I hate hardware store ratchet straps with a passion. I use this kind of gunwale tie down strap:
Boat Gunwale Tie-Down Strap, 13' x 2" Web #15221-7 I also make sure I have a proper chain hook for the bow eye, just in case. Many trailering how-to articles recommend two gunwale straps, angled at opposing angles such that the boat cannot move forward or backward on the trailer. Guys that trailer runabouts frequently do this, because we've all seen those horrorshow pictures of boats on the back of pickups, or sliding off onto the road. Plus, if one of you gunwale straps were to break, you'd still have a second on there.
When I strap a small boat to a trailer, or my dinghy or kayaks to the roof rack (or a load of wood to build said dinghy or kayak to the roof rack,) I use webbing cam buckle straps, looped around the bars and over the load. In my experience, it's nigh impossible to get the typical metal hooks of a ratchet strap to hook correctly on anything except for a dedicated cargo D ring. See how much I hate ratchet straps?