Doel-Fin and Others??

Doel-Fin and Others??

Post by Mark W. Poo » Tue, 01 Apr 1997 04:00:00


Are any of these add-on fins superior to the others??   I'm about to
put one on a 19' Sunbird and noticed that Walmart has the large size
I/O version on sale for $25. Its not the Doel-Fin brand but it looks a
heck of a lot like them.

Also, any reasons why I SHOULD NOT use one of these??  Four years ago
I used one on a 19' boat and it worked miracles on hole-shot
performance.  I always wondered if it placed damaging stresses on the
outdrive.

thanks,

Mark.

 
 
 

Doel-Fin and Others??

Post by Doug Meredit » Tue, 01 Apr 1997 04:00:00



Quote:
> Are any of these add-on fins superior to the others??   I'm about to
> put one on a 19' Sunbird and noticed that Walmart has the large size
> I/O version on sale for $25. Its not the Doel-Fin brand but it looks a
> heck of a lot like them.

> Also, any reasons why I SHOULD NOT use one of these??  Four years ago
> I used one on a 19' boat and it worked miracles on hole-shot
> performance.  I always wondered if it placed damaging stresses on the
> outdrive.

> thanks,

> Mark.

One of the benifits of the doel fin is that it sandwichs the cav plate on
the outdrive.  Some of the others bolt on top of the cav plate, which could
cause the cav plate to break under some uses, while because of the doel fin
sandwich construction, is less likly to occur.  Also, it is my
understanding that if it does break, that doel fin will pay for the repair.
 I had one on my old Baja 208.  I saw no difference in performance.  I
guess how good they work depends on how good the hull design is on the
boat.  Better design, less benifit from the fin.  Several tests that I have
read over the years in magazines show little or no improvement by adding
the fin.  But for only $25 for all of them, if it doesn't work, you can
take it off, and repair the holes, and not be out a lot of money.

Doug

 
 
 

Doel-Fin and Others??

Post by Al Harne » Tue, 01 Apr 1997 04:00:00

Quote:

> Are any of these add-on fins superior to the others??   I'm about to
> put one on a 19' Sunbird and noticed that Walmart has the large size
> I/O version on sale for $25. Its not the Doel-Fin brand but it looks a
> heck of a lot like them.

> Also, any reasons why I SHOULD NOT use one of these??  Four years ago
> I used one on a 19' boat and it worked miracles on hole-shot
> performance.  I always wondered if it placed damaging stresses on the
> outdrive.

> thanks,

> Mark.

I tried the Wal-Mart fin and lost a couple of mph off the top.  It did
hold the bow down on a hole-shot (wonder where THAT term got started?).
I took it back and made my own out of 1/8" aluminum plate..not near as
wide but a little longer.  Cost me $15 and works great.  I have it
bolted under the anti-cav plate for strength.  
Al

 
 
 

Doel-Fin and Others??

Post by Robert Det.. » Tue, 01 Apr 1997 04:00:00


Quote:

>> Are any of these add-on fins superior to the others??   I'm about to
>> put one on a 19' Sunbird and noticed that Walmart has the large size
>> I/O version on sale for $25. Its not the Doel-Fin brand but it looks a
>> heck of a lot like them.

>> Also, any reasons why I SHOULD NOT use one of these??  Four years ago
>> I used one on a 19' boat and it worked miracles on hole-shot
>> performance.  I always wondered if it placed damaging stresses on the
>> outdrive.

>> thanks,

>> Mark.

>I tried the Wal-Mart fin and lost a couple of mph off the top.  It did
>hold the bow down on a hole-shot (wonder where THAT term got started?).
>I took it back and made my own out of 1/8" aluminum plate..not near as
>wide but a little longer.  Cost me $15 and works great.  I have it
>bolted under the anti-cav plate for strength.  
>Al

  I put a Doel-Fin on my 21 foot Dy*** bowrider and it cured my
cavitation problems, but my top end dropped from 55 to 51.  The                
boat is also pickier about the trim angle now.  I don't know if there
would be much difference between brands - but everyone I know has
lost top end with them (I believe that Doel-Fin claims to increase
top end and mileage).  The boat is also quicker to plane - but if you
try to run at 18mph to pull a scurfer, then the reaction of going on
and off of plane is more dramatic than before.

advantages:
1) Quicker to plane (it helps to pull up skiers)
2) Less likely to cavitate on full throttle starts and sharp turns

disadvantages:
1) You have to be more precise with the trim
2) You lose top end
3) The point where you plane and come back off of plane is more distinct,
    the difference is more sudden.  This is only a problem if you're trying
    to cruise near to that point.

