Conference vicki::boats

    If you mean the "additional" cavitation plate, then pls read
    the note I've written back there somewhere. My opinion; Doel-fin
    isn't any good, you get better results by getting a better prop.
    Besides, it's *very* expensive, concerning its manufacturing costs.
    
    E T

    I'm not sure what you mean by expensive. Around here you can get
    one for under $100. Much less than a new prop.

    You've asked an interesting question. In my travels on the water,
    i'm beginning to see more of them. So far i've seen 3 in the last
    month. I don't have any info on wheter or not they work, but 
    the principle sounds. My guess is that it is a trim tab(s)
    that has been moved to the cavitation plate on the outboard.
    In principle sounds like it is supposed to give a lot more lift
    to planing hulls with less power required. 
    I'm not familiar with their advertising, but if they offer
    a money back guarantee for dissatisfaction, it certainly
    would be worth trying.
                                                               
    I'm not positive, but allegedly (sp) trim tabs may cause some
    drag, and may not be an advantage. Besides most of them are 
    electric hydraulic, another maintenance headache.
    The next time i spot one of these on a boat, i'll ask the
    owner(s) if they're satisfied, and publish their comments.
    
    I'm kind of curious myself.
    
    jim.

    Does anyone know how it affects the top speed?
    The ad said it would increase it with 10-20%, sounds to good to
    be true to me.

    I will vote a YES they do indeed work. I have one on my 19'
    Thundercraft Cuddy and it makes a world of difference when
    starting off. Time to plan with it is about 3/4's faster
    than without. As for cost they are under $60.00 from Overton's.
    The boat weighs 2800lbs and powered by a 205hp. Mercury Alpha 1
    drive.

< Note 173.5 by PHENIX::DUFFY >
     My boat isn't that heavy, it's somewhere in the neighborhood of
     2000, it' a VIP 178 F/S with a Force 125 with a SS 15 pitch.
     It doen't do to bad on the hole shot, when you with  both
     skies, but my brother-in-law is around 220 and likes deep water
     starts, on the slalom, so needless to say he drinks a little
     water before I can get him up, also the altitude of the lakes
     we ski is between 3300-4800 ft, so you run out of pony's
     real quick. 
   
     I need a solution to get the boat on plane sooner, without 
     repowering.  

     I might just give Doel Fin a try for next season.

     Mike
     

    A buddy of mine has a 22' Persuit wiht a 185 Hp Evinrude that he
    uses for charter work. With 6 adults on board, the rig was really
    slow coming on plane. Add a "Doel Fin"--- darn thing comes up faster
    with 6 now than it did with 2 before!!!! The neat part is its tied
    to the lower unit so any tilt-n-trim stuff still works well. I WILL
    have one on my rig next spring!!

     My father put one on his 22' deep vee and it really DOES work!
    The boat comes up on plane faster and it does have more top end.
    
    					Kenny

    
    
     I can attest to the benefit of these devices. I have a friend who
    had purchased a 21' Dixie with walk-around cabin and 125 HP Force
    O/B mounted on an external bracket. I had borrowed the boat in the
    past and  had been in it quite a bit the first two years he owned
    it.Once she would get up on plan the 125 pushed the Boat right along,
    but with 5 or 6 people on board, there was a lot of "running to
    the bow" to get the d######ed thing up on plane.
    
     When my boat ate it's outrdrive this summer, I borrowed this baot
    again and noticed that my friend had the Dole fin installed. I figured
    it was another gimmick until i got out of the mouth of the harbor
    and puored on the coal. The boat dropped on plne as nice as could
    be. The power trim was a lot more sensitive and managable and I
    swore the engine had been upgraded- nope, same engine, same prop.
    
     One of the previous comments said that getting out of the hole
    with 6 people and a Dole fin was like getting out of the hole with
    no fin and two people- I have to agree. I also suspect how well
    these things perform is a function of hull design and power/weight
    ratio.                                          
    

    
    
                  Must the cavitation plate of an O/B
                 be below the hull of the boat?? I was told
                 it made a big difference.

    RE: .10  
    
    Answer: No. Definately not if you have a fast boat, but if you have
    	    cavitating problems while turning it will probably help
    	    to lower the engine. The recommendations from the manufacturers
    	    is to mount the engine so the cavitation plate is at the
    	    the same level as the hull, then mount it higher to increase
    	    speed as long as you don't get any cavitation problems.
    
