Engine performance

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   What is your cruising RPM and speed in calm/no tide conditions?  Also what is your max RPM?  And if you know, what size and pitch of prop do you have?

We have the Volvo D2 75 on our 505.   I suspect she is rather over propped as we can only get to 2,400 RPM on full throttle (should be able to get to 3,000).   We cruise at 7kn (just) at 1,900 RPM.   Any higher revs get us going a bit faster but the engine seems very strained - probably due to the over propping.   This is a Flexofold 20" diameter 14" pitch 3 blade.

Would be grateful to confirm this by comparing to other owners, please.

PS I know this depends on type of prop too, however I think prop size and pitch is just as important as prop type - if not more so.  Nigel Calder's testing and writing is pretty good on that. https://www.mysailing.com.au/gear/folding-prop-gear-test

Edited by colinc - 09 November 2019 at 12:10

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colinc Members Profile Send Private Message Find Members Posts Add to Buddy List Lieutenant Joined: 08 May 2019 Location: UK Status: Offline Points: 48	Post Options Post Reply Quote colinc Report Post Thanks(0) Quote Reply Topic: Engine performance Posted: 09 November 2019 at 10:03
	What is your cruising RPM and speed in calm/no tide conditions? Also what is your max RPM? And if you know, what size and pitch of prop do you have? We have the Volvo D2 75 on our 505. I suspect she is rather over propped as we can only get to 2,400 RPM on full throttle (should be able to get to 3,000). We cruise at 7kn (just) at 1,900 RPM. Any higher revs get us going a bit faster but the engine seems very strained - probably due to the over propping. This is a Flexofold 20" diameter 14" pitch 3 blade. Would be grateful to confirm this by comparing to other owners, please. PS I know this depends on type of prop too, however I think prop size and pitch is just as important as prop type - if not more so. Nigel Calder's testing and writing is pretty good on that. https://www.mysailing.com.au/gear/folding-prop-gear-test Edited by colinc - 09 November 2019 at 12:10

kipwrite Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 14 October 2015 Location: New York Status: Online Points: 165	Post Options Post Reply Quote kipwrite Report Post Thanks(0) Quote Reply Posted: 09 November 2019 at 14:34
	We have a d2-75F engine with the flex o fold 3 blade prop. Not sure of diameter and pitch. With the bottom clean, RPMs max out around 2750, and she will do 7.5 kts at 2000 rpms. If I run the RPMs up, she will get to 8+ kts. We generally cruise between 1800-2100 RPMs, the lower side giving us much greater range on passages, while still maintaining 7kts (if things are settled).
	Kipwrite



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