Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 20-05-2020, 09:33   #16
Registered User
 
OrangeCrush's Avatar

Join Date: Jun 2009
Location: Brooklyn, NY
Boat: Shannon Pilothouse 38
Posts: 745
Re: Moving motor sideways to correct alignment

Quote:
Originally Posted by Flatswing View Post
I would suspect the stern tube (“new last year”) as the culprit. Since boat is on the hard:
1) have the shaft & coupler checked/trued by a pro shop
2) use laser guide to ensure stern tube orientation hits center of transmission coupler within adjustment tolerance of slotted motor mounts
3) replace stern tube using laser guide if 2) not possible
Probably better to start with correct stern tube orientation rather than chasing the mounts excessively.
Thanks, Jeremy. Unfortunately I'm under a bit of a time crunch. If I don't go in the water by the end of the month the yard will have to move me to another spot at significant cost. When I consider some other factors it could even endanger my ability to go in the water this season altogether. Based on my access, correcting the stern tube is a way bigger job. If I can get the motor to match the stern tube, do you think it's such big disadvantage over getting the stern tube to match the motor? It would be orders of magnitude easier that way.
__________________

OrangeCrush is offline   Reply With Quote
Old 20-05-2020, 09:44   #17
Registered User
 
Dsanduril's Avatar

Join Date: Aug 2011
Location: Petersburg, AK
Boat: Outremer 50S
Posts: 3,151
Re: Moving motor sideways to correct alignment

Quote:
Originally Posted by OrangeCrush View Post
... Does anyone know how I can reliably check its straightness without specialized tools? .
The not-too-hard way, if you are going to a shop anyway, is to put the shaft in a lathe and spin it around with a dial indicator to measure runout. Do it at several locations along the shaft.

At home, if you have a flat surface you can roll the shaft along the surface and check clearance at various angles of rotation (look for gaps). You need to know that your surface is flat (this can be difficult in itself). A modification is to get a straight edge (big t-square, angle iron) and set the shaft on the straight edge. Check for gaps. Roll x degrees, check again, repeat. If you have no straight edge long enough you can get a reasonable estimate from a string pulled tight over the shaft. It's a bit harder to be accurate, but can give you an indication of a gross bend.

[Edit] Depending on direction a slightly offset stern tube may increase or decrease prop walk. To me, as long as the engine still stays on the bed, if you have to move it 5-10mm to compensate for a slightly changed stern tube it's not a big deal, as long as you get the alignment good throughout the entire system. If you have to move it enough that the mounts won't really be supported on the beds then you would have to start looking at the tube replacement - just my 2¢ - would I rather have it lined up perfectly? Yes. Could I accept a moderate change in the stern tube alignment as long as it could be adjusted at the mounts? Also yes, but YMMV.
__________________

Dsanduril is offline   Reply With Quote
Old 20-05-2020, 09:58   #18
Registered User
 
OrangeCrush's Avatar

Join Date: Jun 2009
Location: Brooklyn, NY
Boat: Shannon Pilothouse 38
Posts: 745
Re: Moving motor sideways to correct alignment

Quote:
Originally Posted by Dsanduril View Post
The not-too-hard way, if you are going to a shop anyway, is to put the shaft in a lathe and spin it around with a dial indicator to measure runout. Do it at several locations along the shaft.

At home, if you have a flat surface you can roll the shaft along the surface and check clearance at various angles of rotation (look for gaps). You need to know that your surface is flat (this can be difficult in itself). A modification is to get a straight edge (big t-square, angle iron) and set the shaft on the straight edge. Check for gaps. Roll x degrees, check again, repeat. If you have no straight edge long enough you can get a reasonable estimate from a string pulled tight over the shaft. It's a bit harder to be accurate, but can give you an indication of a gross bend.

[Edit] Depending on direction a slightly offset stern tube may increase or decrease prop walk. To me, as long as the engine still stays on the bed, if you have to move it 5-10mm to compensate for a slightly changed stern tube it's not a big deal, as long as you get the alignment good throughout the entire system. If you have to move it enough that the mounts won't really be supported on the beds then you would have to start looking at the tube replacement - just my 2¢ - would I rather have it lined up perfectly? Yes. Could I accept a moderate change in the stern tube alignment as long as it could be adjusted at the mounts? Also yes, but YMMV.
Thanks. Yeah I think I can rule out a dramatic bend. First of all, the misalignment doesn't change when I spin the shaft. It looks straight as an arrow against a T-square.

I agree with you. Too bad it's not offset in the other direction or it would help my prop walk, but it's definitely going to be a matter of millimeters and there is definitely good room to move the mounts without running out of strong reinforced real estate. It's not ideal but I think I can live with it.

The real lesson here is that I'm better off doing everything on the boat myself. I though that bringing it to a reputable yard would mean the job would be done right. Between the sloppy work with the packing material and this, I definitely would have been better off handling it myself. At least then I would know the imperfections and limitations rather than be surprised later (now).
OrangeCrush is offline   Reply With Quote
Old 20-05-2020, 19:05   #19
Registered User
 
Jesse's Avatar

Join Date: Apr 2008
Location: Oro Bay Puget Sound
Boat: Irwin sloop
Posts: 398
Re: Moving motor sideways to correct alignment

If the questionable workmanship screwed up the lateral alignment there is an equal likelihood that vertical is compromised as well, just sayin
Jesse is offline   Reply With Quote
Old 20-05-2020, 20:57   #20
Registered User
 
Boatyarddog's Avatar

Join Date: Nov 2014
Location: Olympia, Wa
Boat: 1979 Mariner Ketch 32-(Oberly build) - Hull 202
Posts: 1,061
Images: 2
Re: Moving motor sideways to correct alignment

Quote:
Originally Posted by Dsanduril View Post
Maybe in all the other stuff you allude to at the beginning of the post the shaft moved sideways a bit?