    Magnus

    Take care on setting O/B engine height! The cavitation plate is
    an active element which also help insure a smooth flow of cooling
    water to the engine's water intake!
    
    During a sharp turn at high speed (RPMs) you could lose cooling
    water flow...just when you can afford it the least. The hull design
    will play a major determining factor on how much height you can
    get-away-with. If it has lots of turbulence at the transom it will
    tend toward starving the cooling pump more quickly.
    
    Jerry
    

    I INSTALLED A DOEL-FIN ON MY 86' SEARAY 268 WITH MC260. WITH SIX
    ADULTS AND TWO MAXED OUT COOLERS I HAD TO THROTTLE UP TO 3800 TO
    GET HER OUT OF THE WATER AND THEN DOWN TO 3400 TO MAINTAIN PLANE.
    MY MAX RPM WAS 43/4400 WITHOUT THE FIN AND A ALUM.PROP.
    WITH THE FIN AND A STAINLESS PROP WITH THE SAME PARTY I'M OUT OF
    THE
    WATER AT 33/3400 PLANING AT 3200 AT REACHING 4700 MAX RPM.

    Moving from Alum. prop to Stainless will routinely give you up to
    about 500 RPM increase! Can't see how you can credit the Doel-Fin?
    The lower planing is likely a mixture of the effects of the new
    prop and fin. The stainless prop is structurally more stable which
    leads to smoother quieter and more efficient delivery of power.
    
    Glad you have achieved the improvement!
    Jerry
    

    
    RE .13
    
    86' Searay!!?? Nice boat......
    
    					rb

    REPLY TO 173.14 RE:DOEL FIN
    I CREDIT THE FIN WITH NOT HAVING TO FOOL WITH THE POWER TRIM ON
    THE OUT DRIVE. I KEEP IT SET ABOUT 10 DEGREES OUT OFF OF CENTER.
    IT MY BE AN ILLUSION TO ME BUT IT JUST FEELS BETTER AT THE HELM.

    RE.15
    I PAINT BOTTOMS BETTER THAN I TYPE. ITS A 1986 YOOSR.
    (YEAR OF OUR SEARAY)

    The January 1989 issue of TRAILER BOATS has a 'review' of
    DOEL FINs and friends.  The difference in results between the
    with and without tests was small.  I guess it's personal
    opinion as to whether the difference was so small as to be
    negligible.  TRAILER BOAT's summary was: it may work, and if
    it doesn't, you only spent $75.

    It follows their apparent policy of never saying anything
    negative about any advertiser.

    	- Lee

    Just attended the recent boat show here in Minneapolis a couple
    of weeks ago, and ran across a rep for the Sting Ray Hydrofoil
    Stabilizer made by Marine Dynamics, Inc., Overland Park, Kansas.  
    It's wing-type design makes it look like a whale's tail.  It bolts
    to the cavitation plate of either outboard or I/O powered boats.
    It's purpose is to keep the bow of the boat down when taking off.
    My 16' 90 Merc has a tendency to pop up on takeoff and porpoise
    in choppy water.  This seems like it might do the trick.  It sells
    for around $60-$80, and I've almost convinced myself to buy one.
  
    Has anyone seen/heard or had experience with one of these?
    
    In snow ... No boating!
    
    Rod

   Rod,

   See note 173

   keith

    What effect does the FIN have on the motor? I would think it might
    put more vibration or pressure on that out drive.  Also what happens
    to the manufactor's warrenty.

    I have a 26 ft Sea Ray Sundancer with a 335 hp OMC Cobra. I recently
    inquired about these planning fins. The one I was pursuing was a
    SHARK FIN. I was told that they will help somewhat but with trim
    tabs, a clean bottom and the proper prop I should not need the extra
    help. As to the last note entry, "What effect does the fin have
    on the motor ?" I was advised that the extra tension could tear
    the bottom off the outdrive as the casings are not built to with
    stand the extra pressure. I therefore cancelled the thought of using
    the fin. Can anyone remark on this ???
    
    Best Wishes and great boating.
    
