What you need to know before buying a boat trailer

Many Australian seafarers transport their boats to and from the water, rather than mooring. This means owning, or having access to, a reliable trailer. If you’re in the market for a boat trailer, these tips will help you choose a rig that’s right for your boat and towing needs.

Multi-roller or skid trailer?

First off, you’ll need to decide between a skid trailer and a multi-roller trailer. If your boat is made of fiberglass or has a plate-alloy hull, then a multi-roller is likely to suit best. Many multi-roller trailers have rear cradles, which help to ‘receive’ or position the bow. This also helps to align the hull.

If your boat is pressed alloy, or made with a roto-moulded plastic hull, you’ll do best with a skid trailer. Carpeted or Teflon timber skids help to reduce hull flex during transport on the road. This is because the lighter hull is typically suspended over a larger surface area.

Skid trailers are known for being more difficult to handle than multi-rollers, but with a bit of practice, you should be fine.

Aluminium, steel or plastic?

When it comes to choosing a material for your boat trailer, there are pros and cons for each.


  • Generally the most popular material for boat trailers.
  • Ideally, a steel trailer should be galvanised if it is used often in brackish or salty water.
  • Easy to paint, if you want your trailer to match your boat.
  • Painting a protective coat over the steel trailer also arguably makes it last longer.
  • Steel boat trailers are highly durable.
  • It is still important to hose the trailer down, if it has been in salty water.


  • Highly durable and lightweight.
  • They tend to be resistant to rust, just make sure the alloy is not inferior.
  • Watch out for poor welding or cracks in the welding. Cracked welding is often caused by persistent flexing.
  • You may like to choose a manufacturer that bolts the whole trailer into one piece, as this prevents cracked welding.


  • Plastic is a far less common boat trailer material.
  • It is highly resistant to corrosion.
  • Most plastic trailers are made with roto-moulded polyethylene.
  • It’s more typical for wheel arches to be made with plastic, than a whole boat trailer.

What size boat trailer is right for me?

The table below is a guide, which will help you understand what size of trailer will best suit your boat. Of course, each state has statutory requirements surrounding boat trailer sizes, so please check these before making any final decisions.


Boat Recommended Trailer
·        Aluminium boats; and

·        small lightweight fibreglass boats;

·        with Gross Trailer Mass (GTM) under 750kg.

·        Unbraked with a single-axle.


·        Alloy; and

·        fibreglass boats;

·        approximately 5.5m and with GTM under 2000kg.

·        Mechanical brakes with a single-axle.

·        Note: Trailers with a GTM of 1500kg+ are typically more suited to a tandem-axle trailer.

·        Alloy; and

·        fibreglass boats;

·        5.5m to 6.5m and with GTM under 2000kg.

·        Mechanical brakes with a tandem-axle.


·        Alloy; and

·        fibreglass boats;

·        6 to 8m with a GTM of 2000kg+.

·        Breakaway brakes with a tandem axle.

·        Braked on every wheel.


Boat trailer definitions

There are a number of terms you’re likely to hear when discussing boat trailers with sellers. Here are the most common ones:

  • Australian Design Rules (ADR) – regulate the compliance and construction of boat trailers in Australia.
  • Aggregate Trailer Mass (ATM) – the total weight of the boat (laden), motor and trailer when hitched.
  • Gross Trailer Mass (GTM) – the total weight of the boat (laden), motor and trailer when unhitched.
  • Gross Vehicle Mass (GVM) – the total weight of the boat (laden), motor and trailer.
  • Tare – the trailer’s total weight.
  • VIN – the Vehicle Identification Number (similar to a car).

Get your boat trailer insured

For competitive boat trailer insurance, please contact our marine underwriters. If you’d like more boating tips about equipment in and out of the water, please Like our Facebook page, or check back on our weekly blog.