Measurements of the Cutlass Bearing?
- Thread starter RSHunter27
- Start date
A race would keep it centered, and a thrust bearing would keep the pressure off the gearbox or transmission. Of course then you might as well put u joints in the mix. Then alignment wouldn't be such a meticulous item and even if it's slid out somehow slightly it would be no problem. Then you wouldn't have to have your engine at 15° or whatever. I must say it rather floored me back when I realized that when your shaft is engaged in forward that the prop is actually pushing the gearbox which of course is attached to the engine which incidentally moves the boat because the engine happens to be attached to the boat. Very inefficient not to mention stressful on parts that don't need to be stressed. Even just using something like a center support bearing used on most automobile drive lines would eliminate a lot of issues.
Even the use of the CV joint would be a good solution once you stabilize the prop once it enters the log or Stern "non"or-bearing.
Apparently, sailboat designers are not mechanical engineers and it seems as if they don't incorporate their wisdom into the mix.
Such a solution does exist, it’s just not commonly used on smaller and production boats (presumably due to cost) -
Aquadrive - Mack Boring & Parts Co
The Aquadrive antivibration system isolates the engine from the rest of your boat so noise and vibration are greatly reduced.
mackboring.com
Absolutely! that looks almost identical to what I am doing now other than I am replacing my old stuffing box with the new flex shaft seal boot , ordered that yesterday. Ordered the CV joint yesterday morning. I had already bought a thrust bearing and will be building a very similar barrier and then the propeller will be pushing the boat and not pushing the gearbox. I also purchased a universal joint. I really don't think I'll have room for it. I'll gain about three or four inches by using the new flex shaft seal. But the difference, in my thought process, and what they did was that I was going to add a universal joint ahead of the thrust bearing. By having forgiveness at both ends of the shaft before it enters the thrust bearing and then exiting the boat should provide a Ron Popeil scenario. I.e; set it and forget it. Now as sailboat owners we know we just don't forget to check on anything for very long. But I believe it won't be calling on me requiring attention. I am supplying pictures of complaints that I've got already and I will certainly shoot some shots of the whole finished product when complete.
Attachments
If you want to save a few inches more you can consider a Volvo dripless seal. That’s a very simple and compact design.
Do I correctly understand you'll be using the shaft bearing shown in your photo #2 :
........... as your thrust bearing ?
Well if it comes down to that we'll just have to wait and see. A CV joint takes up less space than a u-joint. Now they told me that this OJ flex seal that I bought that you can cut it down I think they said a couple inches. But I'll be on a wait and see on that idea. From the look of it I'm sure I could cut an insurance and a half off maybe. But I don't want to trim it down so far that I lose any utility. With all the things that I've been doing to my boat since I bought her is trying to reduce all the things that require heavy maintenance. I got rid of all the teak. Built a new companion way. And I have stainless steel rails for the top of the cabin on the deck. And so on. I'm retired now and I want to enjoy as much of the rest of my life as I can. I'd like to spend more time sailing and such not maintaining as much. I would rather deal with some difficult conditions in the Gulf or beyond then be dry docked and in a cycle of cyclical repairs. Anyway thanks again for your supporting article and comments. And as I said I will keep you all up to date on the progress and results.
Yes we went down today. It actually looks pretty good. The Cutlass bearing protrudes about an inch out of the strut toward the prop. So as we continue to rule things out, Monday I will receive the new soft shaft seal. It really appears as if the shaft is having its problem within stuffing box. Other than requiring a good bottom cleaning it looks pretty good under there. I ordered an oxygen tank and regulator that should be in within the next he's the professional that I like to do everything that needs being done on my boat at least once myself. Of course I'm an expert at changing out motors by this time. LOL
OUCH ! If the grinding has been taking place within the gland, you may have damaged the shaft surface which contacts the packing material. I don't believe you've mentioned anything about excessive gland leakage (not that I remember) so that shaft area may still be good.
IMO changing out the cutlass bearing is still premature as you don't know its condition. Mine is 24 YO and in better that new condition with 0.000" clearance clearance after 2300 operating hours. Why not solve the high friction problem FIRST and avoid any repeat work ? Repeat work like replacing the whole shaft for a high alloy SS shaft which guarantees you can forget it.
I'm still looking forward to seeing the area where the shaft exits the stern bearing.
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Yes Ralph it's a long video at this point I need to get some time to cut it up a little bit so it's manageable. I redid the stuffing box about a few weeks ago. I was getting a bit of a leak before that. But not anymore. I did it while in the water of course. It was not as drastic or dramatic as some had portrayed it. Just being prepared and working steadily... it was a non-issue. I sort of wrapped a rag a little bit around it just to direct the water into my bilge. I put a new bilge pump and hoses few months back. That new bilge pump ejects water as a projectile out of the side of the boat. Also I'm in the process of updating my hull above the water line. So at this point I have the porch side stripped and a couple of coats applied.
