3 Blade Prop for Cruising

[Kurt]

Question for ya all. I have a 1976 C&C 33' with a V-drive and an original 2 blade prop. I get confused on this 2:1 reduction gear stuff. I was told that some V-drives are 1:1, but I thought they were all 2:1 - guess I don't know what that means. Anyway, when I do my open ocean cruise (well I only end up about 50 miles offshore) up to Catalina Island every summer, I'm finding that with rough seas and a nice headwind I can only make about 4.5 to 5.0 knots at 1800 rpm. This is a 9,600 pound boat. The trip takes me 2 to 5 hours longer to make in this boat than my old Ericson 27' with a 15HP outboard. So, I was wondering if it is a decent idea to have a spare 3 blade prop to use just for cruising. My motor performs fine in the bay, but just doesn't seem to move enough water in a good swell with good wind on the bow. So, does anyone change out to a 3 blade for cruising and, if so, what is a good 3 blade prop for the A-4 on this type of boat? I think the Indigo is just for direct drive, correct?

Any wisdom appreciated - I would like to cut the 15-18 hour trip back down to my old 12-15 hours.

[msauntry]

See if you can get your current prop repitched a little lower to give you more rpms and power. Sounds like your overpropped a bit.

[tenders]

If you have three holes in the coupling between the transmission and the shaft, you have 1:1 reduction.

If you have four holes in the coupling, you have 2:1 reduction.

[sastanley]

Kurt,

Here are the different types I found at the C&C website with regards to A-4s. It appears that there are 4 possible ratios for V-Drives. I do not know how to figure out which ratio you have.

1.00:1
1.29:1
1.67:1
2.0:1

My understanding is that 2:1 means the output (prop) shaft spins at half the speed of the engine. Those of us with direct drive engines are often over-propped because the prop is spinning the same RPM as the engine, so we need to reduce our pitch (& often diameter as well) as compared to the majority of other marine propulsion systems.

These are the 'codes' for the engines:
5101 / UJ - base configuration Atomic Four

5111 / UJS - Stevedore configuration for Canadian market, power limited to 15 hp with intake manifold restriction)

5102 / UJR - reduction gearbox mounted on transmission, 2.04 ratio standard

5112 / UJSR - Stevedore configuration with reduction gearbox mounted on transmission, 2.04 ratio standard

5103 / UJVD - 20° angle Walter V drive gearbox mounted on transmission, 4 gear ratio options including 1:1

5113 / UJSVD - Stevedore configuration with 20° angle Walter V drive gearbox mounted on transmission, 4 gear ratio options including 1:1

[Kurt]

Thanks for the info, guys. I'll look into this further. Just think I can do better with a "cruising prop" with 3 blades to move more water at any given rpm. Maybe that's not possible, but I want to look into it. I do have a Stevedore with the Walter V drive, just not sure of the ration.

[sastanley]

kurt,
I was down at my boat this weekend, and my "UJ" engine code is stamped in the block just in front of the reversing gear. I do not have a v-drive so this is just under the coil on my motor, which is aft of cyl #4, opposite end of the motor from the flywheel.

Your motor may be backwards (reversed) from mine???
Here is a pic of my motor in the Catalina 30 - hopefully my white colored photoshopping to the pic makes things clear regarding orientation..notice the circled area which shows the engine code. Ignore the dirt & clutter!!