20' Foot Trailer - Bunk Width

[jfsegar]

Hi All -
Just bought a used 20' Wellcraft Cuddy Cabin (weighs roughly 2700 lbs dry) with a roller trailer. I live in TN were the tide doesn't change and the ramp I use is plenty deep enough for a bunk style trailer. I'm in the process of converting it from rollers to bunk style since there are only 16 rollers on this trailer and they are falling apart. I know everyone has their preference on roller vs bunk as I read probably hundred threads on it here - I prefer bunk. Here's my question:

The trailer only has 2 crossmembers and already has movable vertical mounts on the trailer that I can use to mount my bunks vertical. After measuring, looks like 2"x6"x10' is perfect height to clear the fenders and long enough. Would you recommend going with 2 of the boards screwed together per side giving a total width of 4" per side. Or do you think I'm ok with just the one board per side? I'm also looking at keel rollers and other items to help straighten the boat on the trailer when loading.

Thanks.

 

[UncleWillie]

Re: 20' Foot Trailer - Bunk Width

I would not recommend supporting 3000+ lbs of boat on the 2 inch faces.
I would suggest you do whatever is needed to support it on the 6" faces.

 

[Thalasso]

Re: 20' Foot Trailer - Bunk Width

These are 2 1/2 x 7 x12'6in on a vertical. They hold a 10000lb 30ft boat
2x6x10 will do it but you might need to add a x member somewhere in between. The board might develop a bend



Another shot

 

[jfsegar]

Re: 20' Foot Trailer - Bunk Width

Thanks guys. I decided to just go with 2 of them screwed together on each side just for added support. Once I actually have a chance to work on the project, I'll post some pictures.

Thalasso - Good to see they will support that much weight.

 

[haulnazz15]

Re: 20' Foot Trailer - Bunk Width

Why not just add the top-swivel bracket and lay the 2x6's flat? Something like this: Seasense Bolster Bracket 10" 50081018 - iboats.

 

[UncleWillie]

Re: 20' Foot Trailer - Bunk Width

Why not just add the top-swivel bracket and lay the 2x6's flat? Something like this: Seasense Bolster Bracket 10" 50081018 - iboats.

+1
The concern is not if the bunk will support the boat.
The 2x6 is stronger if placed vertical like the beams supporting the floor in your house.

The concern is that all the weight is concentrated in a 3 times smaller area so the forces are 3 times higher.
The friction will be the same but the pressure will be higher and the abrasion of on hull will be higher.

Placing a Horizontal 2x6 on top of the Vertical one to form a "T" beam would give the best of both worlds.
Spread the load and reduce the abrasion.

 

[jfsegar]

Re: 20' Foot Trailer - Bunk Width

Agreed. Since I only have 2 cross members is the reason for the vertical mount. I'm going to put 2 together on each side to give 4" of support. I also think I may bevel the edge to the dead rise angle of the hull. So in essence it would have roughly 4" of wood against the hull. I saw it done on another post here.

 

[haulnazz15]

Re: 20' Foot Trailer - Bunk Width

I don't understand what only "having two crossmembers" has to do with it? That link I provided would only require about $30 worth of investment for the brackets (which mount to your crossmembers), and you can then lay the 2x6 flat against the hull. It's a better solution than doubling-up boards.

 

[Fleetwin]

Re: 20' Foot Trailer - Bunk Width

I don't understand what only "having two crossmembers" has to do with it? That link I provided would only require about $30 worth of investment for the brackets (which mount to your crossmembers), and you can then lay the 2x6 flat against the hull. It's a better solution than doubling-up boards.

As I understood it, he has a fender clearance issue to deal with. With just two crossmembers, I would be more comfortable with the vertical installation of the 2 X 6's.