The "porch" side...
Sometimes I get a kick out of how the speech to text likes to quote me. Anyway I realized I actually didn't answer you and yes I agree with you I am not going to change the Cutlass bearing at this point. It doesn't appear to be necessary or the problem. so when the new soft flex shaft seal comes in I'm going to open up and take off the the old and of course put on the new. I think I'm going to see a lot there I will take pictures and keep you posted. But I I moved it back a little bit and I think there is some minor scoring but doesn't appear to be anything major I just think it's pressing on it. So we'll see!
Sometimes I get a kick out of how the speech to text likes to quote me. Anyway I realized I actually didn't answer you and yes I agree with you I am not going to change the Cutlass bearing at this point. It doesn't appear to be necessary or the problem. so when the new soft flex shaft seal comes in I'm going to open up and take off the the old and of course put on the new. I think I'm going to see a lot there I will take pictures and keep you posted. But I I moved it back a little bit and I think there is some minor scoring but doesn't appear to be anything major I just think it's pressing on it. So we'll see!
Just noticed I didn't reply to this question. Yes I'll be for all intents and purposes building a solid, sturdy retaining wall that that bearing will be attached to. That will stabilize the shaft between that point and the prop and not allow it to shift forward or backward. And then I'll be creating the forgiveness forward of that likely it will be to CV joints. I should be able to mount my engine level, as it was originally designed, before it's marinization. Imagine doing an oil change the good old-fashioned way... with gravity! I'm also expected better performance out of the motor without having to fight itself, pushing thrust out, only to have a major portion return. CV joints are designed to be able to handle as much as 40° of misalignment, using two of them, I am sure that 15 ,16, 17 18° of misalignment, well the affect will be major and the effect will be grand.
I've had the usual experience with bearings supporting radial loads but just not familiar with using bearing to withstand axial loads. Do you have any specs for that particular bearing for axial loading. Even worse, any idea what the axial loading on your prop shaft is when running flat out ? I think marine transmissions are designed for that.
I have no experience with tapered roller bearings other than what I read but this is what you require to accept axial thrust :
Is this what you have in the bearing casing you show :
Is this what you have in the bearing casing you show :
Aw crap !
All I see is a statement of radial loading. No mention of axial loading.
Do you have a manufacturer's part number to look up their complete list of specs for that particular bearing ?
All I see is a statement of radial loading. No mention of axial loading.
Do you have a manufacturer's part number to look up their complete list of specs for that particular bearing ?
@RSHunter27 ,
###quick edit###
The more I see of this project, the more I wonder why you are reinventing the drive train.
Simple is usually better, and while you may improve the overall drive train, you are adding a ton of complexity.
I would. Be going back to the basics….
1) remove the shaft and check for straightness, wear and corrosion / pitting. My 30 year old bronze shaft was in terrible shape…wear grooves in several places, circumferential cracks in many places. The shaft may need to be replaced.
2) check the cutlass bearing and importantly, the alignment. Hopefully the strut isn’t bent, broke or out of alignment…pain to get it right.
3) replace the old stuffing box with a dripless. That Johnson seal should work, but I have not used one. The
end that clamps to the stern tube is the end you can trim down. The (Large end) has a seal in it. You cannot cut that end off. Let us know how it works….I considered that before I bought a Volvo Penta rubber stuffing box….which I like.
4) engine alignment…hopefully final step.
At each step along the way, I would be checking to see if the shaft turns easily, and stays in the middle of the stern tube.
Greg
###quick edit###
The more I see of this project, the more I wonder why you are reinventing the drive train.
Simple is usually better, and while you may improve the overall drive train, you are adding a ton of complexity.
I would. Be going back to the basics….
1) remove the shaft and check for straightness, wear and corrosion / pitting. My 30 year old bronze shaft was in terrible shape…wear grooves in several places, circumferential cracks in many places. The shaft may need to be replaced.
2) check the cutlass bearing and importantly, the alignment. Hopefully the strut isn’t bent, broke or out of alignment…pain to get it right.
3) replace the old stuffing box with a dripless. That Johnson seal should work, but I have not used one. The
end that clamps to the stern tube is the end you can trim down. The (Large end) has a seal in it. You cannot cut that end off. Let us know how it works….I considered that before I bought a Volvo Penta rubber stuffing box….which I like.
4) engine alignment…hopefully final step.
At each step along the way, I would be checking to see if the shaft turns easily, and stays in the middle of the stern tube.
Greg
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