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Conference vicki::boats

Title:Powerboats
Notice:Introductions 2 /Classifieds 3 / '97 Ski Season 1267
Moderator:KWLITY::SUTER
Created:Thu May 12 1988
Last Modified:Wed Jun 04 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1275
Total number of notes:18109

1139.0. "Engine and Prop Shaft Alignment" by GLDOA::DBOSAK (The Street Peddler) Thu Dec 30 1993 09:42

    Folks -- Since U gave me so many tips on the E-Oil leak -- I thought
    I'd ask for some insight on Shaft Alignment.
    
    I stopped by the Scurvy Queen yesterday to check the tarp -- Of course,
    I locked on to the port shaft because tis a spring project --
    
    Background:
    
    The shaft from the stuffing box to the prop is about 8-9 feet long --
    About 8 inches from the stuffing box is the FIRST strut bearing -- Last
    spring, we had to replace that bearing sleeve --- Sooooo we pulled the
    prop, removed the first strut brearing (Behind the prop) and then slid
    off the little one -- Each of the bearings are attached to the boat
    with through-hull bolts in holes that don't look like there's any slop.
    
    I had the shaft straightened and then put everything back together --
    WHen I did that, it looked to me that the front/back alignment of the
    first strut bearing was off from the main (aft) strut bearing --
    Thinking that since the bearing is a rubber surface, any misalignment
    would be handled by the compression of the rubber -- We put the boat in
    the water and when we're running at plane, there is a vibration in the
    forward strut bearing area -- Suggests that the alignment may be the
    problem.
    
    Now for your insight:  I ain't doin' that again -- I want to go to a
    marine repair shop and have them align everything -- The problem is
    that I don't know if who I get is going to BS me or if they really know
    what they're doing -- What I'm looking for is information I can
    internalize so that when the mechanix starts giving me a song and
    dance, I'll know it -- R there any special alignment tools -- If there
    are and the mechanix doesn't have that, it will be a clue.
    
    Thanks in advance
    
    Dennis
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1139.1Easier than you may think - if that's the problemNOTAPC::BURGESSThu Dec 30 1993 10:5232
re             <<< Note 1139.0 by GLDOA::DBOSAK "The Street Peddler" >>>
>                                  -< SSSSSS >-

>    marine repair shop and have them align everything -- The problem is
>    that I don't know if who I get is going to BS me or if they really know
>    what they're doing -- What I'm looking for is information I can
>    internalize so that when the mechanix starts giving me a song and
>    dance, I'll know it -- R there any special alignment tools -- If there
>    are and the mechanix doesn't have that, it will be a clue.

	If its anything like my (little) inboard, then  NO ! 

	no "special" tools; just regular wrenches, some sort of pry 
	bar and some feeler guages ("gages" ?).  In fact its probably 
	less trouble to DO IT than to HAVE IT DONE - but thats just my
	personal preference.

	I can X'ox the relevant page from my manual, if you're barely
even a half adept mechanic (or mecanic wannabe) you'll be able to
understand it, internalize it and hopefully recognize any BS on the
subject.  So, gimme a dec internal mail stop, I have the manual here
at work - can put the page copy in the mail 2-day. 
 
>    Thanks in advance

	Y'Welcome
    
>    Dennis


	Reg

1139.2How many Struts?KAHALA::SUTERNever too Hot!Thu Dec 30 1993 11:4820
    
    Hey Reg,
    
    	I'm not entirely sure that the "Scurvy Queen" is the same as our
    "little" inboards.... Dennis mentioned the "*FIRST*" strut bearing...
    Does this mean that the prop shaft runs through more than one strut?
    
    	If so, he may be talking about alignment of the multiple struts
    rather than engine alignment. Of course, engine alignment can be
    and has been performed at the dock on Ft. Meadow pond. If the "Scurvy
    Queen" only has one strut per prop shaft then it sounds like a simple
    engine alignment which is possibly a 1/2 hour task and the only
    "special" tool required is a flat feeler gauge. Multiple struts....
    well that would be a different story...
    
    	Rick
    
    	And, yes vibration is easily caused by mis-aligned engines....
    
