Re: trailer winch arm
I think what jeeperman was getting at is it doesn't appear that trailer was designed for that boat.
From what I see in the picture:
The bow roller needs to be above the bow eye like jeeperman said.
The bow roller needs to be higher in relation to the winch.
The winch strap should pass under the bow roller to attach to the bow eye. I don't think the winch is backward since the handle is on the left side.
It looks like even with the boat winched as far as possible, the bow will not contact the bow roller. You'll need to lengthen the arms the hold the bow roller at least.
If you cannot get the winch strap to go under the bow roller and still pull somewhat horizontal, you should at least use an additional strap (like a ratchet kind) to secure the bow down to the trailer.