    Stan Grodin
    DTN 244-7057
    

    I have a Wellcraft V20 Steplift w/ a new 200 Merc O/B that I use
    for trolling the coastal waters around Guam.  Added the Doel-Fin
    a couple of weeks ago and tried it with 2 different props (a 15"x
    15 p. & a 14.5" x 17 p.), both aluminum.  The 17p. prop seems to
    work much better, even though i can't quite hit max rated RPM (5200
    max w/ heavy load, 5400 - 5800 rated).  Since most of my time is
    @ trolling speed,  the easier plane doesn't make much difference
    to me, but fuel consumption has improved by at least a half gallon
    per hr., maybe better.  But get this, the handling characteristics
    in rough water are very much improved.  The improved handling &
    fuel savings make it well worth the $85 I spent for it.  I checked
    w/ my local Merc dealer before installing it, & he said it wouldn't
    hurt warranty.
    
    Regards, Skip B.

    I just recently added a stabilizer to my outboard.  There's an
improvement in the boats' performance, the only negative thing I can
say about the fin is that it takes a mile or two off of the top end.
Other than that, the boat rides smoother and skiers arn't getting
the drag they used to.  I'm getting much quicker starts.

    I ordered the stabilizer from Ski Limited for $63.95.  

Jeanne

                 
    			ANOTHER VOTE FOR DOEL FIN
    
    I HAVE A 28 FOOT BAYLINER CONTESSA 1984. INSTALLING A DOEL FIN
    THIS SPRING DID MAGIC. I CAN NOW CRUISE AT 2800 RPM VS 3400 LAST
    YEAR. ALSO LOW SPEED HANDLING IMPROVED. TOP END DID NOT INCREASE
    BUT CRUISING SPEED DID. IE 3400 RPM LAST YEAR RAN 28 MPH 2800 RPM
    THIS YEAR GETS ME 26 MPH.
    
    SAVING GAS: PAT BRADY
    

       I didn't get a Doel-Fin, but a Stingray for Xmas,
       finally got to use it this weekend. Wow what a       
       difference, getting on plane seemed to
       be instantaneous. In rough water
       it keeps keeps it steady like a rock.  
       Did loose about 5 mph on the top end, but
       my wife gives me heck when I run in that 
       range.    
       Turning also seemed to be helped, there
       doesn't seem to be any sliding in tight
       turns.  The ride has also improved, very
       little slapping on waves.
       
       

    
    I decided that it was time to give one of the "fins" a try. I have
    a Four Winns 235 Sundowner with a 260 hp OMC Cobra. I put the shark
    fin on the outdrive while the boat was still stored. Couldn't wait
    to put it in the water to test it out. Finally got it in and gave
    it a real test. I have to admit that it worked well....TOO WELL.
    The boat planed out faster than it even had....I was in heaven!!!
    The handling was also greatly improved.. However, I pulled up to
    the "sandbar" on Lake Winnisquam and when I tilted the engine up
    I was horrified at what I saw. The fin had provided so much lift
    that it had actually started to bend the cavitation plate. So, I
    took it off right then and there. 
    
    Has anyone else had any problem like that. I have talked to the
    manufacturer and they are going to sent a rep out (when they haven't
    said when) to look at the boat.
    
    All I can say is that it REALLY did the job it was designed to
    do..........a bit too well.
    
    Frank

    Well, I finally got around to putting a Stingray on.  I have
    a 17 ft V-hull center Console Campion with an 80 hp Merc.
    
    From reading notes where people lost speed, do you have powertrim?
    
    At what I call normal trim, my boat used to run around 37 mph.  Now with
    the fin on, it runs around 35 mph at the same trim, but on a much better
    plane.  Now, if I trim it up to just under cavitation angle, I can walk up
    over 40 mph with a heavy load.  In other words, with power trim and a 
    stingray, my top end has noticable improved.
    
    However, when I tak any kind of turn at this speed and high trim, I get
    massive cavitation.
    
    I'm not sure if I like it or not yet.
    
    The odd thing is that the fin seems to make water spray over the top
    of the fin and the stabilizer plate.  Do you folks observe this?
    
    I was wondering if my engine might be mounted a tad (1/2" or so) too
    high.  If so, I'd be more inclined to rip off the fin than move the
    motor.
    
