That is a mighty big boat for a 45# cylinder anchor!! If you're trying to anchor in the main current, you might want to go to an anchor of rocking chair stlye, with 2-3 long tines. If the river is of gravel bottom this will hold a lot better than what you have. If the river is full of snags I would not use this style anchor, you may lose it. If you need a photo, let me know via e-mail, and I'll send you a photo of my anchor.