Bravo iii corrosion

[YachtRock]

I’ve been keeping my eye out for a sundancer 240 and have looked at a number of them. I just looked at a 2006 that’s been on freshwater it’s entire life. I was surprised to see a good amount of corrosion on the fin and exit shaft part of the outdrive. It seems as though it sat in a slip and someone didn’t stay on top of the zincs. I’d like to see what everyone else thinks.

Not sure if you can see in the photos, but it even looks like there might be some perforations in the aluminum at the gusset part of at the exit of the housing where the props are. I’m assuming the corrosion looks similar where one can’t see the bearing and seal surfaces. Called around and a housing, bearings, seals and zinc kit is going to be $3500 plus labor. Am I working too much about this corrosion?

 

[El Capitan]

No. You’re not. That’s the corrosion you can see.

I lost a BII drive to electrolysis. It cracked in the front part of the bullet lower unit.

That SS prop isn’t helping either. You basically have a battery there.

Good luck

 

[scoflaw]

Seen that before in freshwater, some people think only salt can cause that type of damage. Wrong

 

[Chip S]

I saw that type of corrosion when someone used zinc for the anodes in freshwater. Freshwater requires either aluminum or magnesium anodes.

 

[KevinC]

I would walk away from this one depending on the price. That's probably just the tip of the iceberg. If the owner let this happen who knows what else was overlooked.

-Kevin

 

[YachtRock]

Thanks for all the replies, good info and confirms my gut feeling about it. I’m not sure there’s even a right price for me to get the boat. Low hours don’t matter if you’ve totally neglected it. The fore deck was heavily oxidized as well, just too much wrong that can add up fast to fix. Plenty of nice boats out there. I’ll find the right one.

 

[DWABoat]

Good call on passing on this one.

I am warranty replacing two lower units on a work boat using duo-prop outdrives after a year and half only fresh water. The corrosion system failed.
The outer portion was not eaten too bad. The bearing carrier behind the props ate
away so bad it started leaking oil from the seal. That is what tipped us off initially.

If you see that kind of corrosion on the outside, El Capitan is right, what is inside is likely worse.

I would not walk...I would run.

I started testing my corrosion protection using a meter and hanging zinc since then. I read millivolts at the drives to determine if the impressed current system is working.

 

[Forrest SeGuin]

I saw that type of corrosion when someone used zinc for the anodes in freshwater. Freshwater requires either aluminum or magnesium anodes.

How can you tell what type of anodes is on your boat? I'm dealing with some pretty bad corrosion and when we bought it they installed new anodes. Thanks

 

[paulswagelock]

For $60 just change them to the correct type for your water to be certain.

 

[Forrest SeGuin]

For $60 just change them to the correct type for your water to be certain.

Anyone know what is best for NY freshwater?

 

[paulswagelock]

For most places with fresh water, magnesium are the correct choice. However, sometimes they can be a little too reactive and go away too quickly if the water is slightly brackish. Ask your boat neighbors and see what they have, but probably magnesium.
Tecnoseal 20805mg is a lower cost but very good choice.

Also check your mercathode system to make sure it is working.
Here is a quick check method:

Check for 12v on the center 2 screws of the mercathode controller. When the boat is in the water, disconnect the orange wire that comes from the anode at the mercathode controller. Set the digital reader to show milliamps. Connect the black meter lead to the terminal on the controller. Connect the red meter lead to the end of orange wire. If using the blue or black Mercathode controller, the reading should be 25 or less milliamps, to as much as 200 milliamps in saltwater areas. If using the red Mercathode controller, the readings should be less than 25 milliamps in fresh water areas to as high as 400 milliamps in saltwater areas.

 

[27Sherwood]

OP YachtRock appears to be gone, wondering if he ever found his 240 Sundancer? Even though I'm presently having issues with the 98 240 I've been working on, I think this is a great choice for that class of boat! Wondering too if that Bravo III pictured ever had any type of anode.... His pics are good but do not show the business end of the prop. Her 98's drive looks practically new.

How can you tell what type of anodes is on your boat? I'm dealing with some pretty bad corrosion and when we bought it they installed new anodes. Thanks

Forrest I'm sure there's a way to see what was put on there but as noted by paulswagelock, for $60, just change them. If you find out later that they were the correct type, (you said they were just put on so I'm assuming they're new) simply use them next season.
Remember, you can only keep the corrosion from getting worse, you cannot reverse any of it....