Span width for boat lift posts

[MadDogMike]

I'm building a "boathouse", which is the local vernacular for a fixed dock with a roof. The dock is built, roof comes next. A friend cautioned me that I should place the roof support posts wide enough to allow me to keep boards on the rack while docking. The boat slip is 10' wide, and the builder wants to put the roof posts at the inside edge of the slip, so the span would be approximately the same 10'. Like this: https://goo.gl/photos/qGn5CwiP8x5p94m1A

I want him to put the roof support on the outside of the slip, like this: https://goo.gl/photos/Wg6bFpHcZZ47YC596

I mainly wanted the wider roof for additional shade coverage for the side of the boat. He said he can push the roof out to the edge, but then he needs to put additional posts on the inside of the slip to maintain the 10' span for structural strength to support the lift. (It's a 6500-pound lift and I have an '04 VLX.) Obviously from the pic above, other dock builders don't agree that's necessary. My friend suggests I not only go with only the one set of posts on the outside of the left side of the slip, but also push out the posts on the other side a foot or so to allow wakeboard clearance. 

I mentioned that, even with the wider posts, the lift cables would get in the way anyway. He says you can easily push the cables out of the way while pulling in, and that's easier than taking boards off the racks or rotating racks in if you have spinners. He says it drives him crazy to have to spin his racks in every time he pulls in or out, and that he can't even spin them out while docked because the boards would hit the post. 

So, whose concerns are more valid, my friend's or the builders? Seems to me that the builder could just a heavier beam to support the lift to compensate for the increased span. Thoughts?

 

 

[Technicallyabu]

This question seems like it should be asked of an engineer following the local building code.  A sketch or design drawings would go a long way in clarifying to get a reasonable answer.  The way I see it increasing the span will increase the roof dead, snow, rain, wind and seismic loads so heavier vertical and horizontal members may be required.  The boat load isn't changing though so increasing the span shouldn't affect anything other than whatever cross beams the lift is made up off.  This assumes that the outside walls carry the load of the boat lift.  Don't know how those lifts are usually setup.

 

Ideally being able to drive in with boards out be nice but of the two options you mention I find moving cables aside while docking to be much worse than spinning or removing boards.  Could be pretty difficult by yourself in windy conditions too. 

[Sixball]

My lift is 10' wide. But if I was building something from scratch I think I might go a little wider. A tower with racks might be tight. A lift cover also comes down on the sides, so pulled up my boat does not see much sun.  In the end you are paying for the job so you tell him what you want!  Easy to do it right the first time. Not so easy to go back and fix anything.