    /brett 

       I'm looking for a bit of information.Many of you have probably
    seen or heard of the stabilizer that bolts onto the cavitation plate
    of your outboard that is supposed to act somewhat like a trim tab.The
    magazine in front of me right now calls it a "Hydrofoil GT".The
    advertisement makes all these claims that this device gets your
    boat on plane faster,gives a more stable ride,holds bow down,gets
    skiers out of the hole faster,etc.,etc.In case you aren't sure what
    it is,after you bolt it onto your motor,it looks like the wings
    of an airplane are sticking out.
       So what I want to know is if anyone has any first hand experience
    with this device.The text for the ad and the claims certainly seem
    to make sense,but you and I all know that most advertisements are
    predominantly BS.My particular boat is a 16' Starcraft bowrider
    with a 60Hp Johnson.It works well and I don't have any real problems
    with the things the foil is said to cure,but when no one wants to
    sit up front and it takes a few extra moments to plane out it would
    be good to get the downforce from the foil to pull the nose down
    sooner.Skiing is alright,but 60 ponies isn't world class and if
    we can improve it easily with this device.... So if anyone has one
    or knows someone who has one and could give me some feedback about
    it,maybe it's worth the 50-60 bucks to get one.
    
    
    Thanks in advance,
    Keith G.
    

    	I have one of those Hydrofoil GT on my 16' Steury runabout powered
    by a 55hp Johnson,and it did help getting the bow down and the boat
    on a plane faster.Handlind seems to be better but it seems I lost
    a couple mph at the top end.So to me the Hydrofoil GT was worth
    it.
    
    Now for the price,I only paid $29.95 for it. This guy Paul Hojlo
    from the Fishing note file contacted the company that makes/sales
    these Hydrofoil GT's and told him he could have them at this price
    if he sold/bought a certain number of them.They are well worth the
    $29.95 price. In my case I don't think that I would have spent the
    $60.00 on them.
    
    In any case you can contact the company directly or check the fishing
    note file (rainbow::fishing) for the note (I don't know the exact number)
    and contact Paul for some details on what he did.
    
    
    
    
    Hopes this help
    Frenchy

	Hi gang,.

		I am wondering about these hydrofoils that can be attached 
	to the cav plates on lower units. I just bought one (cause I got a good
	price on it) Its a STING RAY (one piece as apposed to the DOEL fin 
	which is 2 pieces.)

	My boat will porpoise when I trim it off for maximum engine performance/
	speed. I have kicked the motor down 1 notch and fixed the problem but
	feel significant degradation at top end speed. 

	I am told that if I install this foil, I can kick out the engine back 
	to where I get max speed out of it. (In this position, it also takes
	longer to plane off with a skier behind me) The statement I'd like 
	some input on is, if I install this foil and kick the motor out, I 
	am told that it will accentuate the porpoising. Is this true? I am also
	told I will improve ;^) gas consumption with less strain on the engine
	Is this also true? and lastly, I am told that I will 'hop out of the
	hole' quicker? Is this true too?

	Any thoughts out there? I'd really like to hear from you guys/gals!

	Eagerly_awaiting_your_opinions_and_experience!  
	
	Thanks!  Roger (mr. moderator, I have done a search on this and have
			 not found any answers to my particular questions
			 A referal to another note is greatly appreciated
			 if appropriate)

    
    
    See note 173.

	Thanks for the pointer!!!! How the %^&* did I miss it? (brain dead 
	today... thinking about getting my butt on the water I guess) From 
	what everyone says, I guess I will install it today! Skiing at lunch
	anyone?? I'll be there!

	Roger

    
      Doel-Fin type wings will NOT usually increase your top-end at
    all. The only exception is if the boat is underpowered, then the
    fin helps get the boat up on a slightly higher plane - which with
    the reduced drag (because less of the boat is in the water) will
    help to increase your top end.
    
      Your lowering of the motor to stop the porposing is not the
    real answer; what it *did* was cause more drag at the back of the
    boat. The *real* answer to your porposing is to get more weight
    to the front of the boat. Sometimes, just 20 lbs. or so is enough
    to stop the porposing. I don't know if the fin will help, I kind
    of doubt it. It MOST definitely will get you on plane faster.
    
       For skiing, you should have the motor trimmed all or almost all
    of the way down. This helps the boat get on plane faster which is
    what you want for skiing. Unless your boat has marginal speed for
    skiing, you should NOT be concerned about top-end for skiing.
    
