Keith: I have an OA launched 1985...3 wipers, one per fwd window all were separate motors and all were inoperative when I bought the boat. I pulled them out when I did a 12month re-fit in 2009. Bought a single motor and a parallax arm with washer fittings plus control box from IMTRA, intending to reinstate over centre window only....am yet to get around to fitting it (not an easy job on my OA at any rate). Key to success is getting the shaft length right. If yours are still installed with intact shafts (mine had been cut off and a disc placed over) you should be able to measure the shaft length , which will make ordering easy. I also recommend the IMTRA folks: website is excellent and has a wiper blade calculator. They will also run the calcs for you if you send them window dimensions.