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Just got through having a mechanic attempt to re-align the shaft. He believes the shaft is bent as the gap moves with the shaft as he rotates it. If I have the shaft replaced the yard needs to correct length to order the replacement.
Anyone have knowledge of the length so I can save a haulout just to measure the shaft?
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Regards,
John Stevenson
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John
Exact length varies somewhat by propeller and may vary slightly from boat to boat. Having a little variation in the coupling gap is most likely caused by a bent shaft but not always. Your coupling may be bent. I suggest pulling the shaft and send it out to a prop shop that specializes in shafts. They can check the shaft to see if its true and can remachine an exact replacement. Before you pull the shaft, measure the distance between the prop and the strut. Discuss this with your prop shop to see if its correct. The new shaft may need to be a slightly different length to adjust this correctly. This distance is critical to smooth operation. Now would be a good time to consider adding a line cutter as it requires a little more space between strut and prop. Its also a good time to consider a dripless stuffing box since the shaft will be out.You should send out your coupling too. If they say that the shaft and coupling are both OK, you may have a bent flange on your V-drive. The coupling or V-drive flange can get bent if someone tries to remove the shaft improperly. A common way to remove the shaft is to separate the coupling by about 3 inches and stick a socket in there. Tightening the screws will then force the shaft to slip out of the coupling. If care isn’t taken to tighten the screws evenly, its easy to bend the coupling and/or V-drive flange.
Regards
Rich
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I agree you have to pull it to do it right. I paid just under $900 for a new shaft, prop nuts, Walter Gear coupling and fitting the coupling to the shaft.
If you really wanted to not measure it you can try to contact the guy I used and see if he'll make you an exact copy. Here's his info and the info on my shaft as he observed it before replacement.
“Gary Ives – The Prop Shop” < ([email][/email])
Shaft Target Diameter: 1-1/2″Shaft length: 66″
Observed Diameter delta: Stuffing box area -0.015″
Cutless bearing area -0.011″
Shaft is -.007″ to -.009″ in middle
Straightness delta: 0.004″
Anything else I should be looking at?
1. Your cutless bearing area is .011″ under 1.50″.
According to Navy specs, for an 1-1/2″ shaft, you should have .004″ to .010″ shaft to bearing clearence. A new bearing is built with .010″ to .015″ clearence. If you add the .011″ that the shaft is under diameter in the cultess bearing area, that puts you at .022″ to .026″ for bearing to shaft clearence.
Give me a call at 425-745-1700 and we can talk.
Thanks, Gary
-p
On Wed, Mar 10, 2010 at 10:57 AM, < ([email][/email])> wrote:
Quote:John
Exact length varies somewhat by propeller and may vary slightly from boat to boat. Having a little variation in the coupling gap is most likely caused by a bent shaft but not always. Your coupling may be bent. I suggest pulling the shaft and send it out to a prop shop that specializes in shafts. They can check the shaft to see if its true and can remachine an exact replacement. Before you pull the shaft, measure the distance between the prop and the strut. Discuss this with your prop shop to see if its correct. The new shaft may need to be a slightly different length to adjust this correctly. This distance is critical to smooth operation. Now would be a good time to consider adding a line cutter as it requires a little more space between strut and prop. Its also a good time to consider a dripless stuffing box since the shaft will be out.You should send out your coupling too. If they say that the shaft and coupling are both OK, you may have a bent flange on your V-drive. The coupling or V-drive flange can get bent if someone tries to remove the shaft improperly. A common way to remove the shaft is to separate the coupling by about 3 inches and stick a socket in there. Tightening the screws will then force the shaft to slip out of the coupling. If care isn't taken to tighten the screws evenly, its easy to bend the coupling and/or V-drive flange.
Regards
Rich
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Owners no more...
Thanks Dawn and Patrick! -
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Thanks, Rich, Patrick & Hank. I'll file this information away for another month or so. I had the chief mechanic in the yard look at the gap, and he said I can probably live with it for awhile (0.003″ gap). Looks like I might also need a V-Drive re-build (don't ask why I didn't have the V-Drive replaced when I repowered 2 years ago). I don't think I'll throw any more money into this V-drive and will likely replace it with the V-26.
So bottom line, the shaft has been aligned as best the yard can do and I'm taking the boat back to New Bern for a couple of months to finish some planned boat projects and few new ones (e.g., crack in one of the compression fittings on the cold freshwater manifold dumping almost a gallon of water into the bilge each day). You know something is not right when the bilge pump comes on 2 days after the boat has been hauled.Then I'll address the V-drive, shaft issues in May before heading north.
