B-3's in brackish or salt water

Captn TJ

Active Member
Sep 19, 2017
872
Catawba Island, Oh
Boat Info
2005 280DA
Raymarine E80
Engines
5.0 with Bravo 3
We have a 280 currently kept in the Great Lakes and debating moving down to South Carolina and keeping it in an estuary with brackish water. How much of a problem will the mercruisers and B-3's be (related to corrosion).
 
You will get various responses to this, here’s my experience.

My 2007 with Bravo3 has been wet slipped in salt water 6 months per year for its entire life.
Myself and the previous owners have replaced the aluminum anodes yearly, and painted the drive each spring before launch.

There is no corrosion anywhere on the drive. The horseshoe shaped anode on the forward edge of the cavitation plate takes the most abuse and only lasts one season. The others aren’t so bad, but they all get replaced yearly regardless.

Every winter the drive is removed and the upper/lower units separated to clean the 2-3 barnacles that grow inside there each season.

The original manifolds, risers and bellows were replaced at 11 years and 300 hours.

Does your 2005 have the additional prop shaft anode? Seems that the older B3’s, around 1999 or so, had corrosion issues.

The aluminum anodes are for salt/brackish water, I assume you have something else on there now for your fresh water application.
 
You will get various responses to this, here’s my experience.

My 2007 with Bravo3 has been wet slipped in salt water 6 months per year for its entire life.
Myself and the previous owners have replaced the aluminum anodes yearly, and painted the drive each spring before launch.

There is no corrosion anywhere on the drive. The horseshoe shaped anode on the forward edge of the cavitation plate takes the most abuse and only lasts one season. The others aren’t so bad, but they all get replaced yearly regardless.

Every winter the drive is removed and the upper/lower units separated to clean the 2-3 barnacles that grow inside there each season.

The original manifolds, risers and bellows were replaced at 11 years and 300 hours.

Does your 2005 have the additional prop shaft anode? Seems that the older B3’s, around 1999 or so, had corrosion issues.

The aluminum anodes are for salt/brackish water, I assume you have something else on there now for your fresh water application.


Magnesium anodes are the standard for the Great Lakes. My B-3's have anodes on the prop nuts and also on the pistons. Separately I also have anodes on the trim tabs - but of course that doesn't affect the I/Os.

The PO kept this boat in the water (likely at a hot marina), so past records show replacement every couple of years. We put all new anodes on when we bought the boat in 2017 , but it's in rack storage so corrosion is not an issue. Also the mercathode system works as we have it tested.
 
All good info. I would add -

1. Find out what others with the same drive in the same marina are doing.

2. Make sure the continuity circuit is correctly and completely connected to the drive using the Merc Continuity Circuit Kit (part #99940A2, costs about $30), and check this every year because the wires can break off.
 
Even in fresh water the BIII lasted about 12 years on my 280. Electrical current leak was a killer at my boat club.
 

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