      *IF* your motor is moved as high as practical for top-end, the
    fin WON'T even be *IN* the water at top speed with the motor trimmed
    out! (and you wouldn't normally want it to be anyway - it would
    just be more drag and slow you down.
    
    				Hope this helps,
    					Kenny

	Well folks,
	
	I thought I would poke this one more time to let you know how I made 
out with the Hydrofoil. First, Thanks for the input (most of which already 
existed in note #173. (thanks for the pointer!)

	I put the foil on last night and it makes a significant difference 
in planing off early. (I was planing off in ~8-9 seconds, now its ~3 seconds.)
The engine seems to work as hard getting out of the hole but for a much less
amount of time. I kicked the engine out 1 notch from the transom which also
decreases the 'hard work' the engine does at top end. I did loose about 3 miles 
per hour, but it does not matter 'cause its faster than I need to go when 
pulling a skier. (28-32 mph)  

	I may be pushing it but Sting ray also has small keels that can be 
attached to the underside of the fin which they claim is like power assisted 
steering. Anyone use these as well?  Like I said, Maybe I should leave well 
enough alone   8^)


Now for a towbar ! 

I have seen one made by eze-swim which is a removable unit and mounts to a plate
screwed to the floor. ($130.00) with braces that attach to the ?couling? around
the engine. (not sure what its formally called, the area with drain holes where 
all the cables and gas line sit) What I would really like is one that mounts
to the top of this ?couling? (no, this is not an aircraft 8^) which the true
definition of couling applies too)  Any pointers out there? I have not seen it
in any mag. but am sure they are out there. Whats a good price? 

a devout boats 'noter'   ;^)_Roger_

    I AM WONDERING IF ANY ONE COULD GIVE ME TEL. NUMBER OF A SUPPLIER
    OF DOEL FINS IN MASS. AREA ,ALSO WHAT IS AVG. PRICE? ALTERNATIVELY
    DOES ANYONE HAVE ONE FOR SALE?
    REGARDS 
    WILLIE SHAW
    7822 3344
    

    I've seen 'Stingrays' (similar to Doel fins but one piece instead of
    two) advertised in the Overton's catalog for $60.  I believe Doel Fins
    are in the $40-$50 dollar range.  I stumbled across a Stingray at Spags
    last week for $44 dollars and scooped it up !  Its not on the boat yet,
    maybe this weekend.
    
    Denise
    

Hmmm - I'm intrigued.  For years now, we've been using a friend's 15' 
"plain-old" aluminum runabout with a 40HP Johnson for tubing and zip-sledding
(like tubing, except on a piece of plywood!).  The motor is obviously too
small for skiing.  Anyway, we've grown in years and in poundage and I was 
wondering if this device would be "uplifting" (sorry, couldn't resist) for
an old and tired Johnson.  We sometimes have people hanging over the windshield
to help get the boat on a plane!


/C

Dolefins are available over the counter in lots of places, two of the largest
in Mass are Boat/U.S. in Waltham (617-899-2000) and Bliss Marine in Dedham
(617-329-2430) and Woburn (617-933-3290). 

The price is $50 at Boat/U.S., but you must be a member ($17/year unless you
are a member of an group like the U.S. Power Squadrons through which you can
get a discount, or if you find the $12.50 reduced rate coupon/offer). Don't
remember the price at Bliss, $60 comes to mind.

john

From what I remember on the back of the Dolefin package the range of application
is wide indeed. 40 HP motors were well within the range. There aren't many sizes
to select from, but check the chart just to make sure you have one that fits the
size motor you have. (This is probably one reason why the Dolefin is made in two
pieces instead of one - one size fits most.)

john

    Just bought a Doel at Bliss, for 49.99 +tax (5%). 
    
    Mike

    Just put a Doel Fin on last week ($49.95 seems to be the current
    standard cost, down about $20 from last year).  Only had it out once to
    test it and do a little fishing.
    
