Trailer Bunks

[Cartes Custom]

Rebuilding the bunks on my Boat Mate trailer in effort to improve the cradle my XB21 rides on. You have probably observed the heavy endention on the vertical / outer 2x6 bunks where the trailing edge of our boats rest. This spot of smashed carpet has abraded my gel coat and destroyed the bunker. Thinking about most of weight of the entire boat etc carries on that narrow bunk mostly on the rear 12”; I think we need more boat support from the inner 2x6 bunks. As told by representatives of Allison (with all due respect intended) the inner bunks are only guides and there should be a gap between these inner bunks and the hull when the boat is fully on the trailer. I’m going to allow the inner 2x6 bunks to carry a percentage of the load in effort to spread out the weight distribution. As I am going to change my JP soon moving the motor 2” further back will add additional downward force on the bunks; makes sense to add additional support.

Question: Has anyone extended the inner 2x6 size bunks to the last cross member of the trailer?

Extending the inner bunks to the last cross member seems logical. If anyone knows a reason for not doing this e.g. hull design limits etc please let us know.

Your comments, questions and suggestions are appreciated.

[fishnfireman]

Not that I'm an expert..
Living in West Texas where a one way haul of 400 miles is common, the problems you speak of show up much sooner.
Here's what I've done to both of my Allison's.
When replacing the bunk carpet -- Leave it open on the bottom to facilitate drying. Cut the carpet so it does not contact the metal brackets (they wont rust as fast). I take a router to the top side of the board edges so they won't cut the carpet when loading. Also grind a relief spot in the outer bunks where the "indention" you speak of is. My first boat was worn to the glass before I noticed !!
It's a PIA ----But I've spent hours under my boats making sure ALL the boards have even pressure the FULL length.
I can be hard headed about some things and so far I have found no I'll effects to having even weight on the inside boards..

The only possible draw back I might have with extending the inner boards farther back -- would be loading on some ramps.

[JOEALLY]

I've always considered the inside boards to be guide boards only. My boat was sitting with weight on the inside boards and also created the indention in the carpet where the rear of the boat sits on the vertical boards.

When I re-carpeted my bunk boards I adjusted the vertical boards a little higher so the inside boards have about 1/8" clearance from touching the hull. The main reason I did this was to eliminate as much wet carpet in contact with the hull as possible.

I doubt there are any problems with the boat resting on the inside boards though.

[Cartes Custom]

Thanks guys, greatly appreciate you comments. I will post pics when completed.

[AllyFishing]

These are pics of my trailer taken recently while on vacation. It annoyed me every time I looked at it sitting there knowing how bad it was, nothing I could do about it at the time and what in the heck am I going to do to fix this problem. Like Mark, I too debated extending the inner boards back a bit further, maybe a foot or 2 but not all the way back to the rear cross member.

It appears to me that the bulk of the weight of the hull is on the rear half of the bunks because of the way the carpet looks. The forward area of the carpet is much cleaner and less worn. As it is now my hull rests on the roller at the rear of the inner boards because the roller is white from gel. And it is resting on the inner boards as indicated by the way the carpet is crushed so if I wanted to distribute the weight of the hull on ALL boards then I would have to raise the inner boards first then the outer accordingly. But that would put the hull higher on the trailer.

[AllyFishing]

I use tinypic and don't know how to rotate a pic before it is uploaded.

[fishnfireman]

Definitely want the hull off the roller. Both of mine were like that after one season.. Had to cut and re-weld the brackets on this one.
Slide a credit card between the hull and bunks to check for even wt distribution. No doubt yours is carrying most of the wt on rear of boards but a lot of the visible carpet wear is from loading.
The boat will sit a little higher on the trailer if you shim all the boards -- however my bow roller was still in alignment.
As for the wt being carried on the outside bunks...............I figure 90 % of our boats that get hauled much --have wt on the inner boards..
The only way to keep those outer boards from settling over time is to put a shim between the bottom and the frame.
Or If your replacing boards do as Catfish and use a 2 by 8.

Also in your case if you raise the boards it might be enough to clear the roller.
I'm still not sure about extending the center boards -- My thought is the long deep keel on these boats will hit them when loading and pop the nose up..

[Cartes Custom]

Those pics make me more convenience to increase the length of the center bunks all the way past the rear most cross member. I’m traveling again but upon return will place some bunks for a look and then post pics for opinions.

[revlimiter]

These are pics of my trailer taken recently while on vacation. It annoyed me every time I looked at it sitting there knowing how bad it was, nothing I could do about it at the time and what in the heck am I going to do to fix this problem. Like Mark, I too debated extending the inner boards back a bit further, maybe a foot or 2 but not all the way back to the rear cross member.

It appears to me that the bulk of the weight of the hull is on the rear half of the bunks because of the way the carpet looks. The forward area of the carpet is much cleaner and less worn. As it is now my hull rests on the roller at the rear of the inner boards because the roller is white from gel. And it is resting on the inner boards as indicated by the way the carpet is crushed so if I wanted to distribute the weight of the hull on ALL boards then I would have to raise the inner boards first then the outer accordingly. But that would put the hull higher on the trailer.

Is that from the boat in your signature? I figured Allison would have had that figured out by now, trailer fitment seems to have always been an issue with them. That's pretty poor for a top of the line rig that's only 5 years old. Hard to believe this is even a discussion for what these things cost. Good luck with it!

