Originally Posted by Erin
It's actually not that mad!
You need to be able to weigh the noseweight of the hitch on the scales then roll the boat back a short distance and re-weigh. Based on a bit of maths comparing the weights and distance you rolled the boat back by you can estimate the mass. I did this on my setup and came to 1700kg. I then went to a weighbridge and it measured 1610kg, so not too far off.
Indeed, although its probably more complex with a twin or triple axle trailer(?), and manhandling 4.5 tonnes back on the trailer might be fun especially if its not got rollers.
However it does provide a possibility without the need to transport it anywhere, which given the boat is 4.5 tonnes is not going to be cheap/legal*. *delete as applicable!