I would just take the bolts out of the maxed out holes and try it out. If you shift the whole engine to port (and that sounds like it is needed from the description) and it all works then you can look and see how much meat would be left if you slightly enlarged the slots, or look and see where a new bolt hole would land, then decide on which approach to take based on how it all looks.
Sound advise, always align the engine to the shaft, if the slots don't work where they are, you can dowel the holes and redrill where they will work.
Shaft tubes are some what offset on many vessels.
SV Cloud Duster
__________________
SV Cloud Duster
Boatyarddog is offline   Reply With Quote
Old 20-05-2020, 22:18   #21
Registered User

Join Date: Aug 2013
Posts: 255
Re: Moving motor sideways to correct alignment

Quote:
Originally Posted by OrangeCrush View Post
The coupling faces look extremely flat and parallel as they come together. The misalignment is most obvious with the shaft coupling off, as in the pic.

I can’t get back to the boat for a few days but I’ve got the shaft with me here. Does anyone know how I can reliably check its straightness without specialized tools?.
Here Is the jig I used. Support the shaft at either end on a Block of wood with two verticals either side to stop it rolling off. Then put a small nail or rod under the shaft To form a bearing surface that the shaft can turn on with minimal contact. You don’t need to worry about having the two ends lvel or square to the shaft, just make sure that the shaft is turning on the nail bearing so that there is minimal contact area between the shaft and the bearing that it is turning on and no wobble. Then take another block of wood and screw a screw one end of a straight edge to it so that the bottom edge of the straight edge is level with the top of the shaft. Position The straight edge across the shaft so that it rests on top of the shaft with 90% of the straight edge Hanging past the shaft, as shown in the attached photo. Now slowly turn the shaft and watch the very end of the straight edge. If there’s any bend in the shaft, the overhang will exaggerate it enough that you will be able to see it. Check for straightness at various points along the shaft and also move the supporting ends so that instead of the shaft being supported at each end, it is supported at one end and in the middle, and then check with the straight edge at the other end. Here’s a photo of the jig in action. Good luck.
Attached Thumbnails
Click image for larger version

Name:	C6EA85EF-CDFD-4E29-8168-AB9B55672EDC.jpeg
Views:	20
Size:	141.5 KB
ID:	215469   Click image for larger version

Name:	74D0D985-943F-4F9A-B760-51A4AC708405.jpeg
Views:	18
Size:	155.8 KB
ID:	215470  

osprey877 is offline   Reply With Quote
Old 21-05-2020, 02:02   #22
Registered User

Join Date: Sep 2018
Location: S. Texas, USA
Boat: 1972 Formosa 41, 41od 48 oa
Posts: 34
Re: Moving motor sideways to correct alignment

Those look like yanmar mounts, i just finished re installing a motor that had broken mounts, some yanmars call for different mounts on each side for torque reasons MAIN thing is that you have to be sure you have them turned properly and it's easy to miss the slight differences.some need to be turned 1 way the others fliped sround. ( slotted holes facing different directions) I believe that is the reason the old mounts failed they weren't properly positioned. once i got them all turned the right way the motor flushed right up good luck!_
capt.rob is offline   Reply With Quote
Old 21-05-2020, 04:16   #23
Registered User

Join Date: Feb 2020
Posts: 45
Re: Moving motor sideways to correct alignment

Hi
You might look at an AquaDrive or a similar. You can fit whilst afloat
John
johnn33 is offline   Reply With Quote
Old 21-05-2020, 04:16   #24
Registered User

Join Date: Feb 2020
Posts: 45
Re: Moving motor sideways to correct alignment

Apologies https://www.halyard.eu.com/aquadrive...ration-system/
johnn33 is offline   Reply With Quote
Old 21-05-2020, 20:21   #25
Registered User
 
OrangeCrush's Avatar

Join Date: Jun 2009
Location: Brooklyn, NY
Boat: Shannon Pilothouse 38
Posts: 745
Re: Moving motor sideways to correct alignment

Quote:
Originally Posted by capt.rob View Post
Those look like yanmar mounts, i just finished re installing a motor that had broken mounts, some yanmars call for different mounts on each side for torque reasons MAIN thing is that you have to be sure you have them turned properly and it's easy to miss the slight differences.some need to be turned 1 way the others fliped sround. ( slotted holes facing different directions) I believe that is the reason the old mounts failed they weren't properly positioned. once i got them all turned the right way the motor flushed right up good luck!_


Interesting... Yes they’re yanmar mounts and all the slotted holes are on the forward side. As suggested earlier, rotating some of them 180 degrees could give me the range of motion I need. Any chance you know what configuration was recommended or any way to find that info? The motor is a 2013 Yanmar 4JH5X1 in case that’s relevant.
__________________

OrangeCrush is offline   Reply With Quote
Reply

Tags
men, motor

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Docking monohull sideways advice wanted usdivers61 Monohull Sailboats 95 18-08-2019 13:49
DREAM/Plan went sideways T.Mark Meets & Greets 10 14-08-2019 01:47
How to find correct alignment? divezonescuba Propellers & Drive Systems 39 18-06-2016 06:13
Bottom sanding job seems to be going sideways on me gamayun Construction, Maintenance & Refit 42 19-04-2016 18:43
Ship Icon Only Goes Sideways AnchorageGuy OpenCPN 7 05-12-2012 18:56

Advertise Here


All times are GMT -7. The time now is 02:59.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.