Quick que?tion about a unique way of using a strap.

Where are the pictures?

 

I was told a long time ago. Right or wrong not sure. The rub rail is not a rated point of attachment. I try not to use it for an anchor. I use the spools, stake pockets and the underside of the winch rail. Going thru boards, not sure what you mean. Where you put your straps, use wear protection.
I use the rule. When in doubt, tie-down different or add more straps, chains. That gut feeling is usually right.

 

Im a visual person... not sure what youre trying to say.

 

No way hooking to the actual rub rail is gonna fly , unless your trailer manufacture has a rating posted on the trailer for such an attachment , as far as between the boards I figure your deck has slits between the decking boards ? I would be Leary of this as well , it may very well be secure but , generally the deck boards are not to be used as they can split, splinter or come loose they are held in place with relatively small screws and are designed to support weight setting directly above , I saw a load once where a guy had a chain running over his outrigger deck board and tied to the d ring, when the load shifted , well it was ugly and dangerous, if I read what u said correctly , the board could lift or break, , why not just go over the rail and attach to under rail or better yet pockets, setting the straps wider will reduce the down force on a "fragile " load , also the straps are not required to be symmetrical , if the load is off center the straps will not bebut can still be safe and legal.

 

Most likely it is (Given I pictured it right) but who cares?, the important thing is that you don't feel good about it.