New propellor - Campbell Sailor

[Ron Hill]

Then you got your answer!!!   

A thought

[waughoo]

Pbyrne,

Out of curiosity, I looked up my CS dimensions.  It is a 13.750 x 7.  I am able to reach max RPM at full throttle (about 25 to 50 rpm shy) and cruise at 2400 to 2600 rpm at about 6.25kts and max at about 7.1 to 7.2kts at 3150 rpm.

[pbyrne]

Pbyrne,

Out of curiosity, I looked up my CS dimensions.  It is a 13.750 x 7.  I am able to reach max RPM at full throttle (about 25 to 50 rpm shy) and cruise at 2400 to 2600 rpm at about 6.25kts and max at about 7.1 to 7.2kts at 3150 rpm.

Interesting.  That means what they quoted is over pitched at 14x8...?

[pbyrne]

Then you got your answer!!!   

A thought

I thought so, but then the 14x7 comment came up! LOL

[waughoo]

I dont know that yours would be over pitched at the quoted spec.  I am experienci g some cavitation at full revs.  I suspect I am on the edge of being under pitched.  The mfg offers repitching service as part of purchase.  I wouldnt agonize over it.

[Robert Mann]

I have the Campbell Sailer RH14x8 fitted to mine, as recommended by West by North.  Beats the nasty Martec folder hands down.  Mainly as I can raise the idle to a sensible point and stop the vibration at low idle. Talk to West by North before ordering, get the straight scoop from them.  I think mine is slightly over propped as it won't get to 3000rpm.  However, that said, I think my diesel is 10 years old and that is probably contributing more to the lower performance of the engine than the prop. 

[pbyrne]

I have the Campbell Sailer RH14x8 fitted to mine, as recommended by West by North.  Beats the nasty Martec folder hands down.  Mainly as I can raise the idle to a sensible point and stop the vibration at low idle. Talk to West by North before ordering, get the straight scoop from them.  I think mine is slightly over propped as it won't get to 3000rpm.  However, that said, I think my diesel is 10 years old and that is probably contributing more to the lower performance of the engine than the prop. 

Yes, I'll call to put in the order.  How do you find the performance?  One thing I will say for the variprop is it never felt like it struggled to weather with chop.  Always plenty of power to punch through.

[Robert Mann]

To be quite honest, I barely motor so my comparison is a bit meaningless.  I will say the Martec was lousy going astern and the CS is a considerable improvement on that.  Theoretically you will lose some speed under sail as the prop just isn't as hydraulically efficient as a folded one, however I consider the improvement in idle setting, the less hammering on the shaft and skeg shift from forward to astern and the improvement getting out of the slip is worth the slight loss in sailing performance.

[Noah]

however I consider the improvement in idle setting, the less hammering on the shaft and skeg shift from forward to astern.

Not sure if those points are valid with all folding props? I have a 3-blade Flexofold" and have not experienced those "downsides"

[Robert Mann]

Noah, I don't disagree with you. The points are purely related to the prop the PO of my boat installed. The Martec I had was about the most basic of its kind.

[Robert Mann]

Pbyrne, one or two things to remember, if you are installing the prop. You will need to lap the prop taper to the shaft. Use fine valve grinding compound. Get a tube of Engineers Blue apply a very small amount to the shaft to check that the tapers are mating properly. When the tapers are close the prop will stick hard to the shaft and you might need a puller to separate them.  Do not let a boat yard beat your props off with a hammer. This can damage the transmission bearings, never mind other parts.  This is a common practice. My shaft is stainless, which replaced the standard bronze one, which the PO damaged when one wing of his folder stuck! The shaft was butchered to fit the Martec prop. This caused me to have to redrill the shaft to allow the cotter pin to be installed. Be prepared when you remove your prop in case similar issues have occurred.

[pbyrne]

Just so I have a refence point, the C34 MKII came with a 15x9? 

https://www.catalinadirect.com/shop-by-boat/other-catalinas/engine/props-etc/propeller-3-blade-15-x-9c-310-c-320-c-34-c-36/

[Robert Mann]

Pbyrne, that is the standard prop.  Don't try that diameter and pitch with the Campbell Sailor or you will overload the engine.  The shape of the CS blade makes a considerable difference and the 14x8 is the recommended size for Mk II with M35.

[pbyrne]

Pbyrne, that is the standard prop.  Don't try that diameter and pitch with the Campbell Sailor or you will overload the engine.  The shape of the CS blade makes a considerable difference and the 14x8 is the recommended size for Mk II with M35.

Yes, just trying to confirm the standard out of the box prop for reference.

[High Current]

Yes, just trying to confirm the standard out of the box prop for reference.

Confirmed, as far as I know.  My 1990 Mk 1.5 has a 15x9 2-blade.

I'm glad someone explained the CS blade shape; I was very confused why everyone was talking about smaller+shallower props on an M35B than I have on my M25XP!  Although I wouldn't have expected shape to have THAT much impact.  Gearing is also a factor (1.79:1 vs 2.05:1), but the M35 should still have more torque at max speed.