Newbie: What is a doel-fin?

Newbie: What is a doel-fin?

Post by BAS T » Wed, 05 Apr 2000 04:00:00


Can someone breifly explain the purpose of a doel fin and where it is located.
Thanks in advance.
 
 
 

Newbie: What is a doel-fin?

Post by defaul » Wed, 05 Apr 2000 04:00:00

This is a $5 bill with Dole's face on it.  They just misspelled it.  ;;-)

Actually it's a fin similar to a Dolphin's tail fin that is mounted on the
outdrive in a trailing position and above the prop.   It is there to push up on
the outdrive thus pushing the bow down, to help you get on plane from the hole
shot.  It's particulary useful when pulling skiers.

Wes
In the Pacific Northwet

Quote:

> Can someone breifly explain the purpose of a doel fin and where it is located.
> Thanks in advance.


 
 
 

Newbie: What is a doel-fin?

Post by Charles Boye » Wed, 05 Apr 2000 04:00:00

Yes, you can get one at Marine West or Overton's.  It made a real difference
with my old Glasstream four banger (albeit a 3.7 liter Merc).

Quote:
> Actually it's a fin similar to a Dolphin's tail fin that is mounted on the
> outdrive in a trailing position and above the prop.   It is there to push
up on
> the outdrive thus pushing the bow down, to help you get on plane from the
hole
> shot.  It's particulary useful when pulling skiers.

> Wes
> In the Pacific Northwet


> > Can someone breifly explain the purpose of a doel fin and where it is
located.
> > Thanks in advance.


 
 
 

Newbie: What is a doel-fin?

Post by Jerry Hah » Wed, 05 Apr 2000 04:00:00

A friend has one on his boat and broke the cavitation plate at both rear
corners where it mounts.
Jerry

--
You can lead me to the water, but not away from it.

Quote:
> Can someone breifly explain the purpose of a doel fin and where it is
located.
> Thanks in advance.

 
 
 

Newbie: What is a doel-fin?

Post by Jerry Hah » Wed, 05 Apr 2000 04:00:00

The fin, I think it is the Hydro Foil, came on the boat when he bought it
approx. 4 yrs ago. As far as being loose, can't say other than it didn't
move when boat was washed, didn't actually ever use a wrench on it he has
said. Personally they way I see it is that the fin creates lift which lifts
on the 4 bolts which in turn lifts on the cav. plate only at the 4 mounting
locations with the most force on the 2 rear bolts, which is where it broke.
It would seem the best design would mount under the plate thus applying lift
to the whole plate, unfortunately there is no prop clearance there. BTW,
since he does have a swim platform and ladder, it was not stepped on. Since
he has bought another boat and welded this one back together w/o fin, it is
of no longer a concern. I'm sure there are many without broken plates using
the fins, and some with.

Regards,
 Jerry

--
You can lead me to the water, but not away from it.

Quote:
> if your buddy had secured the dolefin properly and kept the bolts tight,
it
> would not have broken his cav plate. however, a loose dolefin flopping on
the
> plate will surely break it, as will a dolefin that is bolted on the very
end of
> the plate.

 
 
 

Newbie: What is a doel-fin?

Post by Dave Brow » Wed, 05 Apr 2000 04:00:00

Quote:

> if your buddy had secured the dolefin properly and kept the bolts tight, it
> would not have broken his cav plate. however, a loose dolefin flopping on the
> plate will surely break it, as will a dolefin that is bolted on the very end of
> the plate.

Untrue -- even a properly mounted Doel Fin will break a cavitation plate of an
engine whose plate was thin to begin with. When you think about it, the
anti-ventilation plate (the proper name for it) is designed with a thickness in
mind that does not include attaching an air foil to it. There's gonna be some
breakage on some applications for that reason alone.

Personally, for every boat they've helped, I can show you an equal number that
performance was degraded significantly or even made dangerous with a fin
attached.

Bottom line -- if they work in every application, the manufacturer would bolt
them on for you.

--
Regards,

          Dave Brown
          Brown's Marina
          http://www.brownsmarina.on.ca/

 
 
 

Newbie: What is a doel-fin?

Post by Butch Amm » Thu, 06 Apr 2000 04:00:00

Quote:
>Can someone breifly explain the purpose of a doel fin and where it is
>located.
>Thanks in advance.

The doel-fin is a performance hard plastic fin that screws onto the cavitation
plate on your lower unit.

They say they help get you on plane quicker and help with steering.  I've also
heard that they hinder the top end speed a bit.

There are all sorts of different models to choose from.  Go into an internet
search engine like Lycos and enter doel fin.  You'll get a bunch of links for
them.  Or check out your local marine store.  They have them there.

Butch Ammon

 
 
 

Newbie: What is a doel-fin?

