Save your money and buy a good used or new Aluminum framed trailer. You are just pissin into the wind trying to save that relic if you have to weld on it.What are the springs ,axles , wheels, , tires and bunk brackets like ?
If they are shot best to invest in a new torsion axle aluminum trailer. springs are a lost cause in saltwater ,if you use your boat regularly you will be replacing them every year otherwise.
My 02.