The PO of my boat had a 14' Novurania GRP hulled RIB, with Yamaha 50. I think it was about 800#. His davit was 120VAC, which lifted fine but was manual (uncontrolled) rotation. That led to some 'interesting' and at times dangerous wild swings of the RIB.
I could not change his old winch to 230VAC /50Hz. So now I use a Nick Jackson davit rated at 1500#. It has a 12V winch with hydraulic rotation and hydraulic ram lift on the boom also. My current tender is a 14' AB RIB, with aluminium hull and a Honda 40. It weighs a bit less the the old rig. The RIB fits fine on my 50' boat, and the weight is not a problem at all on the 'boat deck' above the salon. With hydraulic rotation it is a safe and easy one person job to launch and retrieve the RIB.