Boat trailers guide
Towing your boat is not fun, no matter how many times you do it. You’ve checked your mirrors for the umpteenth time. Your clammy palms grip the wheel tighter than a boa constrictor’s embrace. You try to maintain a calm smile, but the sweat beading on your brow threatens to give you away and your sphincter’s puckered up like it’s sucking on a lemon. Your senses have become more acute over the last 20 minutes, too. Was that a clunk? Is that a vibration? Paranoia jumps into the seat next to you and jabs you in the ribs. Your eyes continue to dart up and down — mirror, road, mirror, road.
Something’s following you, tracing your every move. This tailgater’s had his nose up your tailpipe ever since you left home. Not long to go now. Soon it will all be over. You drive into the dimly-lit car park. You stop, engage the handbrake and breathe a huge sigh of relief. You’ve survived another one. You open the door and exit, noting the tailgater is still there lurking, taunting, mocking…
In my alter-ego as a mild mannered boat salesman, I get to witness the boat selection process first-hand on a daily basis. Almost without exception, trailers tend to be one of the last things I get quizzed about. So either boat buyers are a pretty trusting bunch — hard to imagine on account of the grilling I get over the rest of the boat — or maybe they just don’t care, ’cos it’s hidden under all that new shiny fibreglass or freshly baked paint. Seriously, more focus is often placed on the location of one of 20,000 rodholders they want fitted than the very contraption that keeps them off the bitumen.
Finding the best boat trailer
So what does a good boat trailer look like? Is price and brand name a fair consideration? Is local best or will a cheaper, imported one do? We’ve taken a poll and tallied the votes and you’ll come out the winner. But before handing over the credit card, it’s important that you establish whether the trailer you have your eye on is really the right one for you. This is critical and crucial to both your sanity and your hull’s longevity. If you’re a new boat buyer, odds are the dealer’s done all the hard work for you and shoehorned an appropriate one under your dream machine. If not, dear friends, read on…
Boat trailer rollers vs skid trailers
Depending on the hull, the trailer would generally fit into one of two broad categories: multi-roller or skid. Multi-roller trailers, with or without the addition of a “ladder” of keel boat trailer rollers, are well suited to fibreglass and plate-alloy hulls and are the most receptive to having a boat driven onto them. Many have flexible rear cradles which “receive” the bow and align the hull as it drives up the trailer. They are pretty forgiving and reliable in most conditions.
Skid trailers, on the other hand, are the ideal choice for pressed-alloy and roto-moulded plastic hulls, where the poly, Teflon or carpeted timber skids suspend the generally lighter hulls over a greater surface area, thereby resisting hull flex when trailered. In my experience, they are generally not as easy to drive on as multi-roller trailers but that can change with a bit of practice. Exceptions to this rule are fibreglass ski and wakeboats along with the shallower, American-style bowriders, which typically run on carpeted skid trailers. Multi-hulls such as cats and tri-hulls along with pontoon boats can utilise variations of either, subject to the manufacturer’s recommendations.
Definition of boat trailer terms
When confirming your trailer’s suitability or when registering or insuring it, you will be confronted with a bunch of acronyms you’ll need to get your head around. Here are the most commonly used ones below:
VIN: Vehicle Identification Number.
GVM: Gross Vehicular Mass — the combined laden boat, motor and trailer weight.
GTM: Gross Trailer Mass — the combined laden boat, motor and trailer weight (unhitched).
ATM: Aggregate Trailer Mass — the combined laden boat, motor and trailer weight (hitched).
TARE: The total weight of the trailer itself.
ADR: Australian Design Rules — which govern the construction and compliance of your trailer.
Steel or aluminium boat trailers (or plastic)?
Modern boat trailers are generally constructed of steel (galvanised or not), aluminium and, to a lesser degree, plastic (generally of the roto-moulded variety). Here are the main points to bear in mind of each…
Steel boat trailers
These are by far the most common and should ideally be galvanised if used in salt or brackish water. Steel trailers can be readily painted to satisfy the fashion conscious, but keep a tub of touch-up handy just in case. Easytow’s Mick Whitehead was also keen to point out that in a similar manner to a painted aluminium hull, paint also creates another barrier against the elements — when paint over gal is specified, it could potentially double the service life of a trailer. Steel is a durable option, but treat your trailer to a shower after dunking it in the salt.
