Shaft alignment and rudder torque

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I aligned the engine to the shaft in my boat recently.  The engine wound up all the way to port on the mounts to align properly.

I have also been having trouble adding steering torque by filing my rudder.  I'm filing on the port trailing edge of the rudder to add steering torque to port.

I'm wondering if the two could be related.

With the engine to port the shaft is pointing such that the prop is trying to push the stern to port, or into a slight turn to starboard (right).

I want to add left hand torque to my steering, which is opposite of this torque due to mis-alignment of the shaft in the boat.

I checked the shaft going through the bottom of the boat and it is offset to port so needs adjusting anyway.

Just wondering if the alignment could be affecting the steering?  Seems as though it could to me.

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Carl Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: February-03-2005 Location: United States Status: Offline Points: 28	Post Options Post Reply Quote Carl Report Post Thanks(0) Quote Reply Topic: Shaft alignment and rudder torque Posted: May-18-2009 at 10:38pm
	I aligned the engine to the shaft in my boat recently. The engine wound up all the way to port on the mounts to align properly. I have also been having trouble adding steering torque by filing my rudder. I'm filing on the port trailing edge of the rudder to add steering torque to port. I'm wondering if the two could be related. With the engine to port the shaft is pointing such that the prop is trying to push the stern to port, or into a slight turn to starboard (right). I want to add left hand torque to my steering, which is opposite of this torque due to mis-alignment of the shaft in the boat. I checked the shaft going through the bottom of the boat and it is offset to port so needs adjusting anyway. Just wondering if the alignment could be affecting the steering? Seems as though it could to me.

eric lavine Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413	Post Options Post Reply Quote eric lavine Report Post Thanks(0) Quote Reply Posted: May-18-2009 at 10:51pm
	get a good reference point from shaft to chines and measure, how much do you think its off?, look at your strut bushing and respond if its loose on one side and squeezing the other and vica versa on the back side
	"the things you own will start to own you"

8122pbrainard Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045	Post Options Post Reply Quote 8122pbrainard Report Post Thanks(0) Quote Reply Posted: May-18-2009 at 10:52pm
	Carl, Is your strut bent?
	54 Atom 77 Tique 64 X55 Dunphy Keep it original, Pete <

Fl Inboards Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Grand Poobah Joined: January-20-2008 Location: United States Status: Offline Points: 2119	Post Options Post Reply Quote Fl Inboards Report Post Thanks(0) Quote Reply Posted: May-18-2009 at 11:26pm
	Carl when you aligned your shaft did you pull your shaft packing assembly loose and run it up the shaft to expose where the shaft comes thru the shaft log? This will tell you if you are in the middle of the shaft log or not. I have seen motors that aligned all the way to one side or another and still be in the middle of the shaft log. this is usally because the stringers are not installed in the boat correctly. However I have also seen motors align and be running on the log, if this is the case then something is not straight with the strut. As for the the rudder torque you are only petting the trailing edge with a file, put it back in the tool box and get out the grinder and grind a nice light straight bevel on the port side trailing edge.
	Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise. 1993 Shamrock "fat" 20. 2008 Nautique 196 5.0

Carl Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: February-03-2005 Location: United States Status: Offline Points: 28	Post Options Post Reply Quote Carl Report Post Thanks(0) Quote Reply Posted: May-18-2009 at 11:28pm
	I'll measure Wed/Thursday when I go to the lake. From memory I'd say the shaft enters the bottom of the boat maybe 3/16 to the port side of center. By the time you get to the front of the engine that could double to 3/8 with the extra distance from the strut. With the coupler unbolted the shaft turns easily, so I don't suspect a problem with the shaft bushings, but I'll check those too. I don't think the strut is bent. I have had the strut off to replace the bushings. I'm guessing I didn't get it back on in exactly the right orientation. All that said, could the shaft mis-alignment WRT the boat cause the loss of steering torque I see?

eric lavine Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413	Post Options Post Reply Quote eric lavine Report Post Thanks(0) Quote Reply Posted: May-18-2009 at 11:41pm
	I really dont think so, an 1/4" over at the engine only would cock the prop not even 0.100 the engiine would have to be a couple inches to one side to notice, if at all
	"the things you own will start to own you"

BuffaloBFN Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094	Post Options Post Reply Quote BuffaloBFN Report Post Thanks(0) Quote Reply Posted: May-19-2009 at 9:59am
	I'd loosen the strut up and see if you have some play in the mounting holes. If so, put the engine back in the middle and take a look at the strut. Also, these stuts get bent and/or twisted pretty easily!
	1988 BFN-sold "It's a Livin' Thing...What a Terrible Thing to Lose" ELO

Carl Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: February-03-2005 Location: United States Status: Offline Points: 28	Post Options Post Reply Quote Carl Report Post Thanks(0) Quote Reply Posted: May-19-2009 at 11:33am
	Thats what I was planning to do. Break the coupler, loosen the packing gland, loosen the strut mounting bolts and center up the shaft where it enters the boat. Tighten strut, adjust the engine mounts, and secure the packing gland. It needs to be adjusted even if it doesn't affect the steering. On detecting a bent strut, if the shaft goes into the boat in the right place then I'm assuming the strut isn't bent. Right? I'll report back with findings.

BuffaloBFN Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094	Post Options Post Reply Quote BuffaloBFN Report Post Thanks(0) Quote Reply Posted: May-19-2009 at 11:38am
	Before you take it apart, turn the rudder straight and sight up the centerline of the boat...rudder to skegs. Where is the driveline in relation to this?
	1988 BFN-sold "It's a Livin' Thing...What a Terrible Thing to Lose" ELO

8122pbrainard Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045	Post Options Post Reply Quote 8122pbrainard Report Post Thanks(0) Quote Reply Posted: May-19-2009 at 11:55am
	Carl, The strut could be bent and the shaft still could be centered in the hull hole/shaft log. Do eyeball the centers with the rudder like Greg has suggested. Have you bedded the base of the strut to the boat with any sealant?
	54 Atom 77 Tique 64 X55 Dunphy Keep it original, Pete <

Carl Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: February-03-2005 Location: United States Status: Offline Points: 28	Post Options Post Reply Quote Carl Report Post Thanks(0) Quote Reply Posted: May-19-2009 at 12:01pm
	I cleaned the bed and the base of the strut with acetone, then applied a real light film of sealant before reinstall. Also put a good bit of sealant in each bolt hole to seal out the water. Is there a good write up on the site for preparing a proper bed for the strut?

Shaft alignment and rudder torque

About CCF

Donate

Partners

Contact