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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

501.0. "I/O Handling" by HYDRA::BOUCHER () Wed Aug 30 1989 13:38

I've been an O/B owner for years and I'm going to upgrade to a bigger
boat and I/O this spring. I've been test driving I/Os and noticed that
they "hunt" for a direction at 5 mph much more than O/Bs. I noticed
that the Chaparal is worse than the 4Winns.

The Chaparal dealer claims that all I/Os have the same problem. The
4Winns dealer says that deep "V" hull designs are worse (i.e. Chaparal
design) and hull designs with the weight distribution more towards the
stern are the worst.

Is this a common I/O problem? Do O/Bs handle better than I/Os? Or are
these boats just poorly designed with misaligned stern drive units?
Questioning mind(s) want to know!

Ray
T.RTitleUserPersonal
Name
DateLines
501.1in the huntDSTEG::WENTWORTHWed Aug 30 1989 14:179
    My experience with I/O's has been that they all "hunt" at low speeds to
    some degree. A friends old tri hull was about worst case, my semi-V
    hull isn't too bad, and another friends 19 foot 4-Winns bow rider is 
    pretty good, but they all have the symptom. As far as handling; at
    speed the I/O seem very solid although without power steering there is
    a good deal of "torque steer" at varying power settings. There is an
    adjustment to reach neutral steering but it's only effective in a
    narrow range of throttle settings.
    The real solution; spend big bucks for something with twin engines.
501.2It's in the "v" NUTMEG::KLEINWed Aug 30 1989 14:399
    
    It's not the I/Os hunt so much as deep-V hulls with very high weight
    concentrations in the stern tend to 'fall off' the V frequently
    at very slow speeds. Result? Hunting at no wake speeds.
    
    Twin I/Os also hunt somewhat as well - they 'fall off' just like
    their single motor counterparts.
    
    
501.3I/O HANDLINGTHOTH::WRIGHTWed Aug 30 1989 16:037
    HI 
    I HAVE A 205 4WINNS AND I KNOW WHAT YOU MEAN BY HUNTING. IN MY BOAT
    THIS IS AT LOW SPEEDS ONLY,AT HIGHER SPEEDS IT IS FINE. IF YOU ARE
    LOOKING AT THE 4WINNS LOOK OUT FOR THE 3YEAR WARRANTY THERE ARE
    A LOT OF LOOP HOLES I FOUND THAT OUT THE HARD WAY.
    
    		BOB W
501.4(Tabs) fix for huntingWMOIS::D_BARRONWed Aug 30 1989 16:107
    
    	I have a 21' Four Winns that had the same problem at slow
    speed, much more than my 18'C Craft but the boat I have now
    is also a deeper V. That was before I installed Trim Tabs
    and with the Tabs all the down the Boat tracts stright as
    an arrow.
    
501.5THE SLOWER THE TOUGHERHPSTEK::BHOVEYWed Aug 30 1989 16:4212
    
    I have a 17' Sunbird, Corsair with a V6 I/O. Lots of weight back there.
    It hunts lots at no wake speed but handles excellent otherwise. I'v
    learned the right combination of speed and throttle control to dock it
    without to many problems, can be a bit-- though in current and winds.
    Overall in 2 years I dont really consider it a problem. I'v docked it
    moored it and put it on the trailer in the ocean and on rivers with good
    current and winds with no mishaps due to the control problems. I do
    like the I/O. Good luck...
    
    Bill
    
501.6I agreeGLDOA::BARTONWed Aug 30 1989 17:4113
     I guess I agree, an I/O will "hunt " a little bit at slow speeds.
    Mine has always done this, it just never bothered me. Of course
    I`ve never owned an OB, so I wouldn`t know the difference. My 
    opinion is to go with the I/O anyway, you`ll like youself for doing
    so. 
    
    
    				my .02 worth
    
    				jeff b.
   
    

501.7A hunting it will go...HYDRA::BOUCHERThu Aug 31 1989 09:396
    Thanks for the help. Looks like all I/Os hunt to some degree.
    Another reason to test drive a boat before buying. I'll
    probably go with the I/O expecting to "adjust" to it in time.
    I hope there are no other hidden little quirks about I/Os!
    