    
1139.3So, why did the shaft need straightening anyway ? (-:NOTAPC::BURGESSThu Dec 30 1993 18:5638
re              <<< Note 1139.2 by KAHALA::SUTER "Never too Hot!" >>>
>                             -< How many Struts? >-

	Well, yes....   and I had assumed (-:  

and it looks like there is a bearing 8 or so inches behind (aft of) the 
stuffing box and another one about "a long way" behind that.  
In any case, I had sorta extrapolated (look it up) that an engine 
misalignment could/probably WOULD lead to some sort of "shaft whip" 
since it represents a bending force to the shaft.  As we know, this causes 
vibration at speeds of   ....depends, say 2500 rpm and up ?
Scurvy Q  got twice as many shafts as our li'l botes and they're each 
about twice as long, they're probably a bit bigger around too, but I'd 
guess they're not too stiff to take on a bend from a mis-aligned engine.
I had also assumed.. that getting the struts themselves out of 
alignment is less likely  a) to happen  and  b) to cause noticeable 
vibes, only at speed.

   O'course, being hit by fast moving underwater obstructions 
negates/invalidates my assumptions (-:

	and of course, I should have enquired as to the original cause 
of the need to have that shaft straightened  ...

	I'd still check the alignment, li'l bote style - and/or in 
Dennis' case familiarize myself with the procedure so I could talk  
"bote mechanic'eze"  at the shop.  

"How different IS this to a ski boat alignment job anyway ?"  

"It can't be THAT much more time consuming, can it ?"  

"My buddies say that's a half hour job for amateurs with just wrenches
and feeler guages"   be careful with this one (-:


	Reg

1139.4thanksGLDOA::DBOSAKThe Street PeddlerMon Jan 03 1994 09:2518
    Folks:
    
    Thanks -- Yeah the shafts on the Queen are around 12 feet long -- I
    don't know why that shaft was bent or out of "plumb." 
    
    The distance between the forward strut and the aft strut is about 8
    feet -- My plan was to have someone align the struts with the shaft
    disconnected from the tranny.  I figured that would eliminate another
    variable.  I was going to align both engines this year.
    
      At launch, I was going to let the Queen sit for a week or so to let the hull get to her normal pe.
    
    Then I was going to do an Engine ALignment to the shaft -- And that U
    can do with feeler gauges.
    
    Thanks,
    
    Dennis
1139.5Dennis' note reformattedKAHALA::SUTERNever too Hot!Mon Jan 03 1994 11:1128
	Reformatted so we can read that overflow sentence..,..
    
              <<< VICKI::SIE$DATA1:[NOTES$LIBRARY]BOATS.NOTE;1 >>>
                                -< Powerboats >-
================================================================================
Note 1139.4              Engine and Prop Shaft Alignment                  4 of 4
GLDOA::DBOSAK "The Street Peddler"                   18 lines   3-JAN-1994 09:25
                                  -< thanks >-
--------------------------------------------------------------------------------
    Folks:
    
    Thanks -- Yeah the shafts on the Queen are around 12 feet long -- I
    don't know why that shaft was bent or out of "plumb." 
    
    The distance between the forward strut and the aft strut is about 8
    feet -- My plan was to have someone align the struts with the shaft
    disconnected from the tranny.  I figured that would eliminate another
    variable.  I was going to align both engines this year.
    
      At launch, I was going to let the Queen sit for a week or so to let 
    the hull get to her normal pe.
    
    Then I was going to do an Engine ALignment to the shaft -- And that U
    can do with feeler gauges.
    
    Thanks,
    
    Dennis
1139.6H&H fixes struts also!KAHALA::SUTERNever too Hot!Mon Jan 03 1994 11:2528
    
    Dennis,
    
    	If the prop shaft was bent, it had to meet with something harder
    than itself at one time or another. ie: Underwater obstruction, the
    ground, something...
    
    	Anyway, the real question is how the heck would a person line
    up those dual prop shaft struts which reside on the same prop shaft.
    The first thing that comes to mind is bending the struts to a point
    of least prop shaft rotational friction. Not exactly a scientific
    solution and probably less than optimal.
    
    	Gee, I wonder if some sort of laser alignment tool exists for
    multiple prop struts.
    
    	I bent the strut on the Nautique very slightly. H&H propellor in
    Salem straightened it, somehow. (it was off the boat) Maybe they have
    some form of alignment tool. Of course this method wouldn't work if
    the area where the strut bolts to the hull is deformed. But, it might
    be a good place to start since you needed to have the shaft
    straightened.
    
    
    Good luck!
    
    Rick
        
1139.7Da Expert Sez:GLDOA::DBOSAKThe Street PeddlerMon Jan 03 1994 14:4920
    Da Expert sez:
    
    Disconnect the shaft coupler from the tranny.
    
    Look at the rubber part of the bearing on both ends
    
    If the rubber is being squished, it needs alignment 
    
    Replace bearing AND shim to where rubber is not squished
    
    Put boat in water and let the set get out of it
    
    Align engines to shaft
    
    Any half-a##ed mechanix can du this (so the expert sez!)
    
