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my turn for a little bad luck
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Author:  RichA [ Sun Aug 24, 2014 11:24 pm ]
Post subject:  my turn for a little bad luck

Went past a spot I've gone past before without problems, and the tide was decently high to boot. Depth was reading 10 feet or more until a sudden metal grinding sound for a short time, just as the depth alarm sounded. Other than a little extra vibration (or was I imagining things?), and a slight decrease in performance, the boat worked fine, but a couple of the blades the forward prop are bent (see pics). Is this a thing likely to be fixed by a little metal massaging, or is it major work to repair it, or (yikes) will I need to replace it?

The damage appears limited to the forward of the 2 props. There is a small dent on the nose of the drive, and the skeg (apparently a patch placed the PO) is slightly bent, but I'm guessing those are either not critical or easily fixed.

Other than that, it was a lovely day on the water!

Image

Image

Author:  NiagaraChillin [ Mon Aug 25, 2014 12:22 am ]
Post subject:  Re: my turn for a little bad luck

Hitting the bottom (or submerged obstacle) with the drive is one of those things where you either get lucky and it's just some cosmetic damage to the prop and skeg, or its bad enough that the alignment is out of whack, gimble bearing damaged, the shaft is bent, the lower drive case is cracked, and/or the transom seal is compromised. Did you notice any vibration afterwards? Any water in the bilge? Any fluid leaking from the "dent" in the lower case?

Don't mean to pile all the bad things in one post, but these are things that can happen after a good smack to the drive. The prop and skeg can be corrected with the metal massaging you mentioned, if its anything else the drive will need to be removed and checked out.

Author:  204Angler [ Mon Aug 25, 2014 8:16 am ]
Post subject:  Re: my turn for a little bad luck

My want to pressurize the lower unit. This is the best way to check the case for leaks. The other ways involve lots of hoping and watching for fluid leaking and/or water intrusion into the L/U. I'm surprised it damaged your prop that bad and didn't spin the hub

Author:  Thalasso [ Mon Aug 25, 2014 8:48 am ]
Post subject:  Re: my turn for a little bad luck

Dinged mine a couple of times and there is no better fix then this type of place.
http://www.northcoastproptech.com/

Author:  RichA [ Mon Aug 25, 2014 9:00 am ]
Post subject:  Re: my turn for a little bad luck

I didn't see any big differences, either with water in or oil out, steering, etc. There was no jolt to the boat, just the noise, so I don't think the leg took a big hit. Speed was maybe 10.

The dent on the nose is small enough that it might even have been there and I never noticed it before. I only found it by running my hand around it; can't really see it because it's on the front.

The level of vibration seemed consistent with the damaged blade, and I couldn't swear that I'm not imagining the increase in vibration.

Sounds like there is a pretty good chance the prop can be repaired, so I'll try to find someone to do that.

Author:  blue dragon [ Mon Aug 25, 2014 9:14 am ]
Post subject:  Re: my turn for a little bad luck

Been there, done that. Both the prop and the skeg can be fixed.

Author:  taz42169 [ Mon Aug 25, 2014 9:30 am ]
Post subject:  Re: my turn for a little bad luck

INSURANCE! You may be able to file a claim for repairs (to the drive if warranted) and/or new props...just a thought, especially if you were in a channel.

Author:  Obie [ Mon Aug 25, 2014 3:36 pm ]
Post subject:  Re: my turn for a little bad luck

Been there and done that. I took the opportunity to put more cup on my F3 props to make them into F3.5s (between an F3 and a F4). This is a better fit for the elevations where I boat. The F3.5 has almost too much effective pitch for Lake Tahoe (6,200 ft) and almost too little for Lake Powell (3,650 ft).

Author:  Graham R [ Mon Aug 25, 2014 4:32 pm ]
Post subject:  Re: my turn for a little bad luck

Obie wrote:
Been there and done that. I took the opportunity to put more cup on my F3 props to make them into F3.5s (between an F3 and a F4). This is a better fit for the elevations where I boat. The F3.5 has almost too much effective pitch for Lake Tahoe (6,200 ft) and almost too little for Lake Powell (3,650 ft).


Wow, I didn't realise altitude made that much difference ( not surprising really as here in the UK most boating is either at sea level or only a few hundred feet above it)

Is it the lower air pressure/ lower oxygen level being lower affecting horsepower ?

My 245 Sundowner had F5 props.

Author:  LouC [ Mon Aug 25, 2014 6:15 pm ]
Post subject:  Re: my turn for a little bad luck

Yes it does, air density is lower, a carbed engine jetted properly at sea level will be set too rich at altitude. So it will need leaner jetting for high altitude. FI engines are less affected because some can compensate for altitude but it will still make less power. It will also make less power and need a lower pitch prop to pull the correct rpm.
Some engines even had different gear ratios in the drive (shorter gearing) for altitude.

Author:  Obie [ Thu Aug 28, 2014 4:55 pm ]
Post subject:  Re: my turn for a little bad luck

An engine loses about 3% of it's horsepower for every 1,000 ft above sea level. So at Lake Tahoe I have only 81% of the listed horsepower while at Lake Powell I have 90% horsepower. It makes a real difference in maximum RPM and in maximum speed.

Author:  RichA [ Wed Sep 03, 2014 1:53 pm ]
Post subject:  Re: my turn for a little bad luck

I took the boat to my mechanic to pull the prop and send it to "his guy". He took one look at it and said the front prop was junk. It could be fixed, but because it was rolled over so far, the amount of labor to do it would push the cost higher than getting a new one. :(

The back prop was pretty good, but I'm sending it off to get a couple of dings fixed up, and I'll be looking for a new front F4. Ouch!

I'm generally happy with the way the boat performs, and since the back prop is still good, I'll stay with stock.

Thanks!

Author:  NiagaraChillin [ Thu Sep 04, 2014 1:58 am ]
Post subject:  Re: my turn for a little bad luck

RichA wrote:
I took the boat to my mechanic to pull the prop and send it to "his guy". He took one look at it and said the front prop was junk.

Is this the same "mechanic" that said no parts were available to repair your raw water pump? Would be highly suspicious of any mechanic whose stock answer is "can't fix it, gotta replace it with new".

Author:  blue dragon [ Thu Sep 04, 2014 8:19 am ]
Post subject:  Re: my turn for a little bad luck

I call BS on that one, my front prop (click me) was just as rolled over as yours, it cost me $300 to fix, the cheapest I got a new one for was $650
I would say to check the coupler between the upper and lower drive, thats what mine looked like after

Image

Author:  RichA [ Thu Sep 04, 2014 11:15 am ]
Post subject:  Re: my turn for a little bad luck

blue dragon wrote:
I call BS on that one, my front prop (click me) was just as rolled over as yours, it cost me $300 to fix, the cheapest I got a new one for was $650
I would say to check the coupler between the upper and lower drive, thats what mine looked like after

Image


Did you go to a local place, or send your prop somewhere?

One of my blades has a crack/tear about 1 inch long, and the edges are not as smooth, but I don't know how much difference that makes.

I just bought a reconditioned prop off ebay for $375. I think I'll take some more pics of the bent one and send them around to prop shops over the winter to see if someone is willing to make a deal during off season.

How do you get to that coupler to check it? Did you have any symptoms of the damage? Mine seems to work just fine, though I won't know for sure that the vibration goes away until I run with fixed props.

Thanks,
-- Rich

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