    Put the fin on a 19' Invader, 305 MERcruiser, Alpha ONE outdrive.  Used
    to come up on plane at about 2200 RPM (very little variance due to
    load, 1 person of 5 always around the same speed) and able to hold down
    to about 2000 RPM and 20 MPH.  Can now come up at around 1900-2000 RPM
    and hold to about 17 MPH and 1800 RPM.  Didn't get a chance to check
    out top end, left it was rainy and breezy, fished for four hours and it
    was almost dark.  Bow did not come up as high when coming out of the
    hole, probably 3-5 degrees less (just a guess, nothing scientific about
    it) and in about 1/2-2/3 of the time (no power shots out of the hole,
    just bringing it up easily).  Noticed a slight handling difference on
    plane below 30 mph.  Still probably enough water around/under the fin
    for it to have an effect.  Above 30, no noticable affect, probably not
    enough water around it (hard to tell when your in the cockpit).  I am
    not worried too much about any top end drop off.  I top out at around
    50-57 (this does depend on load) and generally don't spend too much
    time above 40 (fuel efficiency drops considerably after that).  Haven't
    had it long enough to see what fuel savings, if any are realized. 
    Keeping the bow down below planing speed, getting on plane quicker and
    at lower RPM and holding at a lower speed were worth the cost of the
    fin to me.
    
    Mike S.
     

    Overton's offers two different hydrofoil stabilizers, the Sting Ray
    for $59.95 and the Whale Tail XL for $49.95.  The Sting Ray looks
    sharper, but the Whale Tail is larger and looks like it might provide
    greater stabilization.  Sting Ray also recommends the use of a 
    Torque Equalizer or torque wedge, which appears to be a fin installed 
    on the starboard side of the Stabilizer.
    
    Any information on one brand versus another or the need for the Torque 
    Wedge would be appreciated.
    
    Anne

    I have a stingray on my 80 hp Merc and I think it's pretty slick.  With
    the help of power trim, I can really get my boat out of the water.  I
    don't seem to be drfting much water at all.  6" maybe?  not bad for a
    fishing boat.  I'm also not making much wake at top speed of 40 mph.
    
    I couldn't live without it now.
    
    As for those torque stabilizers, I think you're supposed to put them on
    in pairs.  On the underside of the fin, there are pre-drilled holes for
    them on both sides along with little lines to indicate the angle that
    you apply them at.
    
    I've never seen the need for them and I've never seen them on other
    people's boats with stingray fins.  What are they supposed to do,
    anyway?
    
    If I hang enough stuff off the transom, sooner or later I'll look like
    the Australia II!
    
    :-) :-) :-)
    
    /brett 

    I was able to do a side-by-side comparison as well as a before and
    after of the Doel Fin. The Stingray looked sharper because its a
    one piece fin but it's application was rather limited. Doel fin
    fits about everything, 25-335 hp, MERC, OMC, and V/P. Plus Doel
    fin comes in black (for Merc's ?) and grey (for OMC ?).
    
    My boat is a 1986 Baja 190 SunSport bowrider with a 260 Mercruiser.
    Without the Doel fin, and 3 people sitting behind the windshield
    ( not in the bow ) time to plane took a little longer than I felt
    comfortable with. The bow was up and visibilty was terrible. Installed
    a Doel fin, same prop (alum), same seating, and planing time was about
    half of what it use to be and the bow rise wasn't as great. The trim
    is a lot more responsive now too, going up or down. As part of our
    demo ride the guy took us for a ride in his own personal which was
    identical except for Doel fin (and a SS prop which helped a little
    too). His boat planed in half the time of the one we were looking at, 
    trim was very responsive as well. I'm a beleiver.  Can't comment on top
    speed loss or gain as we've only had the boat for a week now. I
    wanted it mainly for reducing the time to plane, and it did.
    
    ~jeff                
    

    
       I don't know about any one else out there but the StingRay	
    hydrofoil is great. I don't know I've waited so long to get
    one. It one piece so the force that lifts is distributed across
    more area then that of the Doel Fin. My wife and I have a 	
    Larson Senza 165 with a Evinrude 110 that will now pop up skiiers
    in the 175 to 200 lbs range with no problem. My wife is getting
    up with 1/4 to 1/3 trottle. Geez I think I'm starting to sport
    a woodie....
    
               Tom

     Doel-Fins have come way down in price this year. Last year the
    best price I ever saw was around $59; this year I have seen the
    Doel Fin for $39 with an accompanying remark about the price reduction
    (But I don't remember who had them for that price :^(  ).
    
    				Kenny

    
    They definately work....I picked mine up at Forest Marine
    for $50.  
    
    jd/
    

    Boat/US had a sale at the $39.95 price. Regular price there is $49.95.
    
