The two and three bladed folding propellers fitted to Maxi Yachts currently use anodes bolted to the propeller for galvanic protection. Older propellers do not have these anodes and rely on the leg anode for protection. The propeller fitted with anodes is electrically isolated from the propeller shaft, the propeller without anodes is not. Apparently, some rope cutter installations can bridge the electrical insulation between the shaft and the propeller.
We are told that Volvo do not agree to rope cutters being fitted to their props and if you have a new propeller this invalidates the Volvo 3 year warranty. Volvo have stated that all their dealers are instructed to inform owners of this fact.
Hence owners who are contemplating a cutter should discuss it fully with an authorised Volvo dealer who should also undertake the fitting and provide confirmation of warranty.
Note: Saildrives are also electrically isolated from the engine block, at least on later models. Hence it is important to check there is no continuity between the leg and the engine. Do make sure the throttle/forward/reverse controls do not inadvertently short circuit the insulation!