    Done!
    
    Dennis
    
1139.8Laser alignment tool? SALEM::NORCROSS_WTue Jan 04 1994 12:5220
    Dennis, is this a wooden boat?  When I first launch my 15" wooden
    Century Resorter with it's 1' (showing before bearing) prop shaft,
    the alignment is off by a good half inch.  Once the boat swells,
    it lines up perfectly with a .030 feeler gauge.  If your boat is wood
    and not too big, I would launch with the prop shafts in place but
    disconnected. Let the boat swell for a couple of weeks and then haul it
    out.  Take the prop shafts to H + H prop for straightening and then use
    them to shim your two prop shaft bearings.  Re-launch boat and then
    perform the engine alignments.  Of course this is alot of time and
    money but if your boat is wooden it may have developed "hogging" over
    time which you will need to adjust for.  
    Of course if the boat is not wood:  
    
    Never mind.
    
    I have a book on inboard engine installation back in NIO.  I'll see if
    it says how to align long prop shafts.
    Meanwhile, Rick, let's develop that "laser alignment tool" before
    somebody else does!!
    Wayne
1139.9AlignmentSALEM::GILMANThu Jan 06 1994 07:414
    Wayne, is this a procedure which someone with an inboard wooden boat
    should perform every spring? If it is.... whew!
    
    Jeff
1139.10SALEM::NORCROSS_WThu Jan 06 1994 08:2819
    Jeff,  I was talking about what I might do if I owned the "Scurvy
    Queen".  I was also making an assumption that it was a wooden boat
    and would experience considerable shifting while swelling.  My
    15 foot wooden inboard has no strut bearings to deal with like
    Dennis's boat.  My alignment procedure is very simple.  I disconnect my
    prop shaft in the fall when I store the boat.  In the spring I let the 
    boat swell up for 4 - 5 days before I check the prop shaft alignment. 
    My boat seems to go back to the same "shape" every year because the
    last time I had to do any engine adjustment was three years ago when I
    swapped in the Warner Velvet Drive in place of the original Eaton
    reverse gear.  Dennis has to deal with multiple strut bearings and long
    (8'?) prop shafts.  This must be a BIG boat.  I just don't see how one
    could align that set-up without having the boat swelled first nor can
    one unbolt the strut bearings once in the water because they are
    thru-bolted.  I'm sure there must be some other way to do this than
    what I made up.  My book on inboard installations only mentions how to
    determine how many strut bearings may be needed.  It does not say how
    to align them.
    Wayne 
1139.11Not HoggedGLDOA::DBOSAKThe Street PeddlerMon Jan 10 1994 11:3421
    Folks:
    
     The Queen is a Woodie. I'm pretty sure she isn't hogging -- I kept her
    in the water last winter to ensure she got the set out of her hull
    after being dry-docked for 6 years.  That meant she was in the water
    for about 15 months solid.
    
    Next spring I'm going to put her in the water with her shafts
    disconnected.  I'll tow her to her slip with the Scurvy Princess and
    let her sit a spell.
    
    If it was like last year, some damn duck is going to lay eggs on her and
    I won't be able to movethe Queen until I become a duck daddy.
    
    I'm on a mission on this one -- The Fleet Admiral always gives me grief
    'cause I'm a go-slow boater and she B a damn fast woman!  This year --
    It's a blazing 15 knots and if she carps, she's gonna be demoted to the
    Seaman gang
    
    Dennis
       
1139.12Cost Guess??NQOS02::nqsrv520.nqo.dec.com::fraschDon FraschWed May 01 1996 09:506
Anyone have an idea of roughly what it costs to have an "Engine Allignment"?? 
I have twin screws with v-drives, and the shafts coming through the hull are 
not centered in the ????? Bearing (can't remember its name).

Thanks,
Don
1139.13Hardest part is pushing the engine around...KAHALA::SUTERand now for something you&#039;ll really like!Wed May 01 1996 10:5819
Don,

	As mentioned earlier in this note, engine alignment is *REAL*
easy as long as you have adjustable motor and tranny mounts. Simply
loosen up the coupling that connects the tranny to the propshaft(s)
and use a feeler gauge to check for tolerance between the two halfs
of the coupling. Move the engine/tranny to bring it into spec.

	As for the cost, I'd guess a mechanic would use an hour
maybe 2 for both engines...

	The bearing in the strut is called a cutlass bearing.

Rick

ps. Guess I won't offer to help since you're in Rochester...

pss. You're mail address in the header appears to be no good.