    I still can't decide if my boat works any better with the Doel Fin. It
    has been too long since I took it out last (September) and I put it on
    this year before I put it in the water. One thing, the boat porpises on
    flat water and that is something I don't remember it doing before and
    something that the Dole Fin is supposed to help eliminate. The other
    variable is the hull, the repairs to the hull may be the source of this
    problem but again its been so long since I was out in last it is hard
    to remember exactly what it was like. I think that if I can I will get
    the Dole Fin off and try it with out it.
    
    john

    i wish we had the same prices i just ordered one
    and here they cost $140 for the stingray
    
    reg
    

    well i fitted one (stingray) i really did notice a difference.
    i was able to take out the wedges on the motor.
    the only trouble was i bent the cavitation plate so i had to have 
    some extra aluminium plates welded on top of the cav plate.
    after doing this however there seems to be approx 50% improvement
    pulling one skier out and approx 20-30% improvement pulling up two.
    i also found that the top end did not change at all .
    reg

    My 15' Lyman with 50HP Yamaha would start to "porpoise" when I hit
    5,000 RPM. (As I understand the definition of the term, the bow would
    start to rise up and slap down with increasing frequency so that I
    would not continue to run at 5,000 for more than a few seconds.)
    
    I installed the Doel fins and the problem has disappeared AND the ride
    is smoother while cruising in the mid-4,000 RPM range (about 20MPH) AND
    the bow stays lower at slower speeds.
    
    I'm a satisfied buyer!
    
    Ben Day

    I don't have a doel fin but I did install a trolling plate on
    my 25hp Merc. and my 88hp Johnson. The plate (in the "up" position)
    works very much the same as a doel fin. 
    
    There is a dramatic difference in getting the boat on plane. Why
    don't the manufacturers (of motors) build a dole fin type of set up
    into the lower unit of every motor....any bites?
    
                                        Jeff (Captain)
                                        Team Starcraft

    After reading all the comments about these I have decided to intall
    one on my ski boat (16 1/2 Ft J Craft with 150HP Johnson V6)
    It sounds like just the ticket to make the boat behave since it
    tend to propoise a bit. It should also help to get boat up on plane
    faster with a skier out back. I purchased one of the Sting Ray 
    models up here in Canada when they wen't on sale for $59 (regular $83)
    which I can't beat even through US mailorder.
    

    I'm having a problem and I'm wondering if anyone has any ideas -
    
    I have a 1990 Stingray 17.5' with a 175HP Mercruiser (I've had other
    notes in here about the Merc experiences). Last year, the boat seemed
    to ride high in the bow out of the hole and getting skiers up, while
    not difficult, certainly was not as good as a friend's 16' with 90HP
    OB( yes, I know about IO vs OB performance). Thought a doel fin might 
    help so I got one this year.
    
    Initial experience was positive, the bow didn't come up near as much
    and getting skiers out of the water was a breeze. However, the boat did not
    seem to handle near as well as it had previously (never even felt
    comfortable opening it up to check out top end) and we had two incidents 
    skiing where the bow almost went under during an easy turn (both times 
    with passengers up front if that matters). First time, I was the skier 
    and thought maybe the driver did something foolish, second time, I was the
    driver and didn't think I was being foolish. Obviously, the possibility 
    of swamping is of concern to me.
    
    Finally, after the second incident of almost becoming a U-Boat commander,
    I removed the doel fin and now the boat is back to its superb handling 
    with a full sky view as you start out of the hole.
    
    My questions:
    
    Any ideas what causing this and what could be done to fix it? Are there
    some boats that just shouldn't have doel fins? Would this be related
    to hull design?, engine configuration?, both?
    
    The marina where I bought the boat/fin told me up front I shouldn't
    need any help with a 175HP but I bought it anyway. Now they say "we
    told you so" and suggested that I correct the "problem" with a lower
    pitch prop. Is this a reasonable suggestion/alternative?
    
    Thanks,
    
    Bill       

    
    	My neighbor had the same problem. The boat didn't handle as well at
    	50 miles per hour, it also started to bend the cavatation plate.
    	Remember that the doel is is going to act like a wing and raise the
    	back end of the boat to reach a plane faster, and it does this
    	fine. I feel the doel fin was not intended for the high horse I/O's
    	but more for the low horse power OB's ie 25, 50 and so on. The doel
    	fin is going to change how the boat handles, so if the boat is
    	going 50 mph, it is going to reach much differently. There are some
    	other things that can be done to "get out hole" faster. Change the
    	pitch of the prop to a smaller number, the top end speed will slow
    	down some but the boat will hit a plane faster. Just be carefull
    	not to over "rev" the engine. 
    
