Structural query about the new trailer for my Picton 170 GTS.....
I'm 99.9% of the way there but just need someone to reassure me that 80mm x 40mm x 3mm (wall) of mild steel box section will be sufficient for the new braked axle roller coaster trailer I'm building for my Picton 170 speedboat? I'm also planning to run some 40mm x 40mm x 2mm (wall) mild steel box section along the top to help with the longitudinal forces.
The axle is rated to 1300kg so won't be putting any more than 1000kg on the frame at most. Having had a look at any boat trailer I've come across recently, it seems that for the most part that 80x40 is a popular choice.
Also, any thoughts about whether or not its best for each set of rollers to tilt freely on the beams as well as the beam swinging??
Thanks for those photos Trailer Guy. Yes just like the first photo, but like you say, with one axle. Looks like they've gone for 80x40 for the lower part of the chassis and 60x40(?) for the upper part? I don't need to go as heavy duty as that and am planning 40x40 with a 2mm wall for the upper part. That should be sufficient I feel.
Good point about the rollers. Some swing beams I've seen just have the roller assemblies fixed so that the only movement the roller has is in the transverse direction. But I guess having each assembly pivot on the beam itself adds to the flexibility. As it's a small boat, think I'll go for 2-3 pairs of rollers each side at the back and 2 pairs at the front, so it will look a bit different to the layout you've got there. Should hopefully be able to get away with just the single point pivot between the swing beam attachment bracket and roller arm assembly. Planning to "U-bolt" some keel rollers to the beams as well.
Do you have any pictures for the mechanism that fixes the swing beam to the chassis at all mate?