Post by MPerlst2 » Thu, 06 Apr 2000 04:00:00

if your buddy had secured the dolefin properly and kept the bolts tight, it
would not have broken his cav plate. however, a loose dolefin flopping on the
plate will surely break it, as will a dolefin that is bolted on the very end of
the plate.
 
 
 

Newbie: What is a doel-fin?

Post by David S. Pendleto » Thu, 06 Apr 2000 04:00:00

Also, if you plan on buying/installing one, try to get a one-piece model.
They tend to flex less than the two-piece models.


Quote:
> >Can someone breifly explain the purpose of a doel fin and where it is
> >located.
> >Thanks in advance.

> The doel-fin is a performance hard plastic fin that screws onto the
cavitation
> plate on your lower unit.

> They say they help get you on plane quicker and help with steering.  I've
also
> heard that they hinder the top end speed a bit.

> There are all sorts of different models to choose from.  Go into an
internet
> search engine like Lycos and enter doel fin.  You'll get a bunch of links
for
> them.  Or check out your local marine store.  They have them there.

> Butch Ammon

 
 
 

Newbie: What is a doel-fin?

Post by Capt » Thu, 06 Apr 2000 04:00:00

Doel-fin and similar units are useful if your boat is (sorry) somewhat
underpowered and  a bit over weight.  Trim tabs are much more useful, although
more (a lot) expensive.  Usually the "fins" cause a minor reduction in top
speed and can cause lower unit damage.  Mercruiser won't honor a claim if the
cavation plate has been drilled or modified.
Wal Mart stocks the Doel Fin at a good price, about $30.  I had one on an old
120  I/O Mercruiser powered boat some years back and it did help off set the
weight of the after market bait tank mounted aft.
Try triming the drive, inspect the prop for damage (that has a lot to do with
performance!) and move items about to balance the hull before you start
drilling holes!
Good luck
Mike
 
 
 

Newbie: What is a doel-fin?

Post by Guy Anders » Thu, 06 Apr 2000 04:00:00

On Tue, 04 Apr 2000 23:43:25 -0400, Dave Brown

Quote:

> -- even a properly mounted Doel Fin will break a cavitation plate of an
>engine whose plate was thin to begin with.

...............................snips.............................

Quote:
>Bottom line -- if they work in every application, the manufacturer would bolt
>them on for you.

Dave--

Very sensible, and backed by a lot of experience.  But I betcha that
we will now see several posts testifying to the benefits of the fins.

:-]

Guy A
Ripley, TN

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

WORK like you don't need the money,
LOVE like you've never been hurt,
DANCE like nobody's watching!

 
 
 

Newbie: What is a doel-fin?

Post by Charles Boye » Thu, 06 Apr 2000 04:00:00

All I will say is that it DID help my old boat, and that the Alpha I had no
problems having it attached.  I wouldn't attach one to an aircraft carrier
or a rowboat, but depending on the outdrive, I'd say that it *might* be
worth a try.

Typically, when you ask qa bunch of people if any modification is a good
idea, there'll be those that will say either 'Oh yeah, the greatest thing
since the G-string!' or 'Nahhh, if you want to ruin your boat then do
that...'  And both would be right, depending on the application.  For
example, I've been thinking about adding some Bennett Trim Tabs to my Four
Winns Horison 190, and I have heard some fairly passionate arguments in both
directions from my boating friends.  Since it is a six hundred dollar
experiment (once you get the tabs, the indicators, etc. installed) I want to
hear everyone's opinion.

 If you could find someone who's done it to a similar boat to your, with the
same engine/outdrive combo, then I'd defer to their experience.  As for me,
I'm waiting until I see someone else with trim tabs on a boat just likemine
before I jump in.


Quote:
> On Tue, 04 Apr 2000 23:43:25 -0400, Dave Brown

> > -- even a properly mounted Doel Fin will break a cavitation plate of an
> >engine whose plate was thin to begin with.
> ...............................snips.............................
> >Bottom line -- if they work in every application, the manufacturer would
bolt
> >them on for you.

> Dave--

> Very sensible, and backed by a lot of experience.  But I betcha that
> we will now see several posts testifying to the benefits of the fins.

> :-]

> Guy A
> Ripley, TN

||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|||||||||||||||||||||||||||||||||||||||||||||

- Show quoted text -

Quote:

> WORK like you don't need the money,
> LOVE like you've never been hurt,
> DANCE like nobody's watching!

 
 
 

Newbie: What is a doel-fin?

Post by SXM Sail » Thu, 13 Apr 2000 04:00:00

Doel-fin is a brand name for a plastic device  added to the cavitation plate on
an outboard.  It looks like an airplane's wings when attached and acts like
them also.  It provides lift to the stern of the boat to help it plane better .
Particularly helpful on lightweight boats like inflatable dinghies because it
keeps the stern more stable and controls side-slip and cavitation. Been using

Quote:
>explain the purpose of a doel fin and where it is located.