I'm buying a new Flexofold for my 1983 O'Day 34 "Windwalker", but first, I need to know the gear reduction. It's not stamped on the Hurth transmission, and that's the problem. My boat has a Universal Diesel model 5424, so in 1983 they either used a Hurth HBW-10 with a 2.14 to 1 gear reduction and later they used a Hurth HBW-100 with a 1.86 to 1 gear reduction. Some manuals state that they used a HBW-50 with a gear reduction of 2:1. That translates into a 17x12 rh 2 blade propellor or a 15x12 rh, and at around a thousand dollars, I want to get it right, especially for the sake of performance. Any advice? Thanks.