Dolphin vs. tabs... URL for info?

[erikgreen]

Hey all -


I have a couple friends who swear by dolphin fins (whale tails) on their small boats. Does anyone have a URL reference to a web page I can point them to with good info on exactly why tabs are better, and what the negative consequences of the whale tails are?

I can give them a lot of anecdotes about what people have said here, but a web page with hard facts and good reasoning will be received better.

Erik

 

[ondarvr]

Re: Dolphin vs. tabs... URL for info?

If set up correctly they should see no negative affects, they may not help, but they shouldn't hurt either.

On an I/O there may be some issues because you can't really adjust anything.


The two products are completely different tools designed to do different things, so comparing them like most people do is a big mistake. Its sort of like comparing a hammer and a Crescent wrench, you can use the wrench as a hammer (and many people do) but it won't work well in that application.

 

[JB]

Re: Dolphin vs. tabs... URL for info?

There is no definitive research on this, Erik. Anecdotal stories and unqualified opinions are all you are going to find.

The consensus here is that Smart tabs work better than hydrofoils. The hydrofoils get more negative comments than the tabs.

I have had good results from both when properly set up, but preferred a SE Sport 300 hydrofoil on my 17' Boston Whaler because the tabs were too hard to get properly located on the transom.

 

[5150abf]

Re: Dolphin vs. tabs... URL for info?

I have run a tale on my boat the entire 8 years I have owned it and the previous owner ran it for who knows how long before that and I have not seen any negative effects.

I think the mount on the motor is is easily able to handle the extra load.

You will find people that are dead set on both sides of this, they both acheive essentially the same thing(plane fast at a lower speed and stabilize the boat) but go about it differently and neither one is right for every boat.

It is like Harley vs Honda, they are both bikes but you will NEVER get everyone to agree which is better.

 

[steelespike]

Re: Dolphin vs. tabs... URL for info?

I have had good luck with foils on small outboards 50hp and smallish I/Os 120 hp 18ft.
But both tabs and foils should be considered a last resort solution.Applied to a boat after set up as best possible.Usually if a motor is properly setup the foil may not be in the water at speed if it is in the water it reduces speed and may create handling problems.Tabs have been proven to plane with less power, stabilize ride,improve handling,stay on plane with less power,can improve top speed and minimize no wake speed wander.

 

[tashasdaddy]

Re: Dolphin vs. tabs... URL for info?

personally i like to lift my boat by the bottom of the transom. not the bottom of the motor that is bolted to the top of the transom. adding stress to the transom mount, bolts and the transom.

 

[SuzukiChopper]

Re: Dolphin vs. tabs... URL for info?

It's been a long while since I commented about this subject but when the fin vs. tabs convos started a couple years ago (the year I finished my transom, stringers and deck) I did some testing on my boat. It came with a fin and I never changed the motor height during my rebuild and the cav plate is the about the right height. I'm propped up in pitch and planing is difficult with 4 adults on board (a lower pitch would be nice), even with the fin, wasn't educated in the ways of props back when I bought my new one.

The one thing I noticed without the fin is I was getting some serious ventilation when trimming the motor up trying to get the bow out of the water so it wasn't plowing, but honestly at slower speeds where I didn't have to trim up as far the handling was superb. I did have slow speed tail wag though.

WITH the fin in place I could run faster speeds and get the bow up out of the water more which made for a nicer run on calm days. On choppy days the boat would hold its own a bit better as well. I did notice more ventilation in moderate corners at speed but I only tried once or twice. Us fisherman don't need to be doing radical maneuvers unless we're trying to avoid something though.

So in my case for the last little while the fin has helped but I did so much to my boat and made it so much lighter that I bet I could have lowered the motor to compensate for it sitting higher in the water and removed the fin. This year, after I'm done with the work I'm currently doing and a lot more weight being moved to the stern of the boat I'll be re-doing my tests and we'll see if the fin is even needed anymore.

I still think tabs are a smart investment but like ondarvr says, each one is a tool for a different purpose.

 

[Benny1963]

Re: Dolphin vs. tabs... URL for info?

tryed the doel on 175 crossflow trying to stop bow rise and porping.
maybe due to larger motor saw no gains other than being alittle squirrely side to side .installed smart tabs from nauticus after calling tech service for setup
no comps .kncked bow rise down on plane at near off idle speed and 0 porping at high speed ,best money ive spent other than jackplate and turbo t1 prop also picked up 1 mph at top and gained 100 rpm.
but i had to dial them in they give ya a angle gauge templte .i had to take a little angle out of mine becuse of my stern weight i had to run the 80 lb actuators and take a little off my tab angle to get in adjustment range
it was plowing alittle from the large actuators the angle change and adjust fixed it i then jacked it up went to taller tubo1 prop and gained a lot
smart tabs work the sx series are 119 shipped

 

[mickjetblue]

Re: Dolphin vs. tabs... URL for info?

Since you asked for a web page,

here is one that explains the benefits of a whale tail type fin:

http://www.associatedcontent.com/article/811915/howto_guide_for_boat_outboard_motor.html

here is one that explains the benefits of trim tabs:

http://www.boatus.com/boattech/trimtabs.htm

Both are positive and no criticisms are made.

I suppose if you could get opinion from somebody who had both on the same
boat and motor that you might want to put something on, that would be cool.

Otherwise, it's your call...

By the way, I take everything I see on web pages with a grain of salt,
especially if I wrote it.

 

[ondarvr]

Re: Dolphin vs. tabs... URL for info?

The link on foils had some good info, but never did discuss how to actually do any setup to get the best results (if the would help). It also used incorrect terms and was a little sketchy on some details.

 

[erikgreen]

Re: Dolphin vs. tabs... URL for info?

The one thing I'm really looking for is information on how the whale tail behaves in turns, since I've heard the most worrying information about that as compared to hull mounted tabs.

Issues of force and loading on the engine aside, the boats we use the tails on are RIBs, and they can (and do) make 180 and 360 degree turns in something like 3x their own length sometimes, and high speed turns too.

Erik

 

[ondarvr]

Re: Dolphin vs. tabs... URL for info?

Again, mounted correctly they should have little to no affect, mounted like most people do it, it would still be a case by case situation, from terrible to OK.