On Wed, Mar 10, 2010 at 2:40 PM, hs < ([email][/email])> wrote:
Quote:John,
My shaft is 65 1/2″ long.
Hank S.
Shay #90— On Wed, 3/10/10, John Stevenson < ([email][/email])> wrote:
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John,
From my experience, even though the gap is small, you may have some vibration at high shaft speeds. I think .003 is within the V-drive alignment tolerance, but its almost impossible to get the darn thing aligned that close as it is. If you add .003 to your best effort, I think you’ll be out of spec.
As discussed in great length, the RV-26 is not a direct drop-in replacement. I agree that its not practical to toss money at the old RV-20 since the cases are no longer available so you’re stuck. Once you replace the thing, you should be home-free. Feel free to call me if you have problems retro-fitting the v-drive. I think the most difficult part was removing the ole splined shaft from the jack-shaft. You’ll be tossing the old splined shaft. If it won’t budge, Weld a bolt to the end of the thing and slip a pipe down its length. Then drop a washer over it and a nut. Tighten the nut to pull the shaft out.
Regards
Rich
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Thanks, Rich.
I've started my research on this subject with your web-site. Interesting, the greatest vibration I get is in gear at idle throttle. When I increase the throttle to 1000 RPM the vibration goes away. This makes me believe this condition has been there for a long time. The W60 idled at 1100 and may have been masking the vibration. I never noticed it until the Yanmar repower, which idles at around 700.On Wed, Mar 10, 2010 at 3:45 PM, < ([email][/email])> wrote:
John,
From my experience, even though the gap is small, you may have some vibration at high shaft speeds. I think .003 is within the V-drive alignment tolerance, but its almost impossible to get the darn thing aligned that close as it is. If you add .003 to your best effort, I think you'll be out of spec.
As discussed in great length, the RV-26 is not a direct drop-in replacement. I agree that its not practical to toss money at the old RV-20 since the cases are no longer available so you're stuck. Once you replace the thing, you should be home-free. Feel free to call me if you have problems retro-fitting the v-drive. I think the most difficult part was removing the ole splined shaft from the jack-shaft. You'll be tossing the old splined shaft. If it won't budge, Weld a bolt to the end of the thing and slip a pipe down its length. Then drop a washer over it and a nut. Tighten the nut to pull the shaft out.
Regards
Rich
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John
Odd that you have vibration at idle speed. I don’t think I run the engine in gear at idle so I can’t comment. I have a folding prop, so idle isn’t a good choice. According to my seatrial notes, I’d be doing 2.5 kts at idle. I need to run at at least 1000 RPM for the alternator and refrigeration compressor to work right. That’s about 3kts. I’ve got a lower gear ration in my V-drive, so you’re pushing the prop a little harder at low speed. I don’t think I ever run the engine at idle unless I’m shifting gears.From my experience, if I’m just slightly out of alignment, the boat will vibrate at high speed, about 1000 shaft RPM. With a 2:1 gear reduction for a typical RV-20, that would be about 2000 engine RPM, maybe a little less depending on how far out you are. That’s probably at about 6.7 to 7.0 kts depending on sea-state. As I recall, it would smooth out if I backed off to about 6.5kts. With the alignment correct, the boat runs pretty smooth all the way up to hull speed.
Rich
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Rich,
Like you I don't run in idle, just when putting the engine in gear and changing gear. I immediately power up to at least 1000 RPM even when maneuvering out of the anchorage or dock. I do get vibration under way at around 1500, then it smooths out at 1800-2000 – my normal cruising RPMs at 6.5 – 7.0 kts. On my way back to New Bern tomorrow (about 25nm up the Neuse) I'll experiment with RPMs and see if anything has changed.On Wed, Mar 10, 2010 at 4:44 PM, < ([email][/email])> wrote:
Quote:John
Odd that you have vibration at idle speed. I don't think I run the engine in gear at idle so I can't comment. I have a folding prop, so idle isn't a good choice. According to my seatrial notes, I'd be doing 2.5 kts at idle. I need to run at at least 1000 RPM for the alternator and refrigeration compressor to work right. That's about 3kts. I've got a lower gear ration in my V-drive, so you're pushing the prop a little harder at low speed. I don't think I ever run the engine at idle unless I'm shifting gears.From my experience, if I'm just slightly out of alignment, the boat will vibrate at high speed, about 1000 shaft RPM. With a 2:1 gear reduction for a typical RV-20, that would be about 2000 engine RPM, maybe a little less depending on how far out you are. That's probably at about 6.7 to 7.0 kts depending on sea-state. As I recall, it would smooth out if I backed off to about 6.5kts. With the alignment correct, the boat runs pretty smooth all the way up to hull speed.
Rich
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