Boat trailers come in many varieties, so there are many decisions you need to make when purchasing a boat trailer. We’ve covered some topics already, such as “bunks versus rollers” (boatingmag.com/boat-trailer-buying-tips). This time, we’re presenting some key points you should look for when deciding which metal your new boat trailer should be made from.
Painted steel trailers are excellent for freshwater use, but they readily corrode in salt or brackish water and are best avoided for those uses. Painted trailers often feature custom paint colors matched to the boat. Steel is quite strong, and, corrosion aside, a painted trailer is as strong as a galvanized trailer.
Corrosion Resistance: Fair
Galvanization is a zinc coating applied over steel. This provides tremendous resistance to corrosion, although rust will win out eventually because the zinc is simply sacrificial. It’s good practice to rinse a galvanized trailer — or any trailer used in a marine environment — with fresh water after each launch or load.
Cost: Middle of the road
Corrosion Resistance: Good
Aluminum trailers resist corrosion fabulously and work well in marine environments. They do corrode, but the oxidation appears powdery white. They can be lighter than steel trailers of similar capacities, which can increase fuel economy and assist in maximizing tow-vehicle capacity, but compare to be sure.
Corrosion Resistance: Best
Five Trailer Maintenance Tips Regardless of the metal from which your trailer is made, it will need maintenance. Use these tips to extend the life of your boat’s trailer and enhance its performance.
 Rinse your trailer with fresh water after every use and periodically wash it with soap and water.
 Keep a can of color-matched paint or cold galvanizing spray on hand and coat over scratches, chips and rust spots as soon as you notice them.
 Apply dielectric grease to the sockets of any incandescent light fixtures to stave off corrosion.
 Protect the trailer tires from prolonged exposure to direct sunlight, which will degrade them, by using dedicated tire covers or pieces of tarp cut to size.
 Grease shafts and roller assemblies of roller trailers at least once per year.