    Ray
501.8I/) w/trim tabs/hydr steeringBIZNIS::CADMUSThu Aug 31 1989 11:4477
    
    I've had both I/O and outboard and Inboard.  I used to run a 55 HP Bearcat
     4cycle outboard that had a Cast Iron Block- very heavy- the boat hunted 
    with that motor- apparently because of the weight in the stern. 
    I changed out to an 85HP Chrysler that weighed less and no more 
    problem at "no wake" speeds.
    
     Deep V's have more of a problem than modified V's or runabout "flat
    bottom" hulls. I have a 22' modified V with a 225 HP OMC v8- hunts a little
     at no
    wake speeds, but shifting weight to the bow almost eliminates it. I've
    operaterd two other boats with the same I/O - a deep V on a 21' and an 
    almost flat bottom 19'.  The deep V was a C craft and it really
    wandered- again moving the weight froward ( read mother-in-law) made a
    big difference. The "flat " bottom on the 19' G-white had hardly any
    noticable wander. When the trim tabs were down- it stopped completely.
    
     A number of people mentiomed torque steer- I must admit that on the
    older OMC I/O- I never had this problem. These boats had the OMC
    steering that uses a heavy rack and pinion with the steering arm coming
    right out the transom through a kind of ball joint and attaching right
    to the I/O housing. this I/O has a "ball gear" drive with no U joint
    and drive shaft like the current I/O's and could turn almost 90 deg-
    better manuevering than an Outboard. My dock mates- one with a 21' O/B
    and one with a 22' Mercruiser I/O get very envious-manuevering into
    our dock is hair raising even in calm weather.
      I've had I/O, O/B, and Straight inboard. For cruising and
    reliability, I'll take the inboard- but they stink on manuevering and a
    single screw  with a deep keel has lots of sideways movement when you
    tap the throttle.
      
     I'd go for the I/O. Todays's outboards are very complex and require
    so much special test equipment that you are forced into dealing with
    the dealer. The I/O's are basically truck engines and are simpler,
    quiter, and easier to work on. A surprising amount of bits and parts is
    available aftermarket. Even though the marine acessories are different
    than automotive, the auto parts stores do carry the aftermarket marine
    spares. I have purchased recntly through my auto parts dealer:
    marine head gaskets
    dist cap,rotor, points &condenser
    starter bendix
    alternator brushes
    and when my water pump went, I got an automotive pump on a Sunday
    afternoon that got me the rest of the way through the season. The
    difference in the automotive pump and the "marine " version was a 
    stainless steel back plate and a cast iron impellor on the "marine"
    version that cost about 5 times as much.
    
    I won't get into an argument here about the differences between marine
    an d automotive parts. But suffuce it to say that you can get 
    items like dist caps, points, condensors, brushes, starter drives,
    gaskets through most automotive stores that meet the "marine"
    requirements. Folks like Ward Marine also discount original parts also.
     
    The prices at the local auto parts store are also quite a bit different.
    My point is that parts  are much more readily availble and are less
    expensive for the I/O engines than outboards. The outdrives  or lower
    units are a wash- you are stuck with the dealer here.
    
      I'd go with an I/O with trim tabs and hydraulic steering. At slow
    speeds, kick up the tabs to minimize wander, and at higher speeds, the
    hydraulic steering should eliminate all if not most, of the torque
    steer.
    
    my 2�
    Dick
    
    
     
      
    
     
    
    
    
    
    
501.9QuestionBRWSKI::RESKERThu Aug 31 1989 12:353
    What's torque steer?
    
    tim
501.10spinning props cause 'torque'NUTMEG::KLEINThu Aug 31 1989 13:4113
    
    torque steer is what happens when the rotational forces of a turning
    propeller cause the boat to pull to the left - this pulling is felt
    in the steering in that you're pulling the wheel in the opposite
    direction to correct it. 
    
    unless you have power steering, you are constantly wrestling with
    the wheel to counteract the prop's 'torque'. always annoying and
    can be very tiring. 
    
    neat (but $) fix...get twins and counter-rotate one of the drives.
     
