You should be OK, but I'd check.
I have an Avon 4M with console steering A frame etc, and this weighs inc engine (40hp 4 stroke) at just on 330Kg
Add battery (25Kg), 25L fuel tank fuel (25g), Bow ballast (30Kg) Anchor & chain (30kg)
the total weight is 440Kg for my all up weight
You should be able to calculate the weight of hull / engine & key components. if in doubt take it to the nearest public weighbridge. You will be legal if you are intending to check weigh.
If you are marginal, consider what kit you could carry inthe vehicle, not on the trailer (e.g fuel tank, anchor etc