Another Bunk Question...

[bunker108]

Tomorrow I am starting the conversion on my trailer from a roller to bunk set up for an aluminum 18ft Starcraft SS.

My plan...

Two 2X6 bunks around 10' long supported by three trailer crossmembers. Those will support from under the transom up to where the hull starts curving up.
The front crossmember will get a keel roller. Should I add one to the rear crossmember too?
The winch tower has a hull stop on it.
Does this set-up sound sufficient?

Bunk carpeting question...

Will it be ok to precarpet the bunks and then just sink the carraige bolt below the surface. Do I need to seal the exposed heads? Or can I install and sink the carrige bolts and then carpet over the top of them?

I am leaning towards the last method but installation could be done quicker installing the bolts through the preinstalled carpet. I just wanted some opinions.

Thanks!

 

[Evinbuck]

Re: Another Bunk Question...

I recently converted my trailer from roller to bunks and essentially done about the same thing as you're doing. My boat is 17-1/2' and I made my bunks about 9-1/2' over three cross members. I put a keel roller front and back.....back just for the off chance the keel might scrape on some ramps. I used galvanized carriage bolts installed first (under the carpet). I made sure they were aligned with the brackets before installing the carpet. I used pressure treated lumber by choice and that is why the galvanized bolts. Also I put a gasket-like material wherever the pressure treated lumber touched steel to prevent corrosion. Actually that is a bit over-stated because it would take years for the pressure treatment to cause dangerous corrosion results. Not even close to everyday salt water useage. Anyway, you should be good to go with your plan as my trailer works great. You may need to tweak adjustments or experiment how far to dunk the trailer but it will work.

 

[fibersport]

Re: Another Bunk Question...

I modified a bass boat trailer to fit my Century inboard, like you are planning, the bunks are supported by three cross members. I spaced them so that they match my stringers, the cross members are slightly v-shape and I do not use rollers, have never scrapped the hull either. I re-used the bunks and had to relocate them to fit, the carriage bolts were installed before the carpet. Since mine is an inboard, I had to notch the rear cross member so that my prop would clear. I would strongly suggest that you add side guide bunks as I did hit the prop once, the side guides went on before the next launch. In my two boats and three trailers, I have never had an easier loading trailer. I am able to drive right up and power to the winch stand. As long as you don't put it too deep in the water, the side guides help quite a bit for me. My previous trailer was an EZ-Loader, it loaded great but due to my flat bottom hull, it was putting too much stress on in towards the bow and was causing dimples in the glass. The long bunks, about 10 ft in my case support the hull like a factory cradle. Mine also has outer bunks to help support the chine as well. Good luck on your project.