Good morning Barry & Robyn,
the ratio between your VOLVO/PERKINS TMD22 and the C-drive is 2.74/1. The C-drive is 1/1.
Your Yanmar supplier may suggest that you install a ZF 30M mechanic gear-box with a 2.69/1 ratio. However, your current HURTH-ZF HBW-250 could be re-installed as long as it is in good condition (it can be re-built with a new discs kit).
On Thursday, February 4, 2016 3:11 AM, "seagasm@... [amelyachtowners]"
Can someone tell me the ratio between the Perkins TMD22A and the C drive unit. What changes have been made by those who successfully have replaced the Perkins with a Yamnar engine?
Barry & Robyn
Tradewinds III SM # 171