Please note this thread has been inactive for 90 days. For the best results, please start a new thread.
Results 1 to 14 of 14
  1. #1
    Cadet rob5's Avatar
    Join Date
    Apr 2012
    Location
    Lakeland, FL
    Posts
    5

    Question Suggestions on how to reduce my boat from "sharking" at slow speeds

    Good morning, iBoats forum. I'm a new new member and I'm very glad I've found this resource. This is my first time posting so please don't beat me up too bad if I say something ignorant...

    Here's my issue - I have a small 18' sterndriven bowrider and at slow speeds it "sharks" back and forth considerably (I'm not sure if that's a real term, but that's about the best name I've heard which describes this effect). I can compensate with a fun little rhythmic steering maneuver, but this gets old very quickly (and thank heaven for power steering)... I've also tried different approaching speeds from plane to idle with no noticeable improvement.

    Am I doing something grossly wrong or does this have to do with the hull design? Any suggestions on how I can prevent or reduce this would be greatly appreciated.

    Thank you for your time and have a great day,
    Rob

  2. #2
    Senior Chief Petty Officer etracer68's Avatar
    Join Date
    Oct 2009
    Location
    SE, Wisconsin
    Posts
    799

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    Most deep v hulls "wonder" at low ( under 10mph ) speeds, but shouldnt at mid to planing speeds.
    1987 16Ft F/S Yar-Craft
    1987, 90HP Johnson/ (3) 1971-1972, 7.5HP Merc/ 1991, 4HP Mariner/1985, 2.2HP Merc (new never started)

  3. #3
    Petty Officer 1st Class BoatDrinksQ5's Avatar
    Join Date
    Feb 2012
    Location
    Minnesota
    Posts
    300

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    Mine also does that - (new to sterndrive) and noticed if i trim up high it helps a bit.

    Also if you just "let go....use the force"....don't steer - let it 'wander' you'll find it usually is a cycle and you end up pretty much going straight!
    2012 Tahoe Q5 SF (19'5", 4.3L Merc 190hp, Minnkota PD-V2 55#, Lowrance Elite-4)
    Projects: Hour Meter under dash, Engine compartment LED lights, & Side storage red mood light Thread

  4. #4
    Cadet rob5's Avatar
    Join Date
    Apr 2012
    Location
    Lakeland, FL
    Posts
    5

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    Quote Originally Posted by BoatDrinksQ5 View Post
    Mine also does that - (new to sterndrive) and noticed if i trim up high it helps a bit.

    Also if you just "let go....use the force"....don't steer - let it 'wander' you'll find it usually is a cycle and you end up pretty much going straight!
    Excellent... Thanks BoatdrinksQ5, I'll try that.

  5. #5
    Master Chief Petty Officer jdlough's Avatar
    Join Date
    Jul 2006
    Location
    Eastern Shore, Md
    Posts
    802

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    Nauticus Smart Tabs help this (and other things).

    Kinda like the fletching on arrows keeps them going straight.

  6. #6
    Commander
    Join Date
    Nov 2005
    Location
    Midway, Ga
    Posts
    2,339

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    I is the nature of the beast, deep V single prop, they all wander at low speed. We the operators usually make it worse by trying to correct it. Smart Tabs will just about stop that from happening and they will do a lot of other good things for your boat.
    http://www.facebook.com/iloveboating


    http://myboat.wikispaces.com/
    2004 Sea Ray 185 Sport, 4.3L,190, Alpha
    1994 GMC 4X4 1500, 5.7L

  7. #7
    Lieutenant Junior Grade mnypitboat's Avatar
    Join Date
    May 2010
    Location
    DeLand, Florida, United States
    Posts
    1,047

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    I second the Smart Tabs on this issue. It will also help your on plane porpoising as well. They are an inexpensive alternative to real trim tabs for smaller boats and really do a lot to help many minor issues.

  8. #8
    Moderator QC's Avatar
    Join Date
    Mar 2005
    Location
    Chino Hills, CA
    Posts
    20,717

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    For clarity, any trim tab setup, full down will help with displacement speed wander.

    Because you mention wander at planing speeds, I think you should search for info regarding your gimbal ring in the appropriate engine and drive section (Mercruiser? Vovlo? OMC?).

    Oh, and welcome aboard!!

  9. #9
    Cadet rob5's Avatar
    Join Date
    Apr 2012
    Location
    Lakeland, FL
    Posts
    5

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    Thank you all very much for your suggestions. I really appreciate your time and will look into the smart tabs.

    thanks again,
    Rob

  10. #10
    Captain Philster's Avatar
    Join Date
    Sep 2009
    Location
    Dutch Neck Farms, DE
    Posts
    3,299

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    rob5, what make of boat is that in your avatar?

    I keep mental notes of brands/hulls that have issues on plane.
    Checkmate 2400BRX/Optimax 300xs
    .
    Alumacraft 17 w/ Merc 40 4S

    Date an I/O, but marry an outboard!©


  11. #11
    Cadet rscot138's Avatar
    Join Date
    May 2012
    Location
    Michigan's UP
    Posts
    3

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    I've heard this called "Bow Steer" and "Wander" before also. It always seems like the more you try to correct it, the worse it gets.

  12. #12
    Cadet rob5's Avatar
    Join Date
    Apr 2012
    Location
    Lakeland, FL
    Posts
    5

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    My boat is a 1996 Starcraft 1810 with a 4.3L Mercruiser V6. I'm purchasing the Nauticus Smart tabs and can't wait to try them out.

  13. #13
    Cadet rob5's Avatar
    Join Date
    Apr 2012
    Location
    Lakeland, FL
    Posts
    5

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    Quote Originally Posted by rscot138 View Post
    I've heard this called "Bow Steer" and "Wander" before also. It always seems like the more you try to correct it, the worse it gets.
    That's true and it's definitely not a skill I want to develop any further.

  14. #14
    Chief Petty Officer jayhanig's Avatar
    Join Date
    Jun 2010
    Location
    Topsail Beach, NC
    Posts
    504

    Default Re: Suggestions on how to reduce my boat from "sharking" at slow speeds

    Quote Originally Posted by rob5 View Post
    My boat is a 1996 Starcraft 1810 with a 4.3L Mercruiser V6. I'm purchasing the Nauticus Smart tabs and can't wait to try them out.

    I think you're going to like them... a lot.
    Jay Hanig
    Topsail Beach, NC USA
    1985 Galaxy 176 Bowrider
    "No Good Deed"

Similar Threads

  1. "Clunk" at Higher Speeds
    By Sport Lido in forum Johnson & Evinrude Outboards
    Replies: 4
    Last Post: August 29th, 2011, 06:08 PM
  2. Wife said "smaller boat", not "bigger truck", but is V6 OK?
    By bhanson in forum Boat Topics and Questions (not engine topics)
    Replies: 36
    Last Post: April 17th, 2011, 01:55 PM
  3. Mercury 2000 75hp 2 stroke "bogging down at high speeds"
    By Blackwater25 in forum Mercury & Mariner Outboards
    Replies: 2
    Last Post: February 10th, 2011, 01:25 PM
  4. Will a "hydrofin" reduce transom strain?
    By tjandrews in forum Boat Topics and Questions (not engine topics)
    Replies: 12
    Last Post: September 6th, 2009, 10:08 PM
  5. 3.0 main bearing caps--Does the "F" stand for "Front" or "Flywheel"?
    By cheburashka in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 1
    Last Post: June 15th, 2009, 05:32 PM
  1. iboats Forum Directory - Over 100,000 forum posts organized by topic