Albin 27 driveline variations

[motthediesel]

I don't know how many of you have seen this thread in the "Maintenance" section:

http://www.albinowners.net/aog/viewtopi ... =7&t=12146

I am trying to reduce the driveline vibrations in our '85 27FC. Our boat has the Lehman/Peugeot engine, a 1-1/4" shaft, and no intermediate bearing between the stuffing box and the transmission.

I would like to take an informal poll of the A27 owners here to see:

What engine your boat has?

What diameter shaft is it equipped with?

Does it have an intermediate shaft bearing?

How would you rate (unscientific, I know) your driveline smoothness?

I.E:
1 -- Smooth as silk,.
2 -- Noticeable, but not obtrusive.
3 -- Like a washing machine with a bowling ball in it.

To start, I would say ours is somewhere between 2 and 3

I also understand that some of you may well have the shaft bearing without knowing about it. In the FC boats the shaft runs under the fuel tank and it's difficult to even see under there. I don't know about the sport models, but I'm guessing the water tank might be there?

Thanks in advance for the help!

Tom

[tego]

"87 27FC, hull #302, with LD28 Nissan, 1 1/2" shaft with NO intermediate bearing and no vibration at either low or high speed, running a 18"x14" 4-blade prop (LH). Ben

[motthediesel]

"87 27FC, hull #302, with LD28 Nissan, 1 1/2" shaft with NO intermediate bearing and no vibration at either low or high speed, running a 18"x14" 4-blade prop (LH). Ben

Thanks -- you've got a big prop too, we turn a 19/12 on ours. That extra .25" shaft dia could be a factor in your favor.

[DesertAlbin736]

Caveat: La Dolce Vita is an A25, so somewhat apples vs oranges compared with A27.

That said, as noted in my signature, our engine is a 24 HP Yanmar 3GM30F. It runs fairly quiet with minimal vibration. I attribute that partly to the Yanmar being a more modern quieter engine vis a vis the stock Volvos as well as being a much smaller engine than those in Albin 27s. Also as inherited from previous owner's repower job, it's equipped with an AquaDrive CV joint/thrust bearing unit. That I believe makes a difference in vibrations, as it allows use of soft engine mounts & deals with any minor misalignments. I can tell you the time we got a ride on Stephen D's (aka sunsetrider) Volvo MD17C equipped A25 over in Gananoque we were shocked by the difference in noise & vibration. If we do manage to stop by & visit this summer would be glad to take you out for a short spin in our boat & show what our installation looks & sounds like.

[Ambler27FC]

80hp Perkins, 1.5” shaft, no intermediate support bearing, 18” prop. I have noticed no vibration noise above the noise of the engine - but it is something I will be looking at after a re-engine. Would have to pull out a book, but I believe the stiffness of a beam increases by a power of 4 with diameter, so small changes in diameter can be significant. I would think the intermediate bearing would require better alignment and would have higher resonant frequencies.

[motthediesel]

Yes, the extra quarter inch could make a significant difference in stiffness. With close to 6 feet of unsupported shaft, it’s very possible that my 1-1/4” shaft is getting slightly out of column under load. After all, the entire thrust of the propeller is being sent through that rod to the gearbox.

[motthediesel]

Just to give it a little more thought — a rough estimate is that one horsepower equals 25 pounds of thrust. So even at cruising power of say 30 hp, that’s 750# thrust on the shaft, or 1500# at full power. Would you want to support 750# on a single 1-1/4” bronze rod 6’ high? I sure wouldn’t.

I think that the builders at Albin first added an intermediate bearing, and then went to a larger shaft, might indicate that they knew the original equipment was lacking.

[Ambler27FC]

I’m wondering if they increased the diameter to eliminate the middle bearing , or if it was due to the trend towards higher HP motors. Mine is an ‘87. Pure speculation here.

Hope it is just the mounts and not the shaft if you have a serious concern.

[coolchange]

89 with 1.5 in. shaft and no carrier runs off a 157hp Isuzu with no vibration...just a little engine noise at higher rpm. (not sure of prop)

[SkipD]

85 FC
Beta Marine 50
1.25” shaft
Intermediate bearing
18x13 RH prop
Also have a Python Drive CV joint

Would say that there is minimal to no vibration related to the shaft. I have been focusing on vibration-noise originating in prop clearance. New cutless bearing installed with engine and PythonDrive in 2018. Also replaced intermediate bearing as the fuel tank was out. New shaft too.
Not much more could have been replaced.......

Ve

[motthediesel]

Well, that’s interesting, that is the first small shaft/carrier bearing setup reported here.

I too worry about the tip clearance, as we have an even larger 19” prop on ours. The saving grace in that regard is that (as I understand it) tip clearance noise is more of a problem at higher propeller rpms. We seldom exceed 1800 rpm, and with the gearbox reduction, that’s a pretty slow turning prop.

That Beta 50 is supposed to be a nice engine, if we ever replace “Pepe le Peug” we’ll take a hard look at one of those. Are you happy with it?

Tom

[davem554]

"87 27FC, hull #302, with LD28 Nissan, 1 1/2" shaft with NO intermediate bearing and no vibration at either low or high speed, running a 18"x14" 4-blade prop (LH). Ben

t
Ben, Just curious, I have the same boat as you with 18x14 3 blade prop. How does your boat
Speed, power , backing up, etc.
Dave
Thanks Ben

[DCatSea]

May be looking to replace our old prop, which I believe is an 15x11, but have possibly related question:

To cup or not to cup, and if so, to what degree? Anyone had any experience with this?

I refer to this Prop 101 text: https://bblades.com/props-101/

Thanks.

[tego]

Dave, I'll get back to you tomorrow- I'll get my log book and give you RPM vs speed. I know that a 4-blade has more bite at the lower speeds I usually operate at, and is quieter. It is very efficient in reverse and "prop-walk" of a 4-blade is more pronounced and I like that when maneuvering in the marina. Ben

[dkirsop]

My boat is an A25. When recently having my prop tuned I decreased the diameter by 1/2" and had the blades cupped. There was a measurable benefit in that my fuel economy increased by about .1L/h at standard cruising speed and RPM. Physically you are unlikely to notice the difference but it is nice to know that the engine is working a little less hard.