  I much prefer having the Doel-Fin to having the cavitation problems, so
I'll stick with mine.

Robert

 
 
 

Doel-Fin and Others??

Post by Fu » Tue, 01 Apr 1997 04:00:00

Quote:

> Are any of these add-on fins superior to the others??   I'm about to
> put one on a 19' Sunbird and noticed that Walmart has the large size
> I/O version on sale for $25. Its not the Doel-Fin brand but it looks a
> heck of a lot like them.

> Also, any reasons why I SHOULD NOT use one of these??  Four years ago
> I used one on a 19' boat and it worked miracles on hole-shot
> performance.  I always wondered if it placed damaging stresses on the
> outdrive.

> thanks,

> Mark.

There is no reason why you should not buy one. If you are looking better
performance I would certainly recommend it. The Doel-Fin is the most
popular around here. I sold different styles retail for years and very
few customers had anything negative to say about them. Stick with the
name brand Doel-Fin has excellent customer relations too.
 
 
 

Doel-Fin and Others??

Post by Sealegs9 » Wed, 02 Apr 1997 04:00:00

Wallmart carries the stingray model thats what i put on my 22ft boat works
great

 
 
 

Doel-Fin and Others??

Post by acssys.. » Wed, 02 Apr 1997 04:00:00

Quote:

> One of the benifits of the doel fin is that it sandwichs the cav plate on
> the outdrive.  Some of the others bolt on top of the cav plate, which could
> cause the cav plate to break under some uses, while because of the doel fin

There could be some difference between one piece fins and 2 piece fins
as well...

Quote:
> sandwich construction, is less likly to occur.  Also, it is my
> understanding that if it does break, that doel fin will pay for the repair.
>  I had one on my old Baja 208.  I saw no difference in performance.  I
> guess how good they work depends on how good the hull design is on the
> boat.  Better design, less benifit from the fin.  Several tests that I have
> read over the years in magazines show little or no improvement by adding
> the fin.  But for only $25 for all of them, if it doesn't work, you can
> take it off, and repair the holes, and not be out a lot of money.

I have seen it make the most difference on smallish boats that are high
powered. Some of them wanted to fly out of the water without the
Stingray and were hard, if not dangerous, to drive. With the fin on they
were much more manageable. One boat in paricular had what I would
consider a marginal hull design. It was a mid 80's Checkmate
17' diplomat - 185 hp V6 i/o. This hull didn't turn well at all.


 
 
 

Doel-Fin and Others??

Post by And » Thu, 03 Apr 1997 04:00:00

Quote:

>Wallmart carries the stingray model thats what i put on my 22ft boat works
>great

I WOULD AVOID the DOEL FIN and any other bolt-on wonder-skeg. I had one on a
17' Formula with 115 hp Johnson for a couple years and thought it was pretty
good, until I removed it to see how the boat handled without it!

My experience WITH Doel Fin:
1) slower speed
2) sluggish handling
3) dangerous sliding in corners
4) no difference in time to plane
5) basically a big drag, literally

Same boat WITHOUT Doel Fin:
1) Faster
2) Handled much better
3) responsive
4) more fun to drive
5) felt like a new boat

If all those Doel Fins and Sting Rays are so good, why don't the outboards and
sterndrives have them designed in? Answer: Because they don't provide any
measurable advantages, and create a lot of DRAG. As long as you have power
trim on your boat, skip the Doel Fin.

Captain Andy

 
 
 

Doel-Fin and Others??

Post by J » Thu, 03 Apr 1997 04:00:00

Quote:


>>Wallmart carries the stingray model thats what i put on my 22ft boat works
>>great

>I WOULD AVOID the DOEL FIN and any other bolt-on wonder-skeg. I had one on a
>17' Formula with 115 hp Johnson for a couple years and thought it was pretty
>good, until I removed it to see how the boat handled without it!

>My experience WITH Doel Fin:
>1) slower speed
>2) sluggish handling
>3) dangerous sliding in corners
>4) no difference in time to plane
>5) basically a big drag, literally

>Same boat WITHOUT Doel Fin:
>1) Faster
>2) Handled much better
>3) responsive
>4) more fun to drive
>5) felt like a new boat

>If all those Doel Fins and Sting Rays are so good, why don't the outboards and
>sterndrives have them designed in? Answer: Because they don't provide any
>measurable advantages, and create a lot of DRAG. As long as you have power
>trim on your boat, skip the Doel Fin.

