Alisske
Senior Member
Thank you. Ill check it out. I just got a new prop shaft and thats the way it came from the prop shop. But thanks for looking out.
Cutlass Bearings
- Thread starter angus99
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Thank you. Ill check it out. I just got a new prop shaft and thats the way it came from the prop shop. But thanks for looking out.
rslifkin
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For prop install, I've seen the recommended method as using the big nut first to make sure the prop is fully seated. Then remove, install and tighten small nut, then big nut and cotter pin.
Comodave
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That is the way that I do it. But since his prop is already seated I omitted that step.
LarryM
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I believe I read in an earlier post that your shaft's are 1-3/4" in diameter. What was the length of the new bearing? I just checked the Johnson Duramax Cutless Bearing catalog and the bearings for 1-3/4" shafts are only available in a length of 7". If that's what was installed, I'd think you will be OK since it appears to be the "standard" length for that size bearing.
OP
OP
angus99
Guru
Thanks much, Larry. I’ve read that a second cutlass bearing can be cut to fit the remaining space inside a strut if a single bearing is too short. Not sure how many yards actually do that or if it’s necessary. I’m going to try to find out what they removed if that’s possible but it’s sounding like using a single, standard-sized bearing per strut is acceptable.
psneeld
Guru
I would point out that long shafts internally have pillow blocks only a couple inches wide for support and whip....
Sure shafts outside the hull have hydrodynamic forces....but I got to think a cutlass bearing of standard dimensions would be adequate....cutting one down would bother me more or if I knew my strut spacing was at max recommended. But having one an inch shorter than my strut cavity feels OK.
I would document, present to the yard and keep investigating even if the boat went into the water. If I found out somehow this is a bigger issue than thought....the yard would get to do it all over again.
Sure shafts outside the hull have hydrodynamic forces....but I got to think a cutlass bearing of standard dimensions would be adequate....cutting one down would bother me more or if I knew my strut spacing was at max recommended. But having one an inch shorter than my strut cavity feels OK.
I would document, present to the yard and keep investigating even if the boat went into the water. If I found out somehow this is a bigger issue than thought....the yard would get to do it all over again.
FF
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Folks that operate in shallow sandy water may find the shaft is worn , as well as the bearing.
There are cutlass bearings made to cure this , a collar is pushed into the bearing housing and a collar with the new bearing material slid on to the shaft.
The bearing could be considered inside out.
There are cutlass bearings made to cure this , a collar is pushed into the bearing housing and a collar with the new bearing material slid on to the shaft.
The bearing could be considered inside out.
OP
OP
angus99
Guru
I heard back from two folks that I respect greatly—Steve D’Antonio—who is well known here—and Bill Gladding, one of the best marine surveyors in the business.
Steve’s reply:
Common shaft bearings, there are others but Johnson Duramax’s Cutless model is the most well-known, are availed in a wide range of sizes; you can view the list here. https://www.duramaxmarine.com/pdf/CutlessBearingMS.pdf
I’m not sure of your DeFever’s shaft diameter, however, for 1.5” for instance, naval brass shell bearings are available in 6” length alone (they are available in two different outside diameters). If the strut bore is longer, it’s not unusual, and not harmful, to have a cavity on the leading edge. It can be helpful in funneling water into the bearing, however, it can also trap debris, so it should be checked when the bottom is cleaned by a diver and at haul outs.
You can read more about shaft bearings here. https://stevedmarineconsulting.com/cutless-bearing-etiquette-2/
Bill largely concurs with this and verified the standard/normal length of Johnson shaft bearings.
I appreciate all the replies and hope this discussion helps others with similar questions.
Steve’s reply:
Common shaft bearings, there are others but Johnson Duramax’s Cutless model is the most well-known, are availed in a wide range of sizes; you can view the list here. https://www.duramaxmarine.com/pdf/CutlessBearingMS.pdf
I’m not sure of your DeFever’s shaft diameter, however, for 1.5” for instance, naval brass shell bearings are available in 6” length alone (they are available in two different outside diameters). If the strut bore is longer, it’s not unusual, and not harmful, to have a cavity on the leading edge. It can be helpful in funneling water into the bearing, however, it can also trap debris, so it should be checked when the bottom is cleaned by a diver and at haul outs.
You can read more about shaft bearings here. https://stevedmarineconsulting.com/cutless-bearing-etiquette-2/
Bill largely concurs with this and verified the standard/normal length of Johnson shaft bearings.
I appreciate all the replies and hope this discussion helps others with similar questions.
