First -- yes I have used the search function

New to us Donzi 33zx on a Nextrail aluminum bolt together trailer. The main bunks are nominal 4x12x14' and are an open grain wood like red oak. They are rotten and splitting in what 'good' wood is left. Surprisingly, it has been challenging to find wood this size. Even local sawmills are not interested in a small job like this ...

Considering laminating two untreated doug fir 2x12s to make a single beam. Will use quality construction adhesive, a 'pattern of screws and through-bolts at 4 mounting points along length of bunk. Top edge will be cut to match 22 deg deadrise and notched to conform to steps. Trailer also has four 2x6s along keel.

Anyone see a problem with this approach to the 'main' bunks?

thanks in advance!

Do you need the boat to be that high on trailer? If not, i use a single 2x6 and it gets the job done!

I don't see any reason you can't do that. If your trailer was like my aluminum Owens & Son's, the bunks you referring to probably sit on the I-Beams near the fenders and you need them that tall for the boat to safely clear the fenders.

We hold houses up with bolted together beams, I don't see an issue with a boat.
Look into FastenMaster Headlok structural screws, they sit flush on the beam and are rated structurally. I'd also make sure they're rated for salt water, not sure where you're located but something to look into. I'd also screw into the beam from both sides.

Griff -- the main bunk supports are essentially flat iron with a flange to u-bolt to cross braces but yes, they get the boat high enough to clear fender overhang.

Indy -- good copy on the structurally rated screws, will check them out.

thanks for the replies!

Here u go hope this helps
MENARDS

I'm pretty sure it was Smoot Lumber (now owned by BMC) that I bought some custom timbers from years ago when I was in NoVA. I was able to order two 4" wide vertical bunks to replace the crap that was on my Rocket trailer. I think they were 4"x10" and however many feet long.
https://www.buildwithbmc.com/bmc/s/m...k-capabilities

The problem with the lumber that Rocket put on there is they were through-bolted, and suspended above the trailer frame by 2-3". When I rebuilt the trailer, I added supports so the wood was resting on the trailer frame, and through bolts where only holding it in place.

That said, I don't think you would have a problem with laminated 2xWhatever. Just make sure you take a look at improving the setup if you can.

Also check here:
http://www.colonialhardwoods.com/beams-and-timbers/

And there are some places in Richmond that can probably accommodate and not be in NoVA price gouging territory as well.

http://www.ruffin-payne.com/lumber-product/lumber
https://transitlumber.com/products.htm
https://goodwynlumber.com/departments/2810/lumber
http://www.siewers.com/

Sydwayz -- thanks for the links ... Smoot has been recommended a few times, maybe I just talked to the wrong person when I called .

Your old rocket setup sounds similar; the main beams/bunks are vertical and elevated a few inches, while not through bolted for support they are 'resting' on top of through-bolts in the supports.

Yep, mine was EXACTLY like that. Notice the weight of the boat and the angle of the dangle is also pushing your main supports out. I've seen those collapse on other trailers and create significant hull damage.
Later trailer manufacturers have been adding an outboard support strap down to the cross member, to keep those brackets supported to stay vertical. I would highly recommend such for you. You do have the lower V-bunk which is awesome. I didn't have that on mine.

I replaced mine with the same lumber, but I also custom cut pieces of wood to fill that gap between the cross members and the wood. That way the bolts were not holding the load.