Aluminium boat trailers
These are light in weight and durable — to a point. They’re not prone to rusting but inferior-grade alloy and substandard welds are things to watch out for, as they can turn your investment into a Meccano set. Keep an eye on cracked welds due to constant flexing. Some manufacturers, such as alloy juggernaut Telwater, choose to bolt the entire trailer together as a way of alleviating this. Other manufacturers, such as Dunbier, and Mackay, use a proprietary extrusion that is intended to flex in the beam and not at the welded joints.
Plastic boat trailers
Yes, they’re a thing, notably roto-moulded polyethylene trailers. They’re a rarity but their construction material makes them the most corrosion-resistant option. Some are even filled with water to add weight and to better place the rig on the road. Generally though, plastic is more commonly used for the wheel arches on metal trailers; they’re not a common sight in their own right.
Custom trailers
It’s important to remember that while standard-issue trailers are probably perfect for about 90 per cent of boating applications, even the “ideal” boat trailer can be improved upon if your intended use is outside the box. For instance, if regular long hauls are on the cards, you may be better served by a tandem trailer, even under a smaller hull. Custom trailers (or ‘customising’ an element of your trailer) can help here.
Having a spare axle and a couple of extra boat trailer wheels is good insurance in the event of a puncture or blowout. Same deal if you’re going to be tackling rough terrain and rutted roads such as those commonly encountered in the outback, or local bush tracks. In this scenario, upgrading your suspension and maybe replacing the standard tyres with off-road ones are also valid considerations. Boat trailer brakes are another issue demanding your attention and are governed by strictly-enforced State legislation.
What size trailer do I need for my boat?
The following guidelines to boat trailer towing and load weights should serve as a guide, but be sure to check the statutory requirements with your local authorities.
Boat weight and length | Best trailer |
Aluminium boats and small lightweight fibreglass boats with a GTM (Gross Trailer Mass) below 750kg | Unbraked single-axle trailer. |
Alloy and fibreglass boats to around 5.5m and with a GTM below 2000kg | mechanical brakes, single-axle trailer. (NB: Rigs with a GTM over 1500kg are generally better served by a tandem-axle trailer.) |
Alloy and fibreglass boats 5.5m to 6.5m and with a GTM below 2000kg | Mechanical brakes, tandem-axle trailer. |
Alloy and fibreglass boats 6.0m to 8.0m and with a GTM 2000kg and above | Break-away brakes, tandem axle, braked on all four wheels. |
Triple-axle trailers | Breakaway brakes, braked on wheels. |
Imported boat trailers?
Now I wasn’t going to be drawn into the imported versus local debate but I just can’t help myself. The recent influx of imported American boats, particularly private or grey imports, has not gone unnoticed by the local revenue raising authorities and an inside source warns that ignorance is no longer an accepted defence.
It’s common knowledge that a high proportion of these imports over 6m in length are nudging a portly 2.59m in girth — 9cm over our national unrestricted towing limit. If you get caught, you will get pinged. So learn the rules — they vary from State to State just to keep things interesting — and make appropriate use of the “wide load” signs.
Where the waters get really muddy though is when private imports are involved. I’ve attempted to wade through the legislation and almost drowned under the scope of it, so I swam to the shallow end and decided instead to stay in the kiddies’ pool.
Before you head off
Before you drive off, check and re-check that your trailer is properly secured. I normally start at the front and do a 360 around the rig. My checklist reads as follows:
1. Boat trailer winched snug.
2. Ratchet and pawl (the little dog leg thingy with a spring on it) engaged.
3. Safety chain on.
4. Coupling-hitch down and clipped on (pop a clip on it to be doubly safe).
5. Handbrake off.
6. Safety chains shackled on.
7. Trailer plug in.
8. Jockey wheel up.
9. Spare boat trailer wheel firm.
10. Check wheels and bearing protectors (bearing protectors have a nasty habit of going AWOL).
11. Tie down straps tight.
12. Bungs in (yep, before you leave your driveway — trust me on this one).
13. Check lights.
14. If your trailer has electric brakes, you also need to ensure that your brake actuator is priming and functioning properly.
So there you have it. Everything you need to know about trailers.
Originally published in TrailerBoat #279, March 2012.