From an engineering perspective there’s something about Shoal Waters’ road trailer that bothers me. In fact, I’d go as far as to say that it is at least bad practise if not just plain wrong.
Here’s the trailer put out of the way temporarily whilst I try to find space for it in the hay barn. Can you see what bother’s me?
Here’s a closer look at what I consider to be the problem. The cross beam is welded to the wrong side of the side beams. It’s underneath.
The intermediate beams are the same except that they are not welded but use U-Bolts. But they are underneath the side frame. See how rusted that U-Bolt has become? The weight of the hull is being taken but this and the other U-Bolts, not a good place to be.
The cross beam at the rear is also welded and also underneath.
So why do I consider this to be an issue? Simply put, the entire mass of the boat and the strain of it bouncing up and down as the boat is transported from A to B is on the welds and the U-Bolts. I would have designed this with the cross beams on the top of the side beams. In this case the welds would only serve to increase the rigidity of the frame and the U-Bolts would only be there to stop the beams from moving around on the frame. The weight and stresses would be taken by the beams directly.
Now I can see two reasons why this might have been designed this way. The first is that if the intermediate beams are put on top of the side beams, the the U-Bolts would be the other way up and the nuts and protruding bolts would sticking up, rather than down and that might be considered to be a hazard. Secondly, by placing the cross beams underneath, the height of the boat above the trailer is reduced by 60mm. Is that significant? I don’t really think so.
Still, whatever the reason for the design decision, I’m going to change it so that the beams are where I think they should be. I’ll not removed the welded beams, they are there to make the frame rigid but two new beams will be sourced and mounted close by them, but on the top of the side frames.
Now, this trailer is never going to be road worthy, it’s too rusted for that, but over the next few years a boat will be put on and taken off the trailer at least four times a year and I need to make that as painless as possible. That means a beam under the hull but over the trailer and wide enough to get the trailer out just be pulling it and not by going through the hassle we did previously. Right now, the boat is so low that this isn’t possible. By placing the offending cross beams on top of the side frame and by raising the rollers as high as they will go, there will be ample room to put the beam in place and thus create the required bridge. The down side is that Shoal Waters will be higher and thus slightly more difficult to get into. I’ll just have to lose some more weight and start stretching to increase my flexibility.
So that’s what I’ll do.
Obviously, photos and posts to follow as this progresses. Shoal Waters needs to be moved into shelter of the hay barn as soon as possible.
Time for a cup of tea.