[willy]

Good info from both guys here, dual axle is the way to go if you can afford it. These boats were sold original with single axles so it is definetly doable, especially short run and storage being main use. Bearings taking a serious working every time used though and there life will be shorter and therefore more frequent maintenance.
Other major consideration is wether it is aluminum or galvanized, both are good but remember galvanized trailers rust and corrode away from inside so check it good, can look pretty outside but be paper thin ;)