Throw A Coat On: Boat Trailer Rust Prevention

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The ocean is a harsh environment for boats and boat trailers. While some are constructed from rust-proof aluminium, the majority of boat trailers are made from steel, which is not known for its marine rust protection capabilities. We look at the best products and methods used in boat trailer rust prevention.

Why use steel if it rusts?

Steel is the ideal material to be used for heavy loads – it is stronger, more rigid and more resilient than aluminium. Importantly, steel is a cheaper material because it’s easier to work with and more plentiful.

Most new steel trailers are hot-dip galvanised. This is just a fancy way of saying the steel is dipped in molten zinc. However, the galvanised layer will eventually perish, especially if the trailer is used often.

Fish oil

An excellent and cost-effective way of prolonging the life of a new galvanised trailer is by adding a coating of fish oil. Fortunately, it’s sold deodourised and is one of the cheapest marine rust protection products you can get.

Fish oil comes in tins and aerosol cans for hard-to-reach places such as inside tubes, and it’s suitable for being fully submerged in water. Fish oil is also suitable for older boat trailers that might have existing rust. It can penetrate rust and halt the process of more rust developing.

However, one of the downsides is that it remains tacky and can become unsightly when it collects sand. And if you’re a regular boat tower, you will probably need to top up your supply annually.


Lanolin is water, salt and acid-resistant and is a good, light-duty lubricant. Coming from sheep’s wool, lanolin is biodegradable and a natural alternative to petroleum-based marine rust protection.

It’s available in paintable or spray-on forms, or as a grease which can be applied to difficult areas. At $20 for a 1kg tub of lanolin grease , it’s also very inexpensive.


Tectyl is a petroleum-based corrosion-preventative compound designed to military specification. Available in aerosol form for about $17, it uses a petroleum wax carrier that sets in a waxy orange coating.

Tectyl’s rust prevention powers last for up to five years so you won’t have to top it up annually like you might with fish oil. However, heavy trailer users should give their trailer a once-over more frequently – every couple years should do it.

Aerosol zinc

For really hard-to-get-at places and for componentry such as bolts, nuts and springs, this spray-on zinc coating is hard to beat. The mixture is 93 per cent zinc and it can be welded or powder coated once it has set.

Disc brakes

Disc brakes are more corrosion resistant than drum brakes by virtue of their open design. By comparison, there are few areas where moisture can pool on disc brakes.

These are just a few rust prevention options that come highly recommended. These and many others are available at a retailer near you.

Learn more about disc brake options for your boat trailer.


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