No. 4 – A Painted tubular steel frame on a salt water boat trailer is a mistake

Tubular steel trailer

A trailer made with tubular galvanized steel

Boat trailers made of tubular steel or aluminum are fairly popular, especially on mid- to lower-priced boats. But tubular metal frames have two fundamental problems in salt water:

  1. You can’t see inside the frame to inspect for rust or other problems
  2. You can’t easily rinse the inside of the frame tubes

If the frame is galvanized steel or aluminum, this may not be a problem. However, painted tubular steel is a different story. Trailers built with painted tubular steel are popular on freshwater boats, and their owners may be tempted to venture out into bays or near-coastal waters for the occasional salt water trip.

Toy Boat 1, which was an aluminum bass boat, had such a trailer. We made the mistake of taking it into the waters of San Diego Bay early on. We took the boat to a local lake the next day, thinking that dunking the trailer in fresh water would be enough to rinse it out.

Not a chance. Within a year, we discovered that a number of welds were nearly rusted thru from the inside. Things were so bad that the trailer actually came apart when raised on a lift at a welding shop. 

Open (“C”) channel or I-Beam galvanized steel or aluminum are the time-tested choices for salt water boat trailers. This type of construction allows welds and joints to be instantly inspected. In fact, with this kind of construction, even a painted frame can be used successfully in salt water.

Our very first salt water skiff was carried on a painted open-channel steel trailer. Painted flat black, we used it for quite a while, entirely in salt water. The trick was to inspect the trailer after every launch. At the first sign of corrosion, we cleaned off the rust with a wire brush, then primed and repainted it on-the-spot. The flat black was an easy color match.