                       
501.11HAZEL::YELINEKWITHIN 10Thu Aug 31 1989 13:458
    Why is it that this 'torque steer' disappears when I'm 
    
                   on plane & the engine is trimmed out just right?
     
    Under these conditions the feeling of the steering wheel becomes
    "almost" as smooth as a friends hydralic steering.
    
    /MArk                (20' boat w/ 150 hp outboard)
501.12Action 'n reaction 'n such like stuff.ULTRA::BURGESSThu Aug 31 1989 13:5622
re                 <<< Note 501.11 by HAZEL::YELINEK "WITHIN 10" >>>

>>    Why is it that this 'torque steer' disappears when I'm 
    
>>                   on plane & the engine is trimmed out just right?
     
>>    Under these conditions the feeling of the steering wheel becomes
>>   "almost" as smooth as a friends hydralic steering.
>>    
>>    /MArk                (20' boat w/ 150 hp outboard)

	Torque steer comes from the hulls reaction with the water 
once the hull takes on a list to port (usually) as a result of the 
torque reaction between the prop and the hull (ultimately, via the 
engine mounts, stringers, etc.).   By the time the boat is on a plane 
the prop isn't meeting so much water resistance (you can tell, the 
engine spins faster for a given throttle opening (-; ) so there isn't 
as much torque reaction, hence less torque steer..... and anyway lotsa 
other schtuff changes when the boat planes (-; (-; (-; (-:

	R

501.13Compensation for torque-steer...?HAZEL::YELINEKWITHIN 10Tue Sep 05 1989 09:5721
    There's a zinc in the the shape of a small fin that screws into
    the lower end of my Yamaha 150 hp outboard. It is adjustable with
    the mid-point of its adjustment range where the fin(zinc) is parallel
    to the centerline of the boat, bow to stern. On the lower unit itself,
    next to where the fin screws in are graduations which aid the
    adjustment. My fin.. I assume, was adjusted by the dealer according
    to the boat the engine was pushing. This fin/zinc serves 2 purposes...
    the sacraficial anode and as a compensation (of some sort) for the
    torque-steer. 
    
    Can someone elaborate on this compensation and it's adjustment?

    When the dealer made such an adjustment...the Very First Time for
    a given size boat..., the proper position must have been arrived
    at by trial & error.
    
        Obviously, the amount of compensation initially adjusted will fall-off
    (degrade) as the zinc does its job. Therefore it is important to
    replace the zinc routinely.
    
/MArk
501.14Trial by evaluationFSDEV1::BSERVEYBill ServeyWed Sep 06 1989 14:578
    re: .13 
    
    I had minor torque steer at the start of this year with my 85hp ob. I
    messed with my anode/torque fin adjustment just to see. It was in the
    middle - between center and full starboard. Moving it back to center
    gave me even more torque steer, moving all the way to starboard gave me
    less than previously. I do believe your suppostion is correct - it's
    a matter of trial and evaluation. 
501.15Which way to lessen torque steer?BRWSKI::RESKERWed Sep 06 1989 16:336
    If you have torque steer to the port (left), which way do you direct
    the anode fin to lessen the effect?  My Mercruiser manual says to
    direct the fin in the direction of the torque steer but I would think
    the opposite.
    
    tim
501.16Fin = Rudder (small one)NUTMEG::KLEINWed Sep 06 1989 17:597
    
    think of the fin as a very small rudder which is always counteracting
    the 'to the left' pull of the engine/prop combo (assuming std motors
    and drives). Point the 'rudder' appropriately.
    
    Mitchell
                                                  
501.17Manual is rightHSKAPL::LUPANDERJan-Christian LupanderThu Sep 07 1989 02:3212
    Beg to disagree with .16 above.
    The trim tab is NOT an extra rudder but rather a servo trim tab
    affecting the outboard/outdrive position. That means that it is
    not turning the boat the way one would suppose but rather turning
    the drive. Put the tab with its trailing edge over to starboard
    will result in a force pushing the drive over to port (turning the
    whole tning clockwise) which again will turn the boat too to port.
    So the manual was right.
    The understand the same principle applies to airplane rudder/elevator
    trim tabs. Any pilot there that could comment?
    
