Julian Porter wrote:The axle of my South African trailer is approximately half way along the length of the boat. I’ve seen a twin axle trailer where both axles are within the last 1/3 of the trailer (pretty much filling that section of the trailer. How can I determine if the weight on the hitch will be too great?
The sort of trailer you are describing is typically used with powerboats with a couple of huge outboard motors sitting on the transom. In other words the centre of gravity of the boat is well aft, hence the position of the wheels on the trailer.
I suggest you measure the actual nose-weight of your existing trailer with the boat loaded as it will be for trailing on the road. Ideally it should be approx 7% of the total towed weight (trailer + boat) for stability. However, you cannot exceed the maximum allowed for either the coupling on the trailer (typically 100 Kg) or the towball on the car, this can range from typically 70 Kg for a saloon to 250 Kg for some large 4x4s.
If the result is reasonable, you should aim for the two axles of the new trailer to be positioned equally either side of the position of the axle on your existing trailer. Assuming that the distance from the coupling to the axle(s) is the same.
If the result is too light or too heavy you can calculate using simple maths (moments) where the axle(s) should be, to give your desired noseweight.