Lower unit "fin"

[EJ3]

I am not sure what the name is for this, but it is the "fin" that is in front of the propeller that extends as far down as the propeller does.

Is there a name for this, and what is it?

Whatever the name is, it is bent on my OB. Not badly, it's more of a curve than a bend. Does anyone have advice to get it straightened out? Should I heat it up and lightly hammer it back into place? Should I just leave it the way it is? I have not ran it on the water so I am not sure if it is hindering anything or not. It is not twisted at all, just curved to one side.

Thanks!

 

[bgbass.1]

Re: Lower unit "fin"

If its not curved real bad you should be ok. you will know for sure when you get on the water

 

[Silvertip]

Re: Lower unit "fin"

Be aware that heating the skeg as it's called, also heats everything inside the lower unit including seals. Seals are rubber and will not like the heat. The skeg is also cast aluminum and "hammering" on it is not recommended. If you do some on water tests and things appear normal, leave it alone. The skeg is there primarily to kick up the motor should you strike something. If it were twisted, it could affect handling but a bend to one side or the other is not an issue.

 

[MikDee]

Re: Lower unit "fin"

You might try to put a block of wood on each side of it, and a large c-clamp in the middle, to try, and bend it back to shape, heat it with a hair dryer, or a heat gun first, if you can, to get it comfortably warm so it's not brittle. But, if it breaks, I'm not responsible,,, but that really shouldn't happen if you do it slowly, & carefully.

 

[Gary H NC]

Re: Lower unit "fin"

You may be able to bend it but most likely it will break.That cast aluminum is very brittle.
Like SilverTip said if it does not affect the way the boat handles leave it be.

 

[Texasmark]

Re: Lower unit "fin"

Gary and Silver are trying to help you. Leave it alone. I have a deflector on my engine (above the vent plate...keeps the leading edge spray outta da boat) that the previous owner must have hit a log and bent. I don't like it but to try and straighten it I will probably break it so I just don't look at it.

Mark

 

[pecheux]

Re: Lower unit "fin"

That lower unit 'fin" got badly bent on my 115 Merc after hitting bottom (rocks).

My mecanic straightened it out ... but I dont know how he did the job ...

 

[maxum247]

Re: Lower unit "fin"

If it's not bent to one side to much and it ends up just bothering you ever time you look at it, a skeg guard might help to please the eye. I beleive partial guards as well as full guards are available. These are designed to keep the skeg from wareing down over time and getting nicked up. Cosmetic wise this could be an option, but are kind of pricey!

 

[Frank Acampora]

Re: Lower unit "fin"

Castings are brittle but can be worked. Forging is the process whereby a cast part is strengthened and the metal molecules aligned. Usually it is done on a red hot piece of metal hammered in a press, or on an anvil like the old village smithy used to do, but it can be done cold. This is the simplistic explanation.

IF you lightly work the bent skeg with an eye to very gradually taking out the bend you will be forging it (sort of). You must back up the other side with a heavy piece of steel and firmly TAP TAP TAP the skeg with a relatively light hammer--say 16-22 oz. Hold the hammer lightly and let it freely rebound. We are trying to coax the metal into the shape we want, not force it.

HOWEVER: Most of us don't have the experience or patience to do it correctly and break the damn thing, which is what you are likely to do.

I have been able to straighten some and have broken some--but I am getting better.

Best course of action is to leave it alone. If it really offends your sensibilities or aestheticly displeases you, then try to straighten it but expect to break it.

 

[blouderback]

Re: Lower unit "fin"

Leave it alone. It will not affect your handling noticably. If you try to fix it and it breaks off, then you have a bigger problem.

 

[Chinewalker]

Re: Lower unit "fin"

I have straightened out several skegs & AV plates using Frank's method. A light ball-peen hammer on the "hit" side with a heavier one on the on the other side to take the shock. Takes awhile, but works well. Also a good idea to stuff some cotton in your ears when doing it... it's a noisy job.
- Scott

 

[TOHATSU GURU]

Re: Lower unit "fin"

One additional warning...The cavity where the gears ride can be taken out of spec by trying to straighten the skeg. Using heat(IE high heat) can increase that risk.

 

[cc67]

Re: Lower unit "fin"

Whatever you hit, just go out and hit again from the opposite direction. Seriously, I've staitened anti-cavatation plates with a cresent wrench and a lot of patience.

 

[EJ3]

Re: Lower unit "fin"

WOW, I am suprised to see this thread getting attention again!

I have had the boat out and it seems fine. I have not done any "correcting" to the skeg.

But, as always, thanks for the input!