For inevitable on-the-road problems, a spare parts and tool kit is essential. Our trailering experts recommend traveling with a box filled with extra grease, bearings, and a grease gun that works with Zerk fittings. They also recommend carrying hydraulic jacks, one spare wheel assembly with a mounted tire, and a few unmounted tires. An entire axle assembly, complete with a wheel and a tire, can be a crucial backup. Here are a few of their must-have items that will ensure your boat gets to its next regatta in one piece.