[catfish123]

Those pics make me more convenience to increase the length of the center bunks all the way past the rear most cross member. I’m traveling again but upon return will place some bunks for a look and then post pics for opinions.

I believe if you get the boat up off the "center", guide bunks altogether like it is supposed to be, there will be no need to lengthen them. This has worked well on my XB 2003 and it appears the trailer's "shortcomings" are the same on the 21 footers.

[AllyFishing]

revlimiter yes this is my 2013.

I have raised the outer vertical boards once already and inserted shims between the frame and the bottom of the board but they still sagged or shrank or something enough to put the hull back down on the inner boards and rollers again.

This outer board problem of not maintaining proper clearance off the inner boards and rollers is what has me leaning toward replacing the outer vertical boards with some sort of composite material like ultimate bunk boards. something that wont shrink or rot or sag. I think that is what Mark istrying to accomplish with his thoughts of using metal

[Props4u2]

Darris designed the trailer so that all of the boat weight is on the outer bunks, that doesn't mean the trailer company is getting it right unfortunately.
The bunks do need a notch in the rear where the hull has a slight lip, I don't know why that isn't done when the trailer is built.

As stated the outer bunks should be high enough to raise the hull above the rollers, they are only there for loading purposes. The hull should not be supported by the bottom guide bunks, there should be a gap between those bunks and the hull when it is adjusted correctly. The boats main stringers are over top of the outer bunks so the hull is resting on it's strongest point when everything is correct.

[Johnny Maxwell]

I am in the same field as those who say that it is dangerous to trust the trailer makers with getting everything perfect so the boat has the absolute best contact with the hull. On several boats that I have owned I have had to put the boat in the water, dock it up, and rework the supports and vertical supports so as to give as much support as I can get out of them. I have also had to cut off and re-attache guides and roller carriers too. An idea that I wish somebody would look into is why would there not be a better support using multiple short supports (same lines as the vertical support beams) and have these short members on an air shock extension. The reason I think this would work best is a long horizontal 2X6 with carpet is fixed and can't possibly give contact support from front to back. The boats don't have a exactly level surface, and they bounce, and....over time the compression on the carpet lowers the boat on the trailer. My idea may not fly but I'd love to know that on the ride home I could raise the vertical bunks up about 1/4" or so and get the same pressure at every contact point on the hull. As it is, I don't have time to try this so you guys build it, prove it works, and they will come. LOL

[AllyFishing]

Wait a minute.......you saying the hull surface resting on the outer boards is not straight like the board?? Straight meaning in full equal contact from front of board to end of board?

[white gambler]

Hate hearing this. I've had 7 gamblers and I could always find a few things about the trailers that left me unimpressed. Ameritrail builds them. Poor Bunk fittament, winch not being centered, fenders hung uneven, backing board that was rubbing the inside walls of tires (they were notorious for that particular thing) The only time I remember being very satisfied with a trailer is when I had one built for my older gambler 2100 several years ago. Ameritrail picked up my boat, took it to there shop in Florida and built a c channel aluminum trailer custom fit for that boat. Other than the crooked fenders which I re mounted, that trailer fit that boat like a dream. I will say they gave me great customer service which seems harder and harder to find. I'm wondering after reading this if the only way to get a truly good fitting trailer is for the trailer mfg to have the boat at their place and build it right underneath the boat as it's up in the air on a sling? I just hope I'm not real disappointed in the one boatmate builds for my Allison. Curious to see what cartes custom does with his in term of modifications

[catfish123]

Wait a minute.......you saying the hull surface resting on the outer boards is not straight like the board?? Straight meaning in full equal contact from front of board to end of board?

Confused too like you Craig. When I hear "horizontal" boards, I am not thinking of the outer bunks which I consider to be vertical. On my XB 2003 it would appear that where the rather short, outer vertical boards touch the hull, the surface is pretty flat if not perfectly flat? After adjusting mine by adding a height extension to the winch, putting in 2 x8's and notching them so the bottom rests on the frame, I now can see daylight all the way under the guide bunks from front to back.

[AllyFishing]

white gambler, don't be afraid to buy an Allison based on what I or others are saying here about the trailers. Not every one I know has had an issue like some of these here. I firmly believe that Allison is now working on getting their hulls setting on the trailer properly. The discussions here are not slamming Allison. We as a group are most interested in coming together for the good of the company and with our input and bringing to light the problems most of us have or have had with the fit of the hull on the trailer I'm confident this will be resolved in the future.

[hooken203]

Yep remember the day several of us surrounded Darris and told him the the coolers in the pros sucked? Well they fixed it mine makes ice now.

[white gambler]

white gambler, don't be afraid to buy an Allison based on what I or others are saying here about the trailers. Not every one I know has had an issue like some of these here. I firmly believe that Allison is now working on getting their hulls setting on the trailer properly. The discussions here are not slamming Allison. We as a group are most interested in coming together for the good of the company and with our input and bringing to light the problems most of us have or have had with the fit of the hull on the trailer I'm confident this will be resolved in the future.

To late for that one my end, hehe, I'm committed, and am fairly confident I will like the boat. I just hope i don't hate the trailer.

[TB21]

I must be the lucky one I guess........With both of the 21' Allison's I've had the trailer fitment was perfect , no complaints at all. I just don't get trying to re-invent the wheel but , I've also not had one ounce of problem with the Allison installed jack plate.