Propeller corrosion

A

Another Toy

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Jun 25, 2006
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21973
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The welds on my stainless steel propeller have disappeared from corrosion, the rest of the propeller is unaffected. I had always seen some white fuzz on my Bravo ll outdrive. I removed the corrision and repainted the damaged area about the last 6 times I used the boat about 30 hours water time. I figured it was caused by all the new navtronic install in the boat this last summer. Upon closer inspection of the boat system, a broken fuse was discovered on my Outdrive Mercatode system I have replaced the broken fuse and replaced all the zinc with aluminum anode. I will be testing the boat this weekend and will be ordering another new stainless steel 4 blade propeller this week. Hope I have found the cause of the problem. Anyone have another other ideas...?
I keep the boat in dry storage.

Another Toy
 
Interesting. The stainless steel propeller should be about the last thing that should be corroded in the system as it is the most noble of he metals used.
I had a new 89 Sea Ray with a Bravo 1 OD. Merc replaced the lower unit 2 times under the warranty. The last time they sent the factory guys from Oklahoma up to Village West to check the boat in the water. Their conclusion, after puting meters on everything including the water and all electrical connections and shore power, was that the Sea Ray provided galvanic isolater did not provide adequate protection. They installed thier own more expensive variety as well as installing a second Mercathode. The latter improvement is quite common. I also had experimented with remvoing the stainless propeller and installing an aluminum one. This also slowed down the corrison issues but also dramtically reduced the boats performance.
These issues are common to others that have had similar problems. I would suggest installing the best galvanic isolater you can purchase. See page 364 of the current West Marine catalog. Good luck and regardless.... Merry Christmas.
Incidentally, following that experience, our next boats were put on a lift and we never had any further problems, including a B-3 unit on a 2001 Maxum 29, and that year and model outdrive had manufacturer noted corrosion issues. It is my personal obseravtion and philosophy that there are no good outdrives. Put a hunk of iron (engine block) in a boat, connect it to an aluminum leg (outdrive) and then place the whole thing in water is basically making a battery and something has to give.
 
dugs is right about SS being most noble of the metals on a boat. You say the welds showed corrosion. I wonder if maybe the welding material was a lesser alloy?

Since you keep your boat in dry storage, you should very little corrosion. That corrosion would be a result of where you dock the boat during the weekend. Though the blown fuse didn't help the situation at all. Are others in your marina experiencing a lot of corrosion? If so, mention it to your marina management. They may have an electrical issue on their docks, etc.

The island of Bethel Island is one huge battery in the water due to very old power coming onto the island and lots of out of code power going to a lot of those docks around the island. It really pays to keep your boat stored out of the water between uses. I use an air-dock for that purpose.
 
Thank you for the return/advise. I went for a cruise with my wife today from Whiskey Slough Marine(WSM)to the H&H cafe for lunch. About 7 hours water time. I did not see the active corrosion like before. I will take your advise and check another Galvanic Isolator. Also I have a 2500 watt AC inverter on the boat and need to consider how to connect ground to the new isolator system. I have also change back to my old allumium propeller. My damage Mach SS propeller was one for the frst 4 blade models made for the Barvo ll. I think there might have been a problem with the type of welding rod used. My next propeller will be a single piece casting.

In the early 1990's I had my boat at Village West for 2 weeks, while I had a 3rd axel added to my trailer. That was the first time I had see any corrosion on my outdrive and I was not connected to shore power. At WSM there is no shore power on the docks. I use my Honda genset to save my batteries. All my navtronics on the boat is new and I know the Raymarine E-80 uses 90 watts of power. Also I have the microwave and refig also. I think this fight I having with corrosion will be on going now. Corrosion can be controlled but can not be arrestd. This is also a major problem with airplanes.
 
I wonder if your Honda genset is contributing to the corrosion? I know nothing about it, but a portable genset may not be bonded to the boat.......perhaps there is someone on this forum who knows the answer to my question. You might have to pose it on the larger ATC or Engines, Electrical and Plumbing forum to get a broader response.

Good luck!

BTW, how is the food at H&H? Is it still Mexican or what? I haven't been there since they changed owners.
 
In general aluminum develops a film or oxide which has a very high electrical resistance, so I would think that it would not make a very good sacrificial anode. aluminum also tends to corrode by pitting rather than uniform dissolution. There are probably alloys that are better, but I would stick to zinc.
I dry store my boat at Bethel, but have about 400 hours on an early Mach SS prop without any corrosion. The only problem I ever had with the (zinc) sacrificial anode (which was original from 1991 and still in good shape) was last year when the bolts came loose and it fell off!
 
quote:
Originally posted by bigwaveohs

In general aluminum develops a film or oxide which has a very high electrical resistance, so I would think that it would not make a very good sacrificial anode. aluminum also tends to corrode by pitting rather than uniform dissolution. There are probably alloys that are better, but I would stick to zinc.

Click to expand...

