PDQ OWNERS FORUM

Can anyone provide insight on what is the proper size and pitch for the two props on our PDQ 34 with 100 HP Yanmars? I'm not sure what we have now, but I do know we get 3525 max RPM on our Port engine and 3560 RPM on the Starboard. I know these numbers are nearly 300 RPM lower than the 3800 WOT rating listed in the Yanmar manual for these engines.

Our diesel mechanic suggested that we find out what the correct size and pitch should be for this boat. I've seen considerable chatter on this topic in this forum for PDQ's with 75 HP engines. Anyone have prop info for the 100 HP engines?

Do you have 3 blade for 4 blade props.

If 4 blade the prop size is 17 x 14 for the 4JH4-HTE engines.

I have moved up to the 110 HP engines, prop size is now 17 x 17.

Mark C.

i think henry clewes did a lot on this.

http://www.snodoglog.com/

I have 3-blade props.

Thanks, Duetto, for the reminder about Sno Dog's Performance study on PDQ 34's with 100HP Yanmars. I had found that last year and forgot about it. He says the original props are: 17" dia x 14" pitch x 3-bladed.

It looks like our boat has 3-blade 17" x 15 props. If the original props were 17 x 14, what might be the impact of these slightly different props on our boat? Could this account for the loss of 300 RPM off the rated max RPM?

If I recall the conversation with my mechanic correctly, each 1 inch pitch change of prop was around 150-200 rpm difference up or down. In your case the 1 inch additional pitch could account for a good portion of the 300.

Mark

Thanks, that's helpful.