    -jcl
501.18HAZEL::YELINEKWITHIN 10Thu Sep 07 1989 10:1217
RE: .15 by BRWSKI::RESKER                                        
    
>    My Mercruiser manual says to direct the fin in the direction of the
>    torque steer but I would think the opposite.
    
  I dug out my Yamaha Service Manual last night. The procedure for
    adjustment (according to MY manual) requires that you run the boat
    at max. speed with the engine all trimmed out nice....and let go
    of the steering wheel and take note of which way (port/starboard)
    the boat 'tends' to favor. This direction is the same direction
    you want to move the trim tab that we've been referring to as the
    anode/fin. My manual also stated that the 'fin' is adjusted at the
    factory to the first graduation(mark on the engine) towards the
    port side.
    
    /MArk
    
501.19my nickel on torque platesNUTMEG::KLEINThu Sep 07 1989 14:5431
    
    actually, beg to differ with previous (which, in turn, differed with 
    previous).
    
    if the tab were to change the angle of attack of the drive, that
    would not counter torque 'pull'.
    
    you are not trying to turn the drive, you are trying to turn the
    bow by forcing the stern in the opposite direction. in essence, you
    are trying to get the flow past the drive to cause a different
    reaction than it would without an additional plate. 
    
    if you bolt a curved (not hemispherical!) plate onto the drive, you 
    bolt it on in such a way that the plate's shape acts as an additional 
    force acting on the stern which affects the bow. to recommend that one 
    'points it accordingly' is correct. 
                    
    if the bow pulls to the left, you want to bolt a curved (to the
    outside) plate to the starboard side of the drive, pushing the stern
    to port and the bow to starboard.
    
    this may be one of those disagreements which is not a disagreement
    - all of this "which way do i point it" centers around 1. the mounting
    position of the tab, (either on the side or as a trailing edge of
    the drive), 2. the shape of the tab, and 3. reference point
    for 'pointing': leading or trailing edge of tab.
    
    mitchell 
    
    (when in doubt, 'do like the book says')
                 
501.20Yes, we disagree!HSKAPL::LUPANDERJan-Christian LupanderFri Sep 08 1989 02:0410
    We disagree! You very clearly state that the tab acts as a small
    rudder on the boat and you are quite right in your statements on
    how such a rudder should be mounted.
    I think the tab should be seen as a rudder on the drive putting
    a side force on that unit. (Note that the tab is mounted about as
    far from the steering axis you can get) If my thinking is right the
    tab mounting should be the opposite from what you suggest.
                                            
    -jcl 
              
501.21Look in the BookHAZEL::DELISLEFri Sep 08 1989 11:0714
    
    
    		This does seem like an easy issue to resolve.  I looked
    in the Merc owners manual under the heading "Adjustable Trim Tab
    and Galvanic Corrosion Inhibitor".  It states very simply that if
    the boat turns more easily (pulls in the extreme) to the left, move
    the trailing edge of the trim tab to the left when viewing from
    behind, etc.  This clearly 'trims' the drive to the right which compensates
    for what ever force is causing the symptom.  It works quite nicely
    I might add.
    
    
    Steve
    
501.22Help me understand?NUTMEG::KLEINFri Sep 08 1989 16:0513
    
    Sounds as if they use those tabs in a way I've not seen before.
    
    Is this tab bolted on to the side of the outdrive and then used to
    deflect water 'out', i.e. away from the drive?                 
    
    - or - 
    
    Is it bolted on to the trailing edge of the outdrive to act as a
    'secondary' rudder?
    
    Mitchell
            
501.23This might help, if you're an engineerSALEM::TAYLOR_MWatch your A$$ in NH--$peed Trap$!Fri Sep 08 1989 16:2914
    Mitchell,
    
    It hangs down from the anti-cavitation plate's rear-most surface,
    which essentially is right above the center after edge of the prop.
    Its purpose is to remove the rotational component of the vertical
    drive shaft's thrust from the pivoting mass of the out-drive unit. 
    It does this coincidently, using its own power. This method ensures
    that the tab will not affect the heading of the craft, using the
    turbulence of the prop as the correcting force.
    
