacks of lumber. Its not moving. I doubt your boat needs to follow the contour of a movable bunk while its being loaded.
 
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