    	Just my .02 worth 
    
    	Mike

    Try trimming the lower unit while at speed. That's a requirement for
    using the fins. The trim system also is much more sensitive/effective
    after attaching a fin. If you are in full bow-down, get that bow up
    before you sink the ship!
    
    Mike

    re last several -
    
    .39 I'm not sure I really want to start cutting away onthe fin. The
        material is a very hard rubber and I'd be concerned with too much
        vibration due to an uneven cut.
       
        Trim tabs sound interesting - what are they?
    
        Nope - no trailer yet, still looking.
    
    .40 That's exactly the opinion of the marina I go to. Both owner and
        head mechanic insist that doel fins are for "underpowered" boats
        that need some help. Their suggestion is to get rid of the fin and
        go with a lower pitch prop. They also talked about the loss of
        speed at the top end and that I would have to watch the tach
        closely.
    
    .41 Interesting comment on trimming the lower unit..... I have no idea
        what my friend was doing when he almost lost it but in my case we
        had just started up and I was banking a turn to allow the skier
        to go back and drop a ski. I had not yet finished trimming up when
        the bow started to make like a mackerel. To be honest, I've been
        reluctant to open the boat all the way up (top end is around 55MPH)
        ever since I got the fin since the handling seems so poor
        compared to before but I wasn't making adjustments to how I
        normally trim the boat either. 
    
    I'm not ready for a new prop yet - I still haven't broken the one I
    got last year ;^) I think what I'll do is put the fin back on and
    play around with trimming the engine up quicker. If it works and I
    like the feel, I'll probably keep the fin for the remainder of the
    year and consider a new prop for XMAS.
    
    Thanks for the idea! I'll let you know how it works out.
    
    Bill

    Any recent (revised?) opinions on these gadgets? They now sell for under
    $30 and the last note on experience is '91.

    Is anyone familiar with the hydrofoil offered by Cobra Marine, not to
    be confused with the OMC stern drive?  It is  a one piece stainless steel
    plate that mounts to the bottom of the cavitation plate. The company
    claims that is solves both the problem of broken and bent cavitation
    plates and the loss of top end speed.
              

    	I bought a DOEL-FIN for my 130 Mercruiser pushing an 18 ft Bayliner
    and it is the best $29.95 I ever spent.    Almost no bow lift with a
    full throttle start and on plane extremely fast.   I understand that in
    E & B Catalogue they are now down to $24.95.    I can recommend them
    fully.
    		Art

    Hi All any comments about putting a Sting ray Hydro foil on 
    my 1993 18ft freedrom 4 winns Boat with a OB 90 horse Johnson
    Motor Pro, and Cons,,, 1st I don't want to drill a hole in the
    round circle that has a little fin coming down.. I,m not sure
    whats it called it right above thr prop.... But I would like
    to get my Boat to Plane down faster....
    
    Thanks
     Mike

    I have a 17 foot Boston Whaler with 90 hp Evinrude.  I had very poor 
    results.  I saw very little help on bow lift on pulling skiers at
    start up and on moderate turns the motor would start cavitating so 
    much that I would have to slow to 10mph to clear the cavitation out.
    
    	I then removed it and gave it to a neighbor with a 17' 4 Winns with
    140 i/o and he has had moderate improvement but not great, also he does
    not have the cavitation problems I had with the outboard. 

	How do you spell it???  Whatever, I have had mixed results with one
	on a 15' Whaler w/70hp Johnson.  It brought my planing speed from
	~18-19mph down to ~12-14mph.  The boat already planed out instantly
	without the fin so there wasn't a noticable change there.  I know,
	planing at lower speed -should- happen sooner...  But, there is also
	enough drag to pull my top speed (no fin, light load) from a previous
	58-60mph down to 48-50mph.  I don't care about the speed loss (well,
	maybe a little!) because I was after lower planing speed, period.

	There are a few aluminum and even stainless steel plates on the market
	now.  They may not cause so much drag/loss of speed.

					Your mileage may vary...
						B.C.