Getting my trailer setup checked

[Joséjones]

I’ve towed my boat and trailer a few times now and recently, I met a previous owner of my boat who told me that she was sitting all wrong on the trailer. The vessel is now sitting further forward and not as flat on the rollers which doesn’t look right and the boat has a lot more movement when we are on the road.

Are the places I could take my boat and trailer to that could help me set it up so everything sits right and is safe for me, the boat and other road users? There is a lot to learn about towing a largish rig and as many opinions as there are trailers. It would be great to be able to take it to a place that could properly check it over.

[zebedee]

You appear to be on the east side of Melbourne?

First of all, unless the winch post has been moved, the boat should end up the same distance up the trailer as it always has.

Is there any evidence that the winch post has been moved; marks in the galvanising of the drawbar, etc?
How is the drawbar weight; as a rough guide, the distance from axle to coupling is longer than axle to transom, so if you can't stand at the stern of the boat without the front lifting then the drawbar weight is significantly lighter than you are. For a boat the size of the Sabre, the coupling should stay firmly on the ground with one person at the transom, and even two unless you're heavyweights.

The keel of the hull (the centre of the bottom of the hull, NOT the ballasted drop/swing keel) of almost all trailer sailers is dead straight, so that the trailer rollers down the centre of the trailer are all in line too, ensuring the boat is properly supported even if it is too far forward or too far back. The side bunks or wobble rollers or other supports however are set to the correct height for a particular place under the hull. If the winch post has been moved then any side supports are likely to be wrong.

Is the boat centred properly (left/right) on the trailer? If it's not then it won't sit properly (unless it's a duck punt or a Castle, which both have rather flat bottoms...) For some boats, (eg: Castles) a certain amount of, ahh, technique is required to get them anywhere near centred on their trailer. Some others just stay centred with no drama.

Is the boat on a tandem axle trailer? (Probably yes) If so, is it a load sharing tandem or a slipper tandem?
A load sharing tandem has an intermediate lever about 6" to 8" long connecting the front of the rear spring to the rear of the front spring and supporting the trailer frame. A slipper tandem has two completely independant axles, with the tail of the front axle tucked under (strictly above) the front of the rear axle.

If you have slipper tandem suspension, it is important to get the tow ball height about right for the trailer. If it is too low then the front axle will take a greater fraction of the load, interfering with dynamic stability. To fix this you can either adjust the ball height or alter the spring mounting heights. Obviously the latter is harder once the trailer has been built, though we adjusted Ray's suspension when we rebuilt it, with good results.

[luke.sleeman]

Is is possible you can post some pictures? Perhaps people here can look it over and give you some more detailed suggestions?

Good on you for committing to making it right! Having your trailer setup properly makes a huge difference, both to your safety and how much effort and stress is involved in towing. Its something that's definitely worthwhile putting the time and effort into.