Boat Maintenance - Trailer

Trailer Winches

Boat Maintenance – Trailer

If you’re unlucky enough to have access to a boat slip or somewhere close to the water, trailers are essential for transporting your vessel to the water. Any faults or problems can affect its ability to handle the boat during transportation and can endanger both you and your family, and the others around you. Trailer maintenance and regular inspection are imperative, which is why we’ve created this simple checklist to ensure you and your boat are safe as you go to and from the water.


Wheels and Bearings

Ensure that when the swing-up jockey wheel is swiveled from the horizontal position to vertical, the spring-loaded handle and extension pins lock securely into both holes in the jockey wheel mounting plate. Lubricate regularly to keep rust away. It's always a good idea to swing the jockey wheel away from the vehicle so that there woill be no drag on the trailer if the wheel comes unstuck at any point.

Check wheel bearings within the first 10-50 kilometres of using the trailer. Servicing wheel bearings should be done every six months for regularly used boat trailers. If the wheel does not rotate on the axle smoothly then you will need to replace the bearings and this should be carried out by an authorised mechanic. It is good practice to get the trailer checked by a mechanic every six months to avoid expensive on-road costs.

Bearing protectors are designed to keep water out of the bearing hub when you drive the trailer into the water when launching or retrieving your boat. The ideal time that you should grease the bearing protectors is prior to putting the trailer in the water so as to end up in a situation where you have a hot hub with liquid grease in the hub.

Taking the trailer with a hot hub into cold water will allow a small amount of water to seep in through the rear seal of the hub, causing damage to the bearings when driving down the road. Pumping grease into the hot hub prior to entering water will cool down the hub, and pack the hub with solid grease like Bel-Ray Waterproof Grease or Lubrimatic Trailer Grease to eliminate any possibility of water entering the hub.

Marine Trailer Wheel Bearing Kits Trailer Wheel Bearing "Mates" Protector



The two main adjustments are the keel and wobble rollers. Keel rollers are adjustable in the vertical plane (up and down) to suit the keel shape of your boat. The strongest part of the boat is the keel and keel rollers are designed to take 85 to 90 percent of the boat weight.

The wobble rollers have both vertical and horizontal adjustments and serve two purposes; to keep the boat stable and sitting upright on the trailer, and to guide your boat on and off the trailer.

See Thru 8" Keel Roller Heavy Duty Wobble Roller


Tyres and Pressure

Check tyre pressure and inflate to the correct pressure, usually around 45 to 55 PSI, depending on the weight of the boat-trailer combination. Regularly check for the correct inflation pressure as well as any uneven wear on the tyres. Tyre rotation should be carried out every six or twelve months depending on trailer use.



Ensure your trailer plugs aren’t affected by moisture and corrosion and replace if so. If you have a new trailer with a different connection, attain a trailer adaptor to suit the correct amount of pins in the connection.

Any trailer with blinking or dim lights usually means the wiring connections will be twisted together and insulated with electrical tape or connected via automotive-style crimp connectors which can’t handle the vibration and moisture. Use solder and PVC shrink tube on the connections and then smear a film of dielectric grease on the hitch connectors to prevent moisture from corroding the pins.

Trailer Plugs Trailer Adaptors



The trailer brakes should be checked within the first 10 to 50 kilometres of using the trailer and every six months after that. Brake adjustment for the mechanical over-ride system can be adjusted at the front pulley or the adjustment bolt on the callipers. Remember to leave enough slack in the cable to allow for the flex in the trailer while under tow.

Lubrimatic Trailer Grease is excellent for protection against salt water, salty air and atmospheric chemicals and can be used on the disc brakes to prevent corrosion.



Inspect your trailer for cracks or severely rusted areas that may have become potentially brittle. This includes your springs and axles. Each time you take your boat in and out of the water, you are introducing your trailer to the salt water of the sea/bay. Make sure you give your trailer a proper clean after each use to avoid rusting and corrosion and help add to the safety and lifespan of your trailer.



Check the coupling for any signs of rust and wear. On an older trailer it’s probably the standard ball mount version but if it is due for replacement, consider swapping it for a system that’s better suited to the way you will use your boat trailer, such as over-ride brake or off-road coupling.

Consider investing in a trailer lock for use when you’re car and trailer are parked or if you’re leaving your trailer anywhere unsupervised. The trailer lock expands to prevent uncoupling from your vehicle and is activated via a simple key lock.

Trailer Coupling Trailer Cop Trailer Lock


Chains and Shackles

Australia-wide, safety chains are required as part of the towing mechanism on your trailer. They connect the trailer’s A-frame, or drawbar, to the main tow-bar framework of the towing vehicle using D or bow shackles.

As a safety device, the chains, and consequently the shackles, must be strong enough to keep the trailer connected to the towing vehicle and prevent the drawbar from touching the ground if the coupling should break or become disconnected from the tow ball.

The Caravan Industry Association of Australia recommends shackles meeting the AS 2741-2002 standard be used to secure rated safety chains up to 3500kg capacity. In addition, they recommend that shackles should also have the following characteristics:

  • The shackle grade is “S” or “6”
  • The working load limit is 1000kg
  • The shackle diameter is 10mm
  • Either a bow or D shackle may be used


Tie Downs

There is a tie point at the front of the trailer at the base of the winch post to tie the front of the boat to the trailer. The other tie points are on the side or at the rear of the trailer and these require a long ratchet strap. The strap goes over the rear of the boat from one side to the other.

Tighten the strap to anchor the rear of the boat before attaching the safety chain under the winch to the front of the boat. It should be noted that the winch is only there to retrieve the boat, not to anchor it to the trailer.

Tie-Down General Purpose Tie-Down Medium Duty Cam Buckle



Check for cracked wiring and damaged lenses every six months and ensure all functions of the lamps are working. Clean the plug and socket with electrical contact cleaner and a fine wire brush.

A trailer that’s constantly being dunked in seawater needs submersible tail lights sealed against leakage and condensation on rust-resistant stainless steel mountings.

LED Submersible Trailer Light Combo Submersible Trailer Light



Boat trailers must be registered in every state in Australia. Registration services for light trailers are offered at transport and motoring customer service centres. To find the one closest to you, contact your local department of transport.

That's been our maintenance blog series! Stay tuned as we'll be bring you more helpful and interesting reads in the future on all things boating!


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