I actually have a great relationship with my kids' dad, but I strongly disagree with him about buying the kids expensive cars (both have totalled their cars), and various other ways in which he gives them what I think they should be earning.
HOWEVER, I have decided that what he gives them or spends on them or helps them out with is really not my business. I've expressed my opinion, but the bottom line is that he has his own relationship with them, while I have mine.
I doubt that it will ruin your daughter (or the other kids) for him to give her the canoe. My older son commented to me a couple of years ago that he sort of appreciated the fact that I often say "no" to things.
Personally, I think making it into a power struggle does more harm than his giving her the canoe will.
Just my two cents...