How to Choose the Right Boat Trailer
Selecting the right boat trailer is just as important as choosing the boat itself. A well-matched trailer ensures safe, hassle-free transport and protects your investment, making every trip to the water easier and more enjoyable. At Chivers Marine, we understand how crucial it is to find the perfect fit, that’s why we offer a detailed boat sizing guide to help you make the best decision. In this guide, we’ll take you through the key factors to consider when selecting a trailer.
Types of Boat Trailers: Bunks vs. Rollers
The two main types of boat trailers are bunk trailers and roller trailers. Bunk trailers use carpeted wooden boards to support the hull and are great for deeper, developed boat ramps. They’re typically more affordable and better suited for lightweight boats and smooth launches.
Roller trailers, on the other hand, use wheels to help the boat glide on and off with minimal effort. They’re ideal for shallow or uneven ramps and provide more versatility for those exploring remote or undeveloped waterways. Your choice depends on where you’ll be boating and the kind of access you need.
Trailer Sizing and Weight Distribution
Trailer sizing starts with measuring from the bow eye to the transom, and includes the beam, deadrise angle, and hull features such as strakes or steps. Proper sizing ensures safe towing and good handling. Ideally, about 7–15% of the total weight should rest on the tow ball. Too little downforce can cause sway or even lead to dangerous jackknifing.
It’s important not to exceed the ball weight limit set by your vehicle manufacturer, so be sure to check your towing specs before finalising your trailer choice.
Boat Type and Hull Design Considerations
Different hull shapes require different support systems. For example, V-shaped hulls generally work better with bunk trailers, while flat-bottom boats may benefit more from roller trailers. The material of your boat: fibreglass, aluminium, or composite, also plays a role. Some materials need additional protection during transport, which your trailer must provide.
Brakes and Suspension: What You Need to Know
Even today, many trailers still use leaf spring suspension a reliable and low-cost option. However, torsion bar systems provide a smoother ride and are favoured by some manufacturers for their performance.
Braking requirements depend on trailer weight:
- Over 750kg GTM: Brakes are legally required.
- 750kg–2000kg ATM: Must have mechanical, hydraulic or electric brakes on one axle.
- Over 2000kg ATM: Must include a breakaway system that activates brakes if the trailer becomes disconnected and keeps them engaged for at least 15 minutes.
- All brakes must be controllable from the driver’s position.
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Calculating Trailer Load Capacity
To calculate the proper load capacity, add the combined weight of:
- The boat hull
- Engine
- Fuel (multiply litres by 0.8)
- Water (1 litre = 1 kg)
- Batteries, gear, and other accessories
- Then add a 15% safety margin for good measure.
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Trailer compliance plates help decode trailer capacity:
- Tare: Trailer weight, empty
- GTM: Max weight on wheels while hitched
- ATM: Total weight when fully loaded
- GCM: Combined max weight of trailer, vehicle, passengers, and cargo
Need help finding the right boat trailer? Visit Chivers Marine. We’re here to make sure your boat trailer is the perfect match for your next adventure.
