Roller trailer for bluebill?

P

Paul W

Well-known member
Roller trailer for bluebill? Will this work or is a bunk trailer better for these ply boats?
 
I have a half roller / half bunk trailer for my bbIII and have not experienced and trouble with the rollers, other than they do leave black marks on the boat though that I don't care for. It is a 80's trailer and I bet if I replaced the rollers it might fix the black marks on the boat.
 
A few years back I spoke with the gent that made the Estuary boats. He sold those boats with roller trailers...one reason was for launch and retrieve without having to submerge the trailer as far into the water....it's a thought however not as serious of a consideration in fresh water as it is in salt water.
 
Paul, the decision is primarily based on the hull shape, and the hull construction. A roller trailer works great on a displacement hull as it better cradles the hull. I had one for my BBSB until it rusted out and failed on Long Island this past January. I now have a bunk trailer, but the bunks are supported far apart which allows the bunks to conform to the hull. I think it will work fine for me.

A planning hull can easily use bunks since there is significant contact/support area. Bunks are cheaper, and easier to maintain. Rollers are so easy to load and unload, and do a great job of self centering, but generally decrease the contact area, and in the case of fiberglass boats can lead to divots in the hull. In all cases proper postioning and maximizing contact areas will be best for the boat in the long haul.
 
I don't know about plywood but I use a jet ski trailer with bunks for my aluminum blue bill. Its a fairly light boat so its easy to launch and load. either should work well for you.
 
Dave is right; the divots are a primary concern for any type of boat construction. If you use rollers and the boat has any weight at all the rollers ought to support the boat along the keel or stringers.
 
I think it is important to do a little math when you look at how well the boat is supported.... for example, my BBSB, was ~350lbs then add the motor, anchors, gas, stuff... I bet I was closer to 800lbs on the trailer. On the rollers, there were 12 rollers, maybe 36 inches of total contact area! 22lbs per square inch. On the current trailer, I have full contact of the bunks for about 8ft, which I estimate at about 576 square inches of contact, for less than a 1.5 lbs per square inch. Now my numbers are not exact, but the correlation is what is significant. Rollers need to be on a stiff, tough hull able to support the localized pressures. My BBSB was way over built, and I am reminded of that everytime I need to pull it out of the mud!

With a planing hull, bunks for sure in my opinion. Especially on a small duck boat where there is not so much weight and it will be easy to winch up.
 
On the current trailer, I have full contact of the bunks for about 8ft, which I estimate at about 576 square inches of contact, for less than a 1.5 lbs per square inch.
Click to expand...
(taken out of context)
Dave,
In my experience "full contact" does not usually equate to "full support". In an earlier post you mentioned that your bunks were supported near each end and that the board flexed to conform to the hull.
In theory, the board will continue to flex until either;
(a) the wood will not flex any more due to the strength of the board (at which time the center of the board may be carrying more load than the ends)
(b) the boat comes into contact with the board at the point that the board is supported to the trailer (at this time the load may be concentrated on the support points and not much carried by the flexed board in the middle)
I will concede that the bunks, even if not equally supporting along it's entire length, tend to spread the contact points over a longer/larger area than the rollers. A lot of roller trailers are using more numbers of rollers to address that concern.
 
Dave,
In my experience "full contact" does not usually equate to "full support". In an earlier post you mentioned that your bunks were supported near each end and that the board flexed to conform to the hull.
In theory, the board will continue to flex until either;
(a) the wood will not flex any more due to the strength of the board (at which time the center of the board may be carrying more load than the ends)
(b) the boat comes into contact with the board at the point that the board is supported to the trailer (at this time the load may be concentrated on the support points and not much carried by the flexed board in the middle)
I will concede that the bunks, even if not equally supporting along it's entire length, tend to spread the contact points over a longer/larger area than the rollers. A lot of roller trailers are using more numbers of rollers to address that concern.
Click to expand...
Dave, you are correct, and my explaination maybe too general, and to use a displacement hull is a poor example. A planing hull that has a long straight section, and bunks properly fitted and supported along that length is the best situation for the hull. Another point that I think gets missed for many folks when fitting a trailer properly is how the bunks or rollers support the transom, or where the loads are on the hull. I see many boats trailered with the bunks ending short of the transom, sometimes by more than a couple inches. I like the bunk supports to align with the transom and have the bunks extend a few inches (makes a great step!). And then I add a transom saver too! But that is the engineer in me... I tend to over think and over build!
 
You must log in or register to reply here.
Back
Top