>Captain Andy

you forgot one VERY IMPORTANT thing
doel fiins ,sting rays or any other
cavition plate bolt on, WEAKENS the
cavitation plate and WILL eventualy
BREAK the cavitation plate!!!!!!
THEY ARE GARBAGE!!!
and they cause more damage than good!!!
 
 
 

Doel-Fin and Others??

Post by Fu » Thu, 03 Apr 1997 04:00:00

Quote:



> >>Wallmart carries the stingray model thats what i put on my 22ft boat works
> >>great

> >I WOULD AVOID the DOEL FIN and any other bolt-on wonder-skeg. I had one on a
> >17' Formula with 115 hp Johnson for a couple years and thought it was pretty
> >good, until I removed it to see how the boat handled without it!

> >My experience WITH Doel Fin:
> >1) slower speed
> >2) sluggish handling
> >3) dangerous sliding in corners
> >4) no difference in time to plane
> >5) basically a big drag, literally

> >Same boat WITHOUT Doel Fin:
> >1) Faster
> >2) Handled much better
> >3) responsive
> >4) more fun to drive
> >5) felt like a new boat

> >If all those Doel Fins and Sting Rays are so good, why don't the outboards and
> >sterndrives have them designed in? Answer: Because they don't provide any
> >measurable advantages, and create a lot of DRAG. As long as you have power
> >trim on your boat, skip the Doel Fin.

> >Captain Andy
> you forgot one VERY IMPORTANT thing
> doel fiins ,sting rays or any other
> cavition plate bolt on, WEAKENS the
> cavitation plate and WILL eventualy
> BREAK the cavitation plate!!!!!!
> THEY ARE GARBAGE!!!
> and they cause more damage than good!!!

I'm curious, where do you get your information? Can you support this
or is it guesswork!
 
 
 

Doel-Fin and Others??

Post by Fu » Thu, 03 Apr 1997 04:00:00

Quote:


> >Wallmart carries the stingray model thats what i put on my 22ft boat works
> >great

> I WOULD AVOID the DOEL FIN and any other bolt-on wonder-skeg. I had one on a
> 17' Formula with 115 hp Johnson for a couple years and thought it was pretty
> good, until I removed it to see how the boat handled without it!

> My experience WITH Doel Fin:
> 1) slower speed
> 2) sluggish handling
> 3) dangerous sliding in corners
> 4) no difference in time to plane
> 5) basically a big drag, literally

> Same boat WITHOUT Doel Fin:
> 1) Faster
> 2) Handled much better
> 3) responsive
> 4) more fun to drive
> 5) felt like a new boat

> If all those Doel Fins and Sting Rays are so good, why don't the outboards and
> sterndrives have them designed in? Answer: Because they don't provide any
> measurable advantages, and create a lot of DRAG. As long as you have power
> trim on your boat, skip the Doel Fin.

> Captain Andy

Hey captain, if you were building a piece of power equipment would you
build in a feature which indicates it is not enough power. I have to
disagree that hydrofoils are no good.  Whoever installed the one on your
motor must have been looking for increased performance. Doesn't logic
dictate that if the boat performed worse with it on the operator would
remove it?  With many years in this industry, I have seen hundreds of
people install them with positive results and very few broken
anti-ventilation plates.
 
 
 

Doel-Fin and Others??

Post by Critterdo » Thu, 03 Apr 1997 04:00:00

Quote:




> > >>Wallmart carries the stingray model thats what i put on my 22ft boat works
> > >>great

> > >I WOULD AVOID the DOEL FIN and any other bolt-on wonder-skeg. I had one on a
> > >17' Formula with 115 hp Johnson for a couple years and thought it was pretty
> > >good, until I removed it to see how the boat handled without it!

> > >My experience WITH Doel Fin:
> > >1) slower speed
> > >2) sluggish handling
> > >3) dangerous sliding in corners
> > >4) no difference in time to plane
> > >5) basically a big drag, literally

> > >Same boat WITHOUT Doel Fin:
> > >1) Faster
> > >2) Handled much better
> > >3) responsive
> > >4) more fun to drive
> > >5) felt like a new boat

> > >If all those Doel Fins and Sting Rays are so good, why don't the outboards and
> > >sterndrives have them designed in? Answer: Because they don't provide any
> > >measurable advantages, and create a lot of DRAG. As long as you have power
> > >trim on your boat, skip the Doel Fin.

> > >Captain Andy
> > you forgot one VERY IMPORTANT thing
> > doel fiins ,sting rays or any other
> > cavition plate bolt on, WEAKENS the
> > cavitation plate and WILL eventualy
> > BREAK the cavitation plate!!!!!!
> > THEY ARE GARBAGE!!!
> > and they cause more damage than good!!!

