What happened to my lower unit... check out these pictures

[Primo321]

Morning all,

To my awful suprise after pulling my boat out last night, I saw that one of the 4 lower unit fins was completely broken off along with a chunk of the metal that holds it.

Its a 1969 mercruiser 140 hp.

Can I still run the boat with it in this conition?

Should I remove the fin from the other side and just leave the two large fins closest to the prop?

Any recomendations on how to fix this?

Thanks

 

[Don S]

Re: What happened to my lower unit... check out these pictures

It's an outdrive, not an airplane wing. The cavitation plate was never designed to have wings on it like that.
All it takes is to hit something with those fins and it will break the cavitation plate off.

 

[alldodge]

Re: WTF happened to my lower unit... check out these pictures

Re: WTF happened to my lower unit... check out these pictures

Morning all,

To my awful suprise after pulling my boat out last night, I saw that one of the 4 lower unit fins was completely broken off along with a chunk of the metal that holds it.

Its a 1969 mercruiser 140 hp.

Can I still run the boat with it in this conition?

Should I remove the fin from the other side and just leave the two large fins closest to the prop?

Any recomendations on how to fix this?

Thanks

First I have to ask why do you have two foils on your outdrive? The foils should only be used only on the rear. I would remove the one from the front of your cavatation plate. Find a welding shop that specilizes in aluminum and see what they can do to repair it. May be able to go to a prop repair shop and they could do it.

You can run it like that but it will continue to come apart because of all of the extra load on the plate. You may also have some unseen cavatation problems due to air bulbles forming froman unsmooth surface.

 

[robert graham]

Re: What happened to my lower unit... check out these pictures

Looks like somone added those bolt-on fins to your cavitation plate to help the boat get up on plane quicker. Also part of your cavitation plate is broken off. You could just remove all those fins and leave them off or replace with one new, large fin. Your boat may be just fine without those fins, but may take a bit longer to get up on plane. Good Luck!

 

[ziggy]

Re: What happened to my lower unit... check out these pictures

looks like ya got them stingray fins that i used to have. though you have them times 2.. never seen that before. what likely happened to you is just what dons said. ya hit something. fwiw, same thing happened to me. broke my anti ventilation plate just like yours too. though i only had one set on. after the breaking off of my plate, that was the last straw for me. off they came never to be used again. as for the repair. as stated, someone with good welding skills can put it back to like new. on my old skow that i had, i went with a welder first. all he did was melt more anti vent. plate away.. bummer. gotta get a good welder. so instead of running as is, i went to the hardware store and got 2 pieces of flat alum. stock. cut to fit and made a sandwich of what was left of the anti vent. plate with the two pieces of alum. stock. as far as i was concerned, it performed just fine. didn't note any issues. looked ugly but at least water didn't ride on the break. it rode on my engineered pieces...

what happened to you is the reason i'll not go back to a wale tale of any kind.... if i gotta have something, it'll be smart tabs or real tabs. but anything that bolts to my anti ventilation plate..

 

[Primo321]

Re: What happened to my lower unit... check out these pictures

Thanks for the input. Glad I can at least enjoy the rest of the season without a costly repair.

This is my first boat that I got 3 months ago so the lingo is new to me.


Not sure why the extra fins were there but I will be removing them before this afternoons fishing trip.

 

[alldodge]

Re: What happened to my lower unit... check out these pictures

I put one on the rear of my Rinker short time after a bought it in 95 and it works great. Comes out of the water quick, stays on plane with less throttle, the only thing it hurts is top end, but I'm not a go-fats kind of guy. It's just putting it on up fr4ont was the bad idea.

Have a great day fishing

 

[Apollo75]

Re: What happened to my lower unit... check out these pictures

I did some research --- seemed fins caused an issue with extra lifting load on the out-drive that was not recommended. So, I installed old style wrench in hand adjustable trim plates --- they worked great in the full up position --- then I installed a 4-blade Solas prop that lifts the stern this year --- I do not know if that prop puts too much load on my old out-drive or not --- now I can adjust about 300-rpm and smooth planing with the out-drive trim.

I adjusted the out-drive trim too far once --- lost grip --- and the engine over revved and threw out a bit of carbon. I think it runs better now

OFM

-------------------------------------------------------------------
We should do more boating and less wrenching.

 

[Gary H NC]

Re: What happened to my lower unit... check out these pictures

Junk the fins....
If it has issues getting on plane after removal look into a set of Smart Tabs..
It may actually handle better without the fins anyway...