Libre Prop Issue...

[Libre]

I have had prop issues for a couple years now. I thought the problem was gone once and for all, but my diver just informed me yesterday that he is starting to see cavitation on both props, which I bought used from SD Propellers about 7 months ago. It's on the outside of both props closer to the tips.

I'm not sure if it's the same problem as last time. Last April I noticed I had chips on the blades. So while I had the boat hauled out I had the Shelter Island Boat Yard repair them. Then about 3 months later we noticed they were wearing out again. Little pin holes starting to be created. We thought maybe that the zincs weren't working because the out drive was painted, but they were still burning. We sanded off the paint put new zincs on and the props continued to get worse. But the zincs were burning as they should. They ended up getting worse again so we checked for electralosis and didn't read any. By the time I got the blades off they were in really bad. Pin holes, chips and really worn out.

I took them over to SD Propellars and he assured me the props themselves had gone bad. Pointed out some pits in the casing. Said I shouldn't even had bother with fixing them. Luckily he had a used set of 4's that he sized down the 3's for me. That was a solid 7 months ago. Everything was good until about 3 weeks ago my diver noticed some wear.

I spent $400 to get the original props fixed. Then bought a used set for $400. WTF? Any ideas?

Tony

[NoSlack]

Awhile back Joe was eating holes in his outdrive because it was softer than his stainless props.

If I remember correctly he had a boat on his dock with a bad charger and it was eating away at all his neighbors zinks and soft metals.

Installing a galvanic isolator will help with that problem. Do the newer Blackmans come with a galvanic isolator?

One more thing to check. There should be a ground wire or strap the bonds the transom shield to the engine.

here is a link for some isolator info. http://www.yandina.com/acrobats/GalvOwnManual.pdf

Mike

[Honeygirl]

Tony, The Glavanic isolator was one off the best investments I ever made. I was eating my zinks about every 6 weeks. Now I do them about every nine months. I also had prop problems when I first bought my boat. I went through two sets of props due to cavitation not from electrolisis. The way the Blackmans are set up, we get alot of air past the transome and if you have a higher horsepower motor, then you're going to eat props due to air passing over the prop and not grabbing water at higher speeds. After talking with volvo penta they stated that my pakage came new with stainless props. The old owner prefered aluminum. He like the performance better. I switched back to stainless and like the performance much better. With aluminum you get a 4 blade insted of a 3 blade. he stated it came up on plane better. I have a extra set of C3 SS you can test if you would like. They will be the same as your A4. Joe

[Libre]

Mike, I will look into the ground strap to make sure it's connected. We checked that last time and it was. But I will check it again to make sure. I will also look into the Galvanic isolator. Joe, that makes sense. When I bought the boat it only had 235 hrs on it. Those hours were over a 3 year period and it was trailored. It now has 612 hours. The boat gets used a lot more and it's had aluminum props from the start.

[Libre]

Interesting...I was just reading about the Galvanic isolator. I never plug in my shore power. Even when it has sat for a couple weeks their is plenty of juice. I think I have used it twice only when I had bait in my tank over night.

[Honeygirl]

could be from a boat next to you also. Zack can't plug his boat in at all it eats everything including his outdrie

[hijole]

I have made every mistake possible. So my 2 cents.
Besides what has already been mentioned, I learned not to paint (just greese) any of the stainless rings in the middle of the props and make sure the SS nuts and washers that tighten the prop also touch the the shaft and the prop. The rubber in the middle stops direct flow. When I put on each prop I use my meter to make sure I have continuity from the blades to the zinc.
When you take the boat out of the water check the continuity of the blades to the zinc before you romove the props to see where the problem might be.

[Al Gagnon]

I have twin shafts on my boat. Notice my port prop developed some pitting holes around an area that looks like it was repaired with bronze welding. I hit a lobster rope last year and tweeked the tip of one blade slightly. Well now it looks like more than one blade is bent and getting somepiting. Trying to remoe the prop and it wont budge. Going to try hitting with salt away and then try ice on shaft and heat on prop. I remember someone saying you need to put some kind of lube on the shaft before installing the prop. Anyone remember what the lube was? I am going to have Ed at Pacific Props do the work, in Spring Valley.

[yellowfin1]

Whoah,
Hold on there. Before applying heat to the shaft or prop, you need to be aware that doing so could melt or damage the rubber shaft seal which could cause bigger problems.

I did what Jeff did. Apply a good lubricant to the shaft while the Outdrive is in the up position. Let it soak in for a day or so, and try tapping on the prop sleeve with a hammer (not too hard). If it does not break it free, just keep applying the lubricant and tapping on it. I also applied very hot water several times. After about a week, she finally slid off.

Good luck,
Scott

[DOGHOUSE26]

Whoah,
Hold on there. Before applying heat to the shaft or prop, you need to be aware that doing so could melt or damage the rubber shaft seal which could cause bigger problems.

I did what Jeff did. Apply a good lubricant to the shaft while the Outdrive is in the up position. Let it soak in for a day or so, and try tapping on the prop sleeve with a hammer (not too hard). If it does not break it free, just keep applying the lubricant and tapping on it. I also applied very hot water several times. After about a week, she finally slid off.

Good luck,
Scott

I think he's an inboarder Scott

[Malu Lani]

On Time Out we used a prop tool to remove the prop