[Knot On Call]

I'm looking to change my 3 blade props to 4 blade to eliminate some vibration on my 2004 Sovran Salon with 3406e Cats. My engines are aligned, shafts dialed in, and props reconditioned and balanced. Any comments welcome.
I'm looking for a set 4 bladed 2.75 in shaft, 31 x 39.

[jclark003]

I have a set of Veem interceptor 4 blades on my 52. Don’t have the size handy but probably close to what you have listed. I can check if you are interested. Vibration is almost non existent and after tuning, the prop demand / fuel burn numbers stay below Cats recommendation between 1600 and 2000 RPM where after it tracks pretty close to spec. WOT sees about 20 rpm over rated engine speed. I couldn’t be happier. Between 1750-1850 I am getting about .58 a .6 mpg in fresh water depending on weight and sea state.

[Knot On Call]

I have a set of Veem interceptor 4 blades on my 52. Don’t have the size handy but probably close to what you have listed. I can check if you are interested. Vibration is almost non existent and after tuning,  the prop demand / fuel burn numbers stay below Cats recommendation between 1600 and 2000 RPM where after it tracks pretty close to spec. WOT sees about 20 rpm over rated engine speed.  I couldn’t be happier. Between 1750-1850 I am getting about .58 a .6 mpg in fresh water depending on weight and sea state.

[Knot On Call]

Thanks for the info. I would like to know more about what you're running. I currently run at 1930 rpm sweet spot getting .48 mpg. My WOT currently is 2525-2530 rpm. I tend to run a little heavy with 1/2 full fuel (350 gals) and 100 gal water. I have had reports that people still get some vibration in our model with 4 blade and even 5 blade props.

[jclark003]

Maybe you mean 2325 on the WOT? +2500 would really be spinning those engines.

The 52 has very long shafts and tend to get shaft whip in certain conditions and certain rpm ranges. For the most part I get almost no vibrations once I get over 1600. Below that and the hull gets inefficient causing the engines to work hard and put a load on the shafts. Thats pretty much the only time I get shaft whip/vibrations.

I am running 32X38 with the lightest trim strips on the props. WOT is 2320 at near full fuel load. I cruise around 1800 and at half fuel I usually see about 27 mph @48 GPH ( about .56 MPG). I want to say at 1900 I am around 29 MPH and about .52 MPG. Backing down to 1700 gets me to about .58-.6 MPG but the boat starts to feel heavy. I run in fresh water so I suspect I would pick up performance in salt water.


I very much like that the engine loading/ fuel burn numbers are below what Cat recommends until about 2000 and above.

Hope this helps.

[Knot On Call]

You are correct I meant my WOT to be 2325-2350 RPM. You have great efficiency numbers and higher speed at lower RPMs. Thanks for your help. I'll look into the Veem blades. Could you please explain what are the trim strips that you mentioned? Mike

[jclark003]

Veem interceptor props have removable strips that allow the owner to fine tune the wheels. Apparently this can be done while in the water though I’ve never tried it. They have 4 or 5 different colored strips that increasingly increase pitch depending on the color. I run the white strips which offer the smallest change.

[Knot On Call]

Thank you.