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RTIME · Joined: 29 Jul 2007 Posts: 15 Location: Pasadena, Maryland

Hi all
I have a 43' Endeavour Ketch; with a Yanmar 62.

I am not able to reach the RPMs that supposedly I should with the Yanmar 62 Diesel Engine.

One issue may be a prop of incorrect size and pitch - The prop now is 20RH12.

My question to all other 42 and 43 Endeavours - especially anyone with a Yanmar 62 is - What size and pitch prop are you running?

I've already spoke to a number of vendors and no one has same advice as to size and pitch - "try it and see" not all that reasonable as I see it to do.

Thanks for any info, thoughts, advice

Bob
R'Time
ohstrebor@earthlink.net

ssteakley · Joined: 28 Jul 2007 Posts: 26 Location: Austin, TX

Bob,
I have a E42 with a 66hp Yanmar. When we bought the boat it was a similiar situation. The boat surveyor told us to have the turbo charger cleaned or repaired. Shortly after buying the boat we had it hauled for some repairs & I had the Prop balanced and pitched. (The turbo charger checked out and was working properly). After returning to the water we had no problem reaching hull speed. Later I found out the previous owner had it over-propped on purpose. It was his opinion it helped motoring in heavier seas. The boat performs just great for us and the fuel effiency is better.
_________________
Steve & Lynn Steakley
87' E42 "Wand'rin Star" #205
Corpus Christi, TX

JMadden · Joined: 06 Aug 2007 Posts: 7 Location: Kirkland, WA

Bob,
Two seasons ago I resized my prop because I was experiencing too much smoke and not reaching top RPM. Dave Gerr's "Propeller handbook " does an excellent job of discussing all aspects of prop performance sizing and selection. Good book to read for a complete understanding. Still you can distill it down to a few simple variables and a formula. Reading the book will arm you with the knowlege of what is fluff and what is right info.

There are several variables that direct the prop selection process. What is key is knowing the actual numbers for your boat. Things like actual displacement vs. designed displacement, shaft HP vs. engine HP, and actual LWL.

Case in point on my E35 the disp. is 13000# +-, but the actual hauled weight is 22000#. A difference that influences LWL and determined the size of the engine that it will take to push the boat to hull speed.

From "The Propellor Handbook" there are formulas and charts that give performance based on these factors to come up with a prop selection.

I've experienced a HUGE difference in performance and handling of the boat. I was fortunate that I could reuse my old prop and get it repitched.
Before;
max RPM under load: 2600rpm (smoking like mad, an overloaded condition)
max RPM no load: 3300RPM
Cruise spd: 5.8 kts @ 2200rpm

After: (also calibrated my tach)
max RPM under load: 3000rpm
max RPM no load: 3600
Cruise spd is abtainable with less effort of the engine and I can go to 3000rpm and get the full output of the engine and get 7.5 kts and above.

Slow speed manuvering has improved. We don't start moving when we put it into gear, but rather by increasing thottle. The repitched prop has less wash and makes backing easier.
_________________
Jim
Blessing; E-35 #115; Kirkland, WA

endvr32 · Posted: Mon Oct 19, 2009 8:50 am Post subject:

If you CAN'T reach max RPMs on your engine (or you can reach hull speed below max RPMs), your prop is TOO LARGE

If you CAN reach max RPMs but not hull speed, your prop is TOO SMALL

Generally the prop needs to have a minimal distance between the blade and the hull. There's a formula for determining the clearance of the blade tip to the hull. From there it's all about pitch.

_________________
Paul Uhl
Endeavour Owners Forum
www.endeavourowners.com