> I'm curious, where do you get your information? Can you support this
> or is it guesswork!

I agree that fins will weaken/stress the anti-vent plate, but don't
think it accurate to state with certainty that they "will eventually
break the plate". In some boats they can be helpful, in some boats they
can actually degrade performance. I would not agree that they are
garbage, but do feel that they are a less expensive and less functional
alternative to real trim tabs...which can be a *hugh asset* in many many
boats.

I have no doubt that fins have contributed to failure of the
anti-ventilation plate on some engines, but suspect that such failure is
not really common. However, if its my boat, 1/Ks is too much.

My only "support" of the fact that failures can occur is to share my
dealers experience of having seen a number of plates fail over a period
of years, and word-of-mouth opinion of several *knowledgable* boat
operators that state their reluctance/refusal to use them because they
know of cases wherein fins have contributed to plate failure.

--
Michael

 
 
 

Doel-Fin and Others??

Post by Louis B. Bryd » Thu, 03 Apr 1997 04:00:00

Sort of depends on what you're looking for, and what your application is.
Maybe they don't work as well on larger boats/engines, but on my Boston
Whaler with a 9.9 Honda, the Dolfin helped ALOT in getting to a plane, and
stopped the 'porposing'.  Also allows me to stay on plane at a much lower
speed, with less wake.  Probably did reduce the top speed a little, but I
overall I think it improved the stability and handling.  Mine is the one
peice 'wrap around' Dolfin, so I think this distributes the load to the
motor plate as compared to the two part bolt on versions (sting ray?).
Mine is 'retained' with a couple of small screws, but they don't really
see much load because the fin is restrain in all but one DOF by the molded
geometry.

Best $30 I've spent on the boat.

My $0.02

--
Louis B. Brydon

WA6OCZ
SEASTAR - Redwood City, Ca, Ba, USA, Terra, Sol, Milkyway
O-

 
 
 

Doel-Fin and Others??

Post by J » Fri, 04 Apr 1997 04:00:00

On Wed, 02 Apr 1997 13:46:36 -0500, Critterdoc

Quote:

>I agree that fins will weaken/stress the anti-vent plate, but don't
>think it accurate to state with certainty that they "will eventually
>break the plate". In some boats they can be helpful, in some boats they
>can actually degrade performance. I would not agree that they are
>garbage, but do feel that they are a less expensive and less functional
>alternative to real trim tabs...which can be a *hugh asset* in many many
>boats.

>I have no doubt that fins have contributed to failure of the
>anti-ventilation plate on some engines, but suspect that such failure is
>not really common. However, if its my boat, 1/Ks is too much.

>My only "support" of the fact that failures can occur is to share my
>dealers experience of having seen a number of plates fail over a period
>of years, and word-of-mouth opinion of several *knowledgable* boat
>operators that state their reluctance/refusal to use them because they
>know of cases wherein fins have contributed to plate failure.

>--
>Michael

as for me i also work in the industry as a mobile tech
so i get to see a lot of difernt yards and boats
my experiance is that these fins when time and corrosion
take there toll usualy snap the plate .
also where i see this the most is on the yamahas first and then the
johnsons , whith the johnsons i usualy see a lot of degradation in the
lower case ,but the yamahas for some reason i don't see this, i think
they may just be weaker thinner in general in the ant- cavition plate
area .

Also common sense stands to reason a little here, all these fins do
is lift the transom  of the boat by defelting the water downward .
think about the force generated by this technique that is all directed
at the anti cavition plate.[what are we talking here a peice of cast
alluminum 1/4 inch thick if your lucky b-4 corosiion. ]

BTW my experience is in sal***er [atlantic ocean]where the corosion
pocess is a lot faster
I should have said this in the begining  sorry all !!!

 
 
 

Doel-Fin and Others??

Post by ron die » Fri, 04 Apr 1997 04:00:00

Why doesn't MC make a larger cavitation plate if it improves
performance without any problems?  They would benefit from this
wouldn't they?  Just wondering out loud!!!

I'll probably get one too---we need that quicker hole shot.  Ive been
looking at the SE Sport 300.

Ron

Quote:

>Are any of these add-on fins superior to the others??   I'm about to
>put one on a 19' Sunbird and noticed that Walmart has the large size
>I/O version on sale for $25. Its not the Doel-Fin brand but it looks a
>heck of a lot like them.

>Also, any reasons why I SHOULD NOT use one of these??  Four years ago
>I used one on a 19' boat and it worked miracles on hole-shot
>performance.  I always wondered if it placed damaging stresses on the
>outdrive.

>thanks,

>Mark.

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