I am just in the midst of designing a deck I can put over the boat when trailering so I can take the following:
2 - Dirt Bikes
1 - ATV
3 - Mountain Bikes
Some camping gear.
My trailer is tandem axle with 3700lbs rating each.
My boat is 3000lbs. So I am assuming as long as I have the weight centered over the axles that I should be okay with an additional 1200lbs.
My idea is to build a light weight (frame with mesh)deck. That can be easily lifted by two people. Back mounts will slid onto boat guides and I will make similar boat guide posts in front of the axles... Quick release pins... and some long ramps.
Then when I go camping... I can take the camper... and all the toys...
To avoid modifying the trailer... I will use u-bolts etc... to add the new boat guide mounts.
Visually... it looks like it will work no problem... since the atv/dirt bikes will be sitting directly over the axles.
I would love to do something like in the picture.. but the wakeboard tower is the issue.