Zinc anodes are designed to work in saltwater. Boats that live in fresh or brackish water should use aluminum or magnesium anodes.
 
Thank you again for the information. This weekend I will be going to WSM to inspect my outdrive & prop after everthing is dryed off. It looked a lot better with the Mercatode system working again. I will be checking all the grounds and anodes. I bought my boat new in 1990 and have 550 hrs on it. This is the first time I had any problems. The engine was overhauled last March, and there is 40 hrs on the engine since OH. I think that is when the problems started. I used the boat about 3 times at Rio Vista. I'm now in fresher water at Whiskey Slough Marina. H&R cafe did not have a very big selection to choose from, may be it was the off-season. I think the best Hambrgers are at Orewood. I plan to be using the boat again some time in mid January. How is the food at Bethel Island.......?
 
When it comes to breakfast and hamburgers, my preference is Lundberg Landing. It has plenty of docking but isn't a "fancy" place. Dinners are not great, but the price is right!

Paradise at Sugar Barge has lots of great docking space and sells fuel. Also has a pump out. The food is very good. They recently expanded the menu and the new choices look very good. I haven't had time to try them yet...... I love their freshly made French Onion soup!!!!! They are somewhat pricey, but you get good food, good service and great ambiance!

The final On-The-Water restaurant is Rusty Porthole. Their food and their service are inconsistent. I haven't eaten there all year. But I'll be there for the Frozen Bun Run on New Year's Day. They will serve a limited menu due to the crowds. They are famous for Bloody Mary's if you drink them! Then they will close the restaurant and bar for anywhere from a couple of weeks to a couple of months. They also have lots of dock space except on New Year's Day! This is THE place for Karaoke [th] when they are open again.

There is a new restaurant in downtown BI called Marshall's Bistro. Great food and ambiance! But it isn't on the water.....if you belong to a reciprocating yacht club, you can tie up at San Joaquin Yacht Club and walk to town to get there. It's about a 20 minute walk and worth it! They have fabulous hamburgers!!!! Prices match the quality of food, service and ambiance......

BTW, it sounds like something was done incorrectly when you had the boat overhauled. Either they blew the fuse then or they hooked up the bonding incorrectly. And I would worry if my zincs lasted that long! Mine last about 1-2 yrs which seems about normal........
 
From Mercruiser:

Zinc anodes are suitable for pre-2001 Mercruiser outdrives that operate in salt or brackish water, replacing deteriorated original zinc anodes.

Aluminum anodes are more active than zinc anodes and suitable for Mercruiser outdrives that operate in salt, brackish or fresh water. Since 2001, all Mercruiser outdrives with stainless steel propellers were delivered with aluminum anodes.

Magnesium anodes are highly active and suitable for Mercruiser outdrives with stainless steel propellers that operate in fresh water only.
 
Mercruiser had problems with their B3 drives. The stainless props didn't get along with the drives. (dissimilar metals) They're very aware of the problem and have several solutions. Aluminum props or better anodes. I wonder if you're having the same problems.
 
FB - you are right...! All my problems started after, first I had a head gasket replaced ($2500). 4 hours latter the engine spun a bearing and fused the connecting rods to the crankshaft. It took the same shop 11 months to OH the engine, I also had to pay up front for the engine OH ($5000). and another $3800 to remove and install the engine. After the engine was reinstalled I also started having higher oil temperatures/lower oil pressures then before. My outdrive is making a clicking sound now (started in trailer up position...?). The outdrive is also damage because it was draged across the shop and into the yard in the full down position (1/4 inch ground off). My prop had blue paint and also blue paint under my white swim platform (damaged by another boat). I have had 2 props damaged by this same shop from reparking the boat...! The side of my boat is also damaged and another boat in the shop had fresh damage the matched my location/height/color of damage, and I know the boats were parked side by side.
A lot of electrical problems started after the engine was installed including my propeller corrosion. My radar & radios were not working and I had it all replaced $5500. During the time my engine was being OH I started finding thing missing from my boat and several times found signs that other people have been sleeping in my boat's aft berth and animals have been urinating on my trailer's mag wheels while parked inside the shop.

I am now trying to decide to stay with an Aluminum (3 blade) propeller or another SS (4 blade) propeller.
Tomorrow I will be at WSM to back-flush my oil cooler, if I run the engine I will get an oil sample and send it to the lab for analysis, also check the control (fwd/rev) rigging on my outdrive.

And I will be coming to BI soon to check out the restaurant & docking.

Thanks - Another Toy
 
Who is the shop which has so mistreated your boat?????? I want to know so I can avoid them. They sound terrible. Good luck to you. I'll be at BI a couple of weekends in January. Give a holler if you are around.
 
FB

I can be contacted by my:

e-mail hugodasilva_iarb2@gr5tmsn.com
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cell 650 921 2528

I'm an aircraft inspector 30 + years

Another Toy ( Hugo )
 
You've got mail, I hope......."hugodasilva_iar at msn.com" is that right?
 
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