Bottom Fin Needed or Not

Discussion in 'Questions/Comments' started by Phil Klass, Aug 8, 2014.

  1. Phil Klass

    Phil Klass New Hydrodyner

    Joined:
    Jul 23, 2014
    Messages:
    9
    Boat Model and Year:
    Hydrodyne Flat Top 1969
    Looking at buying mid seventies 17' 6" Hydrodyne with floor rot in seat area. Bottom fin is missing and gap in keel area where fin was, appears to be glassed over, but can still see gap.

    The boat is set up for twins but has no motors. It has the steel over the transom and didn't look out of line. Would put a single on it and maybe at some point maybe do a restore. Don't want to get it and have to do a restore immediately because the fin is gone.

    I some what understand the importance of the fin, but should I even consider using the boat without it because the performance will be compromised? . . . . And, Hence should I even consider buying?
     
  2. jim

    jim Hydrodyne 18 Specialist

    Joined:
    Jun 14, 2006
    Messages:
    2,297
    Location:
    FL
    Boat Model and Year:
    77 Dyne 18 I/O converted to Outboard
    It will track better with the fin, but I would not think that it is unsafe without it. Reach into the motor mounting holes with a small screw driver or pocket knife and check for rotten wood.

    jim
     
  3. tj309

    tj309 Composite Specialist

    Joined:
    Jul 19, 2010
    Messages:
    397
    Location:
    LA (lower Alabama)
    Boat Model and Year:
    1972 18' Hydrodyne
    Ski Team:
    Former Hodag Water shows
    The boat will work fine without a fin but it would not be a true Hydrodyne. A Dyne can turn on a dime because of the fin. If you have ever tried to whip a skier around the boat you know what I am saying.

    My project started because the fin area leaked and eventually rotted the core and everyting else - see my 1972 Keel Up Restoration thread.

    Taking an old boat like a classic Dyne may be a bit more than you want to chew on.
     
  4. Phil Klass

    Phil Klass New Hydrodyner

    Joined:
    Jul 23, 2014
    Messages:
    9
    Boat Model and Year:
    Hydrodyne Flat Top 1969
    Is there a source for replacement Hydrodyne bottom fins?
     
  5. dynebob1

    dynebob1 Boat of the Month

    Joined:
    Jun 22, 2006
    Messages:
    557
    Location:
    Glen Ellyn, Illinois
    Boat Model and Year:
    1998 18 OB RUA- 250XS.and 1997 Twin Rig /225 optis
    Try Tom Miller @ Fiberglass Products & Boat Repairs
    (260) 337-5636
     
  6. Phil Klass

    Phil Klass New Hydrodyner

    Joined:
    Jul 23, 2014
    Messages:
    9
    Boat Model and Year:
    Hydrodyne Flat Top 1969
    Shortly after I posted my question, I happen to find a posting on this site about skegs or as I have been calling it, a bottom fin.

    It listed Tom Miller as a source for them. Since the phone number was there I gave him a call. He no longer has any and no longer makes them. His die for making them broke many years ago and he never made a new die.

    Sounds like they have to be made from scratch now.

    If any one ever takes theirs off they should trace it, measure it and put the diagram on this Web site.
     
  7. Must-Ski Motors

    Must-Ski Motors Hydrodyne 20 Specialist

    Joined:
    Sep 1, 2006
    Messages:
    512
    Location:
    Beaver Dam
    Boat Model and Year:
    2008 Dyna-Ski 20' Open Bow, 3.4L 250 HO
    I've got one and can get more.
     
  8. kevinb

    kevinb Elite Hydrodyner

    Joined:
    Sep 10, 2006
    Messages:
    437
    Location:
    Brookfield, WI
    Boat Model and Year:
    75 HD 18' I/O SOLD & 1985 HD 20' (Boat #2) I/O 350
    Ski Team:
    NA
    That's really cool Must-ski (as in Erik, correct?) if there is a "tracking fin" out there with your club, and they are still available. I think we talked several years ago when I co-owned a boat with Lynn M. of Fishers in Watertown, WI at the time (or maybe not?).

    Phil. They are "tracking fins", not to be confused with the skeg on the bottom of foot/lower unit of the outboard motor or outdrives. Tracking fins serve a very specific purpose and are all about keeping point/direction, as in they compensate for the forces of a skier pulling out to cut back the other direction, and also assist with steerage in the corners when coming around to change directions ( if the boat is kept on a plane).

    With the 73 that I owned with Lynn (165 hp i/o), we were handed the fin uninstalled at the purchase. After the first outings, it was very apparent with aggressive slalom skiers behind the boat at 32 to 36 mph, and barrel rolls in the corners to come back into the track/wake, and aggressive pull-outs by the skier, that the fin was missing and was definitely needed to be installed. The flat bottom characteristics of the 18 and soft chine allowed for a lot of leverage for the skier to pull the boat around without a fin on a pull out, and a lot of slip and roll on a turn in the corners were kind of sketchy. I'd opt for a tracking fin and the fun, stability, and confidence it will bring to the person behind the wheel.

    If you can get one, It will be night and day with short-line slalom open water practice runs.

    Just my $0.02,

    Kevin-
     
  9. dynegreg1

    dynegreg1 King Dyner

    Joined:
    May 31, 2006
    Messages:
    587
    Location:
    Pingree Grove, IL
    Boat Model and Year:
    1990 Hydrodyne 20 Open Bow
    Ski Team:
    Skimmer/Aquanut alum
    Erich,

    I need a fin. Get back to me.

    Thanks,

    Greg
     
  10. Steve Marcus

    Steve Marcus New Hydrodyner

    Joined:
    Jun 12, 2014
    Messages:
    7
    Boat Model and Year:
    1972 18'
    Ski Team:
    Blue Spring Lake Ski Club
    Guys, after a year long restoration of my '72 Tournament Skier, I launched today only to break off the tracking fin (no idea where or how). Would love to know where i can get one if mine is lost forever. Thanks much.
     

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