16”x12” propeller on A25?

[tribologist]

Saw a used, like new 16x12 RH prop for sale. Driftless has a 16.75x12 but only rev to 2700. Engine is rated at 3200. 2.04:1 reduction. Its like new. Should i buy it and try or is it not much different. Spare maybe?

[Dieselram94]

If it’s cheap enough, you can always have a prop shop clip it or repitch it too.

[tribologist]

Yes, it was in the $100 something range. Looked new

[dkirsop]

I had my 16.5"x12" trimmed to 16"x12". Also had the shop cup the blades to improve efficiency. Have been very pleased with results. Speed increased about 0.5 kts and cruising RPM could be reduced by about 200rpm, fuel economy increased proportionately. There was also a sound reduction of about 1/2 db with the lower RPM.

[tribologist]

So i went and got the prop. It looks kind of sporty with swept blades….

[tribologist]

Here is my stock one. Its also a 16x12 but looks more ” classic”…. Tempted to swap…

[dkirsop]

Michigan Wheel is a quality prop manufacturer. You got a good deal!

[DCatSea]

For what it's worth, I just switched out the OEM 15x11 on our 27FC by way of an experiment. The objects were: 1) to see if I could get to normal cruising with fewer revs, thereby 2) reducing noise; also, 3) improve low-speed handling, especially when backing in.
Results:
1) Reached cruising (6.5 - 7kts) at 2400 rpm as opposed to 2800-2900) with better uptake. Vibration negligible, running temp 150-160), OP 55-60. Engine seems perfectly happy (famous last words??).
2) Noise level at cruise way better than before. Next stage is updated insulation and a Db reading or 2.
3) After the initial shock of having a responsive boat, this may signal a huge improvement. 2 good dockings with crosswind in the latest.

Still need to do a full, longer sea trial and flank speed run to see how engine and gearbox react, but so far so good.

[tribologist]

For what it's worth, I just switched out the OEM 15x11 on our 27FC by way of an experiment. The objects were: 1) to see if I could get to normal cruising with fewer revs, thereby 2) reducing noise; also, 3) improve low-speed handling, especially when backing in.
Results:
1) Reached cruising (6.5 - 7kts) at 2400 rpm as opposed to 2800-2900) with better uptake. Vibration negligible, running temp 150-160), OP 55-60. Engine seems perfectly happy (famous last words??).
2) Noise level at cruise way better than before. Next stage is updated insulation and a Db reading or 2.
3) After the initial shock of having a responsive boat, this may signal a huge improvement. 2 good dockings with crosswind in the latest.

Still need to do a full, longer sea trial and flank speed run to see how engine and gearbox react, but so far so good.

Interesting!

What did you replace with?

[DCatSea]

An unused Michigan Wheel 16x14 3-blade from Craigslist for $120.00.

Should have added that in addition to this I had the drive train rebuilt - new cutless bearing, stuffing block (old style) removed, cleaned up and repacked, Drive Saver (German) stripped, thoroughly rehabbed. Everything polished up and shiny.

Something had to work better after this

[tribologist]

Wow thats a substantially larger prop!

[ssrig]

For what it's worth, I just switched out the OEM 15x11 on our 27FC by way of an experiment. The objects were: 1) to see if I could get to normal cruising with fewer revs, thereby 2) reducing noise; also, 3) improve low-speed handling, especially when backing in.
Results:
1) Reached cruising (6.5 - 7kts) at 2400 rpm as opposed to 2800-2900) with better uptake. Vibration negligible, running temp 150-160), OP 55-60. Engine seems perfectly happy (famous last words??).
2) Noise level at cruise way better than before. Next stage is updated insulation and a Db reading or 2.
3) After the initial shock of having a responsive boat, this may signal a huge improvement. 2 good dockings with crosswind in the latest.

Still need to do a full, longer sea trial and flank speed run to see how engine and gearbox react, but so far so good.

Wow! 15"x11" is OEM for the FC 27? That seems so small! What is your gear ratio and motor size?
I am pretty sure that when Albin increased the engine size on the A25 Super Deluxe to a VP 36 hp they installed a 17"x 14" prop, might be totally wrong on that.....

[WillieC]

ssrig, you are correct on the A25 spec. (Ours is 17X13.)

[ssrig]

ssrig, you are correct on the A25 spec. (Ours is 17X13.)

I might have gotten the 17"x 14" from the boat I was looking at - Alanje? The gear ratio must be quite different for the 27, I did like the push at low rpm's on the Alanje when docking with the big prop.

[DCatSea]

Bog-standard 4D61 Lehman in VG condition (1704hrs). 2:1 Hurth tranny. Performance with the 15x11 was uninspiring, and basically I saw the 16x14 on CL for a VG price and thought WTH I'll give it a shot. So far I'm a happy camper.