Stern drive in saltwater

[jsc7]

I have read some forum posts (on other web sites) that state having a stern drive moored in a slip in salt water is a "fool's errand" because corrosion is constant and problematic. Moreover, if the bellows lose their integrity then the boat can sink.

How accurate is that?

[mickt243]

Not particularly accurate.

Yes they do have their own unique maintenance requirements, but they aren't particularly troublesome. Like any other system they have their positives and their negatives, some love em, some love to hate em, others just use them because they do their jobs.

Mine (merc bravo III's) have been kept in salt water for 11 years so far with no major issues. Yes, I would prefer shaft drive diesels, but the boat I bought had gassers with sterndrives, they have done everything I have wanted them to......

[NewMoon]

My 26-footer's Volvo KAD44P diesel with 290 DPE sterndrive spent 2-4 months continuous on the water almost every summer from 1998 through 2015. Cruising BC and SE Alaska 2000-3000nm each.

There were barnacles etc to clean off, which was time-consuming, but otherwise no big deal. And, leaking bellows on a Volvo drive does not sink the boat.

[tuffr2]

I would say it is much better to get the sterndrive out of the water. That is a big advantage of an outboard is they come out of the water completey. Even in fresh water a sterndrive will get moss growning on it.

Of course if you use the boat often woukd be best. Sitting in saltwater for long periods of time will cause attacts underwater as well as big birds will perch on it from above.

I am in Florida, there are 1000's of crappy looking boats.

[fstbttms]

Sterndrives were not designed to live in the water 24/7/365 and nothing good comes from leaving them in the water.

[jsc7]

Clarification: this is for a boat in New England. So, it would be in the water April through October and laid up November to March.

[Ahneema]

I agree with NewMoon and mickt243. They have there unique issues but you can work around and make them last a long time.
1. When you have the boat taken out of the water for bottom painting or other maintenance, ALWAYS inspect the bellows and drive.
2. Make sure you regularly get bottom cleaning done and a good bottom cleaning guy will give you a heads up on any issues.
3. As for your engine...before I Place my boat in the ocean, I installed the Volvo Penta Nutra-Salt system. My engine was ocean cooled, and i didn’t have the luxury of being able to flush the engines as you do on an outboard. Basically, you turn the system 9n during the last minute of operation and just turn the engine off. Neutralizes saltwater in the engine.

[mikecambrai]

Outdrives are designed for fresh and salt water. In the coastal UK waters, we are always in salty water. To keep everything OK, you have to check your anodes regularly, at least once a season. The anodes are in the outdrives (special anodes), and there are other anodes where you have seacocks. these anodes should be linked together to ensure that there potential is always the same, and of course, all the anodes have to be of the same material. I use aluminium because I go into fresh and salt water, but the choice may be made by the availability of the special anodes for the outdrives.

[Cheechako]

Keep the zincs fresh for sure. I was amazed how quickly they deplete on the OD. Problems may develop, but it's done all the time.

[Ahneema]

Yes! Forgot about those badboy zincs! My newest boat has twin Yanmars. Fresh water cooled but uses ocean water through heat exchangers. There are zinc anodes for the heat exchanger! Glad you guys mentioned the zincs!

[Cadence]

Originally Posted by fstbttms

Sterndrives were not designed to live in the water 24/7/365 and nothing good comes from leaving them in the water.

Good for trailer boats and that's it. A fresh water lake might not be to bad?

[CaptTom]

Our last boat spent 10 seasons in salt water, summers May-October. It had a Merc BIII outdrive. Between a cathodic protection system (Mercathode) and all the anodes they had on them, I never had a problem with corrosion. I did end up scraping a lot of barnacles and re-painting a time or two. Not really a huge chore.

The bellows had a very slow leak once. It took me a long time to even find where the water was coming in. No danger of sinking, at least from the failure I had.

I personally prefer to avoid outdrives, but if that's what was on a boat I otherwise liked, I wouldn't cross it off the list.

[flyingfin]

No problem, unless you are the mechanic who has to make repairs to the outdrive. Aluminum dunked in salt water is better than a welding stick for joining metal parts together. Outdrives and outboards are best stored on lifts or dry racks and washed after every use if you expect them to last.

Stop by a marine mechanic shop one day and watch them pull an outdrive apart. If not, be prepared to Break Out Another Thousand!

[CaptTom]

Another point; a single outdrive can have pretty good steerage in reverse, giving you some handling options you don't have with a single inboard. It's the opposite in the case of twin outdrives. The pivot point wants to be between the props, so it takes more thrust to get any spin out of them, compared to inboards with the props farther forward.

[hobopacket]

As someone that has a merc with the alpha drive. I wouldn’t do it. Growth gets it really hard to reach places. I keep mine on the trailer which works great. Trailer or lift kept boats. But if you have the money for maintenance, have at it.