I will be able to put my boat in a garage this winter but will need to put a hinge on the trailer. Is there a particular hinge design that's best? Would it be best to have this done by a welder? If so, does anyone know a good place on the south shore?

Drinkwater Trailer on RT 53 in Pembroke
or
Monahans in Weymouth has trailer supplies and if they can't do it, I'm sure they'll know where to point you.

I will be able to put my boat in a garage this winter but will need to put a hinge on the trailer. Is there a particular hinge design that's best? Would it be best to have this done by a welder? If so, does anyone know a good place on the south shore?

What exactly are you trying to hinge?

just take the center tounge piece off for the winter.