what do we think of doel fins?

J

jimmycc

New Member
Joined
12 May 2007
Messages
19
Visit site
I currently use my boat for waterskiing with a 21in propellor. This gives me problems when mono skiing and i thought i should change the prop to a 19in. Which would pull much better. Someone said i should fit a doelfin. So my question is this, are they any good, do ikeep my 21 propellor or change the prop as well as the doelfin. I have also seen something called a whaletail, which is similiar to the doelfin but much bigger. They say increased fuel conomy as well, but who knows. your help please.
 
Yes,

They do work! Some would say they add additional stress to the engine but I do not know. If you are skiing prop her down and add the dole fin. In that way she will pop you out a lot faster.

I never got any better economy..but it did pop out faster!

Paul /forums/images/graemlins/smile.gif
 
I don't think it'll help your particular problem much, you need better pull at low speed to get the ski out of the water. The doel fin wont have much effect until you pick up speed, by which time the resistance from the skier will be reduced anyway. Having said that, they're cheap compared to a new prop, so it may be worth trying first.
 
I used the doelfin about 12years ago on a Fletcher 16GTO and was impressed by the performance. Yes I notice better fuel range, stability and most important to me lift.

Yes I can recommend it, had it fitted to a 80hp Mercury and it was straight forward to fit.
 
I've fitted them in the past as well.
Pros.- Onto the plane quicker:stay on the plane at lower revs.
Cons.- Tend to make boat broach in a following sea.

I kept them on , on one boat and took them off on the other.
 
I used doelfins and thought they were good. It was a 17ft Shakespeare with 90HP Merc straight 6 - mmm, don't you just love those motors!! Anywasy, you can put some sharp turns in without cavitation...or more probably, ventilation. Same effect, different cause!

You don't say size of boat / engine?
 
I have the Attwood gull wing hydrofoil.fitted to a 15ft hull, best thing i ever bought, straight up on the plane, better at low speed on the plane, smoother, no probs with broaching, in fact the opposite as the acceleration is far quicker. It uses less fuel because it is not either on or off the plane, but has a more usable speed range.
 
They are awesome on the Sparkes Possie's 15 hp Yam rib combos, giving 26 kts and kick ass take off..............we all had to have em, and I must say they make a mahoosively overguned Avon 280 rib more stable in the high 'G' turns!!!! /forums/images/graemlins/laugh.gif

Jas.
 
Could you give some details on the boat and the engine,
depending on the size, you could improve acceleration / planing time with Smart Taps, automatic trim taps,
for boats from 10ft to 22ft
www.Nauticusinc.com
with these you can keep the engine trim angle in best position for maximum forward force,
the trimtaps will give the stern lift force
This was a improvement on my earlyer (smaller) boats
I have a used pair, PM if interested
cheers
Bart
 
For a small boat owner, fishing or rib the cost of a Doelfin type is (in my case 30 euros) how much would the tabs cost in comparison, would it be worth the extra?
 
I fitted one of these to an old 16ft Glastron with a 50hp engine and it was a great improvement.
Next I fitted it to a 1987 20ft Sea ray with a 185 V6 stern drive.
Low speed planing was improved but at more than 20 to 25 mph the boat would suddenly fall onto its chine which was very alarming so i removed it.
Same happened on the next boat, an 87 25ft Sea Ray.
I have not used it since.
A mechanic I used at the time reckoned that whilst the fin could improve a badly set up or low powered boat, it could spoil a well balanced boat.
 
I have no experience with the doelfin, so I can't make a comparison.
The automatic trimflaps made a big improvement on my 21ft 1300kg 210HP boat, they were only a small improvement on my 24ft, 1800kg 220HP boat.
price for a new pair is around 250euro
 
[ QUOTE ]
I have the Attwood gull wing hydrofoil.fitted to a 15ft hull, best thing i ever bought, straight up on the plane, better at low speed on the plane, smoother, no probs with broaching, in fact the opposite as the acceleration is far quicker. It uses less fuel because it is not either on or off the plane, but has a more usable speed range.

[/ QUOTE ]

I fitted the Attwood to a 19ft Wellcraft with 165hp Merc many years ago and had the same experience. Excellent!
 
All i can say,is that i fitted a pair of these fins(around £20-25 ebay) and a brand new high five propeller at the same time so its hard to say which was working best.
Now i fitted these before i ever took the boat out.Now,this boat was slightly heavier and larger than previous boats but i was very impressed with her speed overall,out the hole and turning in. Better than i was expecting.
All i can say, is get both,the fins will help to stabilise a little,but as your water skiing,then the prop is the most important item to replace where you'll see maximum change.

Get yourself a high five,best propeller around for water skiiing.Change it down a pitch or two. 19,20 or even 21 would be ok.
Just so happens i have an immaculate 20" going cheap /forums/images/graemlins/grin.gif shamless plug ! pm if interested
 
Sorry, been so busy forgot id even started this thread. My boat is a chris craft speedster, 19 ft with 5.0l V8, so about 270bhp. The boat is great, very fast, but crap when trying to pull 2 mono skiers out. I had a high five prop on my first boat, but didnt realise how good it was, so sold it with the boat. Let me know what you thin k is best, change the prop or go for doelfins i think doelfins, cos it would give me the lift but maintain the top speed.
 
Hi.

I'd go for both, that way your not thinking"i wonder if ...... would help" High fives are known for cutting in and getting you out the hole.
Now, if i'm right in thinking,as i really cant remember even though i have fins, the doel fins are attached to either side of the leg,correct. If correct,they're not expensive and you'll have lost nothing at all but gained something. High five prop is guarranted to make improvements but i'd drop a pitch if you spend a lot of time doing water sports.
 
You must log in or register to reply here.

Share this page

Top