What's this Accessory on my MC-1 Sterndrive?

[Andy J]

Another question as I still have so much to learn about boats..... This is a Pict of my MC-1 Sterndrive which has horizontal fin added to it which doesn't appear OEM from all the photo's I have seen.

What is the purpose of this?



Thanks,
Andy J

 

[Scott Danforth]

the purpose is to empty your wallet of between $40 and $150 and have who ever mounted it drill holes in the outdrive, thus weakening the anti-cav plate.

other than that, they dont work.

its a whale tail or what ever you want to call it.

other than that, remove it.

 

[poconojoe]

Welcome! And since you said you have much to learn...here's a couple of tips....Whenever possible, you should keep the drive down, especially during long storage. This relieves constant stretching stress on the bellows. Also, when running your engine, you should keep the drive below the trailering position. Steep angles are not good for the rotating u-joints.
It's a learning process for all of us. It's good that you are asking questions. Don't hesitate to ask. There's a ton of knowledgeable members here that can help you have a safe and enjoyable boating experience.

 

[Andy J]

Whale tail..... I can see that now.

Didn't know if it helped the boat plane out quicker. My Bimini will hop up on plane with trim completely down in 20-30 feet. Is this normal characteristic of my boat? It's a Tri-Hull

Seems like I only need to trim up to get boat in/out of the water or avoid objects in swallow water.

Appreciate your input

 

[JoLin]

It's possible that it helps you get on plane faster, but there are better ways of correcting that issue, if in fact there is one. I had a 16' Sylvan aluminum that came to me with a whale tail on it. I didn't care for it- it made the boat kinda "squirrely" at high speed.

I took it off and wasn't thrilled with the way the boat handled normally, either. It exhibited a LOT of bow rise on acceleration and took awhile to get on plane. Based on my own previous experience (with a 21'er) I mounted a pair of Nauticus Smart Tabs on the boat. Bingo! the boat popped on plane right away with nearly no bow rise, and the handling at speed was rock solid. No more "squirrel".

My advice would be to remove it and see how the boat runs without it. If you feel it helped you can either put it back on or buy the tabs... and I'd always recommend the tabs over the tail.

My .02

 

[JimS123]

horizontal fin added to it which doesn't appear OEM from all the photo's I have seen.

What is the purpose of this?



Thanks,
Andy J

The purpose is to enable the boat to plane at lower speeds, and keep the bow down for better visibility in the process. If installed correctly its better than sliced bread and cost effective as well. Alternate equipment, though maybe better in some cases, costs up to 10x more $.

Its not OEM because the boat companies didn't think of it first, and now patent protection has affected the marketplace.

I have them on all of my current boats, and won't be without one. But then again understand the "installed correctly" comment.

 

[DeepCMark58A]

A whale tail has it's place where it is effective. I have a 1448 johnboat with a wide tunnel in the back to accommodate raising the motor so I can run in less than 12" of water without the tail the prop blows out.

 

[Blind Date]

Whale tails perform differently on every boat. My little SeaRay 160 w/3.0 MerCruiser had one on it when I bought it. It was amazing how flat and effortlessly the boat planed with it on. No adverse effects on handling. I took it off, don't think it really needs it as it still planes out pretty easy without a lot of bow rise. But I did like how easily and flat it planed out with it on.

My advice is run the boat with it on and off and then make your own decision about whether or not to leave it on. I think some people end up putting them on because it is an easier and cheaper fix than properly propping the boat. I took the cheap 3 blade aluminum off the 160 and stuck a 19P High Five on it. Think I payed over $400 for that prop 25 years ago.

 

[Andy J]

Everyone, I really appreciate all the input and opinions on my Whale Tail, I will do some testing as suggested and see what the results are.

I have them on all of my current boats, and won't be without one. But then again understand the "installed correctly" comment.

Jim, do you have any reference material to share that would show correct installation? From my photo what is your opinion of it's mounting?

Thanks everyone

 

[JimS123]

Everyone, I really appreciate all the input and opinions on my Whale Tail, I will do some testing as suggested and see what the results are.




Jim, do you have any reference material to share that would show correct installation? From my photo what is your opinion of it's mounting?

Thanks everyone

The original mousetrap was the patented DoelFin. I tried one about 30 years ago and have always gone back to that brand every time I bought a new boat. The Whaletails, Stingrays, etc. are merely copies that were reversed engineered to work around the patent. Personally I believe that those "copies" are what has tainted the market.

The OEM instructions are quite clear. Broken cavitation plates and loss of speed are urban legends because the user didn't follow the instructions. If you have an outboard, engine height will supplement the performance. If you are propped correctly beforehand, the results will be dramatic. If you add tabs as well,..... well, you just have to do it to see the improvement. If you have an I/O, the results may be hit or miss because you have no engine adjustments to make.

I can't comment on your installation because I have never used your version.

 

[Lowlysubaruguy]

My older board had one on it that the dealer installed. It did increase a hole shot performance loaded example here 20 foot deep v 4.3 Mercruiser IO six adults 4 medium kids could pull a fat skiier out of the water with a lot less effort. We saw this crew in the boat a lot back then. I think we carried as much weight in beer as kids.

The cons porposing above 45 mph bad enough to make you not go above that, and it did not corner as tight.

I tried a few things the best results were a 3 blade ballistic SS prop. 55 mph light load 35 to 40 mph cruise speed very fuel efficient will pull a fat slalom skiier out loaded with little effort. Best prop for rough water a simple solus 4 blade aluminum prop $120 great all around performance 50 mph top speed 35 mph cruise . Either of which is pretty good results for the load.

I tried my fin with every prop and without, it it’s been in the attic for 20 years.

 

[Andy J]

Whale Tail Feedback.... Took me a while to get the boat running again

Mine is a Stingray. With it removed took 500 more rpm to get planed out and bow was much higher. With the tail could cruise 2500 on plane, without had to maintain 3000.

does porpoise a little easier with it on but overall boat handles better with it on.

Like some said depends on hull design. My 1972 Tri Hull Winner seems to like it!

Thanks for everyone's input, sure helps when one doesn't know much about boats. Thanks to this forum I am learning though.

Andy J