    Mike, who's bitten his tounge long enuff!
    
                  
    
501.24When is a rudder not a rudder?NUTMEG::KLEINMon Sep 11 1989 12:169
    
    re:.23
    
    so, it ISN'T a rudder (or at least doesn't function the same way).
    
    as the saying goes: 'thanks, I needed that (explanation)'.
    
    Mitchell
    
501.25A rudder is a rudder is a ..HSKAPL::LUPANDERJan-Christian LupanderWed Sep 13 1989 02:5122
    Let's disagree some more..! It's a rudder!!
    
    Only it's a rudder on the drive, not on the boat.
    
    You could compare it to the situation where you reverse a car wit
    a long trailer, end result of turning the wheel is opposite from
    what you would get without the trailer hooked on. Or maybe it is
    more appropriate to think about a tug pushing a long barge. Only
    connection between barge and tug being something keeping the tug's
    bow in place but allowing the tug to pivot.                      
    Now if the tug (which corresponds to the outdrive) puts its rudder
    (the trimtab) over to right the tug will start turning to starboard.
    That in turn will force the stern of the barge to right and so put
    the barge into a turn to port. 
    (Oh! for these semantics, what nice noting subjects they make...)
        
    -jcl                                   
                                      
                                      
                                      
                                      
                                   
501.26HAZEL::DELISLEThu Sep 14 1989 11:268
    
    
    
    		Just like a trim tab on an aircraft.
    
    
    Steve
    
501.27I/O Steering and handlingGOLF::WILSONOn the boat again...Thu May 09 1991 11:0337
    Moved by moderator
    
================================================================================
Note 834.0                  I/O Steering and Handling                 No replies
MIZZEN::DEMERS                                       31 lines   9-MAY-1991 09:25
--------------------------------------------------------------------------------
I'm a new owner (Four Winns, Freedom 170), but not new to boating.  I grew up
with outboards and runabouts, but this is my first I/O.  I'm trying to get the
"feel" of the boat, so that I can determine what is normal and what may be a
problem in the future.  Some things I have noticed:

- The steering (manual) has a bit of slop in it.  I would say that the wheel
  moves about 2-3" before engaging the cable.  Should it be like my car
  steering (ie a bit tighter)?

- I've adjusted the trim tab to account for a tendency to turn to port.  The
  manual outlines adjusting a tab on the outdrive.  I am now at the lowest 
  number on the tab adjustment and I still have a slight pull.  I've tried
  to be scientific with it, making sure the load is balanced, no waves, 
  straight line, well trimmed.  If this is a normal tendency, then I'll
  just leave it alone.  I just wonder if the max'ed out trim tab is telling
  me that something else is wrong.

- Again, with the steering, making a turn is ok, but coming out of the turn
  requires some effort.  I could account for this as the outdrive having to
  push against the turn until I start to straighten out.  Maybe this is why
  some boats have power steering.  Maybe I'm not trimmed properly (this seems
  to be a black art, requiring lots of time to get the feel of the boat under
  different speeds and conditions).  All I have for a reference is an outboard;
  which I assume has much different handling characteristics.


Well, that's enough for now.  I'm enjoying the boat immensely.  Time now to get
a new ski and a fishing license!


/Chris
501.28I/O HandlingMIZZEN::DEMERSThu May 09 1991 11:2711
I just read the previous replies (thanks Rick) and I think I'm clear on the
steering.  The only outstanding question left is the play in the steering.
Pending comments here, I'll call the dealer.

Sorry for bringing up this topic again.  Dunno how I missed the note the first
time...

Thirty lashes...


/Chris
501.29exitEMMFG::THOMSWed Jun 15 1994 08:306
    I have a small handling problem with my old glass 15 foot runabout,
    60hp Johnson. At top end, wot, the boat will occasionally "roll"
    towards the port side. Would a fin help this situation by bringing the
    bow down a bit?
    
    Ross