super fin - long post

[cpubud]

I was reading about a product call [ Super fin ] on another forum that was suppose to help with low speed bow wonder. After reading a few of the reviews on the web site I was very interested, but did not want to spend the $200.00 bucks on something I was not sure about. so after making a template out of cardboard i got to work. I used 1/8 inch steel to make a double fin version .powder coated it and installed 2 anodes on it. I installed it and went for a test ride . The boat is a 2000 bayliner 2455LX with a 5.0 and a alpha1 outdrive running a 15x16 inch alum prop. right off the bat I noticed a major improvement in the way the boat manuvered around the docks with the slightest turn of the wheel and the low speed bow wonder was almost completly gone . the way the boat handled thru the no wake zone under 6 mph left me very impressed . Comming out of the no wake zone I throtted up and before I could get the trim tabs down to get on plane the boat was up on plane and moving. I WAS AMAZED . And whereas before the boat would need around 25 mph to stay on plane I was able to slow down to 21 mph before it started to fall off plane. over all I love the way my boat rides and handles now .

 

[H20Rat]

Re: super fin - long post

two things would worry me. That is going to be a fairly major hit on your efficiency and top speed. Also, because of that shape and how the swirling water coming off the prop is going to hit it, it is going to put massive stress on your anti-ventilation plate. It might not be long before you see stress cracks &/or failure.

smarttabs would be a much better idea...

 

[bowler]

Re: super fin - long post

Wow. Sounds good. Will you make me one!

 

[cpubud]

Re: super fin - long post

I dont know about stress on the anti-ventilation plate but as far as top end goes I gained a little over 1 mph gps . And no effect on rpm, and the boat has trim tabs on it, just dont have to use them as much in the down position to get on plane.

 

[Frank Acampora]

Re: super fin - long post

Very interesting!

Now you need to experiment on sweeping back the vertical fins and increasing the size of the lower horizontal fin. A little sweep back on the upper plate that bolts to the the cav plate would make it look a little less "boxy" and a little more "elegant."

Do more performance testing and post results. Waiting.

 

[pmillar]

Re: super fin - long post

Handling changes (improvement) makes sense considering you basically added a small rudder that also serves to focus the prop wash in the desired direction. At least that's my common sense take on it.

Do keep a close eye on things though.

 

[This_lil_fishy]

Re: super fin - long post

I assume that's an alpha one, got any dimensions on your sheet metal? We carry 1/4" aluminum plate...I might give that a go. Any improvement when reversing? My boat refuses to turn to the left in reverse due to prop wash...makes docking a giant PIA on a windy day.


Ian

 

[Bondo]

Re: super fin - long post

Ayuh,... That thing otta be a hoot in the weeds....
Or when changing/ servicing the prop...

 

[cpubud]

Re: super fin - long post

the top plate is 10x13 the sides are 10x8 cross brace is 2 inch.backing up was improved as, well but I did not use reverse alot . I am making a new one now out of stainless steel not as boxy looking that I will try out this weekend. and I thought about the weed issue but dont exspect to have a 24ft cruiser in the weeds that shallow.

 

[JoLin]

Re: super fin - long post

Very interesting!

Now you need to experiment on sweeping back the vertical fins and increasing the size of the lower horizontal fin. A little sweep back on the upper plate that bolts to the the cav plate would make it look a little less "boxy" and a little more "elegant."

Do more performance testing and post results. Waiting.

Who ya making it 'elegant' for... the fish?

Interesting idea and nice work, cpubud- very professional looking.

 

[This_lil_fishy]

Re: super fin - long post

I think I'll try to fab up the single fin version...as I do spend some time in the weeds. That is if I can get the chance....


Ian

 

[cpubud]

Re: super fin - long post

finished the stainless steel one and got it mounted,looks better. now too see how it works this weekend. down plates are 2 inchs longer and top plate and side panels have an angle on them ,we will see how it works.

 

[nash1970]

Re: super fin - long post

subscribed

 

[Frank Acampora]

Re: super fin - long post

Hey, Jo Lin: Those of us who are a bit anal (Mr. Monk is my personal hero) think that if it don't look right, it aint gunna work right.

 

[MRS]

Re: super fin - long post

What tabs are you running on the boat now? If they are not working right they might be to small for your boat. Just wondering cause they usally take care of the plaining problems... I did look at your photos but could not see any tabs hooked up....

 

[JoLin]

Re: super fin - long post

Hey, Jo Lin: Those of us who are a bit anal (Mr. Monk is my personal hero) think that if it don't look right, it aint gunna work right.

Point taken and no slight intended. IMO, it already looks 10 times better than anything I could turn out

 

[scoutabout]

Re: super fin - long post

I'm really impressed you'd see it, make it, then test it. Looks very professional. Doesn't surprise me at all you're getting more rudder authority and stability considering the combination of adding control surface and and probably concentrating the thrust too. Nice work!

It will be interesting to see how the next generation looks and performs. Pics please!

If you were concerned about stress you could shape and extend the mounting surface to move extend further forward on either side of the outdrive under your hydraulic rams.

 

[45Auto]

Re: super fin - long post

LMAO!! Where are all the Hydrofoil haters??

Someone puts a homemade Hydrofoil on their boat and everyone is amazed that it gets on plane quicker, handles better at low speed, is faster on top speed, planes at slower speeds, etc.

Yet the commercial ones will damage your outdrive, make your boat unsafe to turn, make it slower, etc, etc, etc!

 

[This_lil_fishy]

Re: super fin - long post

I don't use either (hydrofoil or tabs) but I'd have to say what we are talking about here is pretty removed from a simple hydrofoil.

Ian

 

[scoutabout]

Re: super fin - long post

...

Yet the commercial ones will damage your outdrive, make your boat unsafe to turn, make it slower, etc, etc, etc!...

My own (and admitedly statistically insignificant) experience with one on my Sea Ray's Alpha drive for ten years and hundreds of hours showed no hint of what you suggest is claimed about handling and outdrive damage.