saltwater sterndrive experiences.

BOB TYSON

Active Member
Oct 5, 2017
295
Kansas City
Boat Info
2005 460 Sundancer (SOLD)
Engines
Boatless
Hi all,
We are considering (again) a different boating experience that would likely involve models with sterndrives operated in saltwater. Previous posts on other forums have suggested that sterndrives are ticking time bombs when exposed to saltwater. Others have suggested that there are a huge number of sterndrives operating along the coasts of Florida without any issues as long as you have closed cooling systems and store the on a lift or trailer. Any experiences you have had will be appreciated.
Thanks in advance!
 
I've owned stern driven boats my whole life. It's been my experience that if they're left in the salt water, that's when the problems/hard maintenance begins. I've always towed my boat to the water, so all I had to do was pull the drive each year, inspect, and replace the impeller.

I'll let others who have had drives that live in the salt provide more detail on that aspect of maintenance and what goes wrong
 
My current boat has always been stored on a lift or in a dry storage. Zero issues with the outdrive other than the bellows being replaced (once after 15yrs) and the water pump (in the outdrive on an alpha) service every couple of years. My old boat had twin Bravo III's and was stored in (fresh) water year around. I had a bad corrosion problem which turned out to be a malfunctioning Mercathode system - both outdrives were replaced under warranty. After that I didn't have any more issues, but it was a constant maintenance thing - replacing anodes, inspections and the constant worry about the health of those two outdrives sitting in the water all the time. Performance wise they were great, quiet, smooth and fast. When I sold that boat I swore that I would never have another outdrive boat that had to stay in the water. Outdrives on trailers or lifts, they are fine in my opinion, but if you want the boat in the water year around or for the season, inboards are the only way to go.
 
I think your success or lack thereof, is directly proportional to the amount of maintenance and cost you are willing to tolerate. I have been a coastal Florida boater for 30 years. Our marina is full of I/O powered boats, but, all are dry stacked in the marina facilities, all are flushed when lifted out of the water and all are maintained by the marina according to the schedule they find works best for the type drive on the boat. I cannot tell you a single person who keeps an I/O in the water all the time.

All Bravo III drives are removed and service every 50 hours, other drives with less exposed stainless steel are serviced every 100 hours. One of the reasons for the accelerated service is that it only takes one monofilament line to wrap the prop and run into and cut the seal. If you don't catch the saltwater in the gear case early, you will be rebuilding or replacing the gear case.

The other thing to remember is that the i/o lower unit is a replaceable assembly and for one reason or another, about every 5-7 years, salt water i/o owners usually have to replace a lower unit about that frequently.

I am not a fan of i/o's and I wouldn't own one..........certainly not in saltwater.
 
Owned a 300 Dancer with twin 5.7 bravo threes for ten years. Always lift kept but salt water operated. Had to replace both transom assembly's at about year 7. There is a problem with that set up that allows salt build up in the transom assembly hose that slowly closes off the water intake. Beware
 
Owned a 300 Dancer with twin 5.7 bravo threes for ten years. Always lift kept but salt water operated. Had to replace both transom assembly's at about year 7. There is a problem with that set up that allows salt build up in the transom assembly hose that slowly closes off the water intake. Beware
Thanks fr8dog>
 
I think your success or lack thereof, is directly proportional to the amount of maintenance and cost you are willing to tolerate. I have been a coastal Florida boater for 30 years. Our marina is full of I/O powered boats, but, all are dry stacked in the marina facilities, all are flushed when lifted out of the water and all are maintained by the marina according to the schedule they find works best for the type drive on the boat. I cannot tell you a single person who keeps an I/O in the water all the time.

All Bravo III drives are removed and service every 50 hours, other drives with less exposed stainless steel are serviced every 100 hours. One of the reasons for the accelerated service is that it only takes one monofilament line to wrap the prop and run into and cut the seal. If you don't catch the saltwater in the gear case early, you will be rebuilding or replacing the gear case.

The other thing to remember is that the i/o lower unit is a replaceable assembly and for one reason or another, about every 5-7 years, salt water i/o owners usually have to replace a lower unit about that frequently.

I am not a fan of i/o's and I wouldn't own one..........certainly not in saltwater.
Thanks webster! Any difference with Volvo DPs?
 
I own a 1985 23'Cobalt that lived its first 30 years in the water in Long Beach, CA. Not on a lift, not dry stacked but in the water. For the first 10 years the Mercathode System did its job and there was not a spot anywhere on the lower unit. I made a fresh water flush kit for the boat so after each use the engine was flushed with fresh water and that is what sat in it.

We discovered too late that the Mercathode System quit and then we replaced drives. However, I only just replaced the Gimbal Housing 3 years ago. I/Os will be fine in salt but you just have to understand the perils and the preventative measures to make the equipment last.
 
I own a 1985 23'Cobalt that lived its first 30 years in the water in Long Beach, CA. Not on a lift, not dry stacked but in the water. For the first 10 years the Mercathode System did its job and there was not a spot anywhere on the lower unit. I made a fresh water flush kit for the boat so after each use the engine was flushed with fresh water and that is what sat in it.

We discovered too late that the Mercathode System quit and then we replaced drives. However, I only just replaced the Gimbal Housing 3 years ago. I/Os will be fine in salt but you just have to understand the perils and the preventative measures to make the equipment last.
Great information NorCal Boater. Thanks!
 
We discovered too late that the Mercathode System quit and then we replaced drives.

Would it be a good maintenance practice to invest in that silver/silver chloride probe thingy (that is a highly technical term!) and perform stray current or leak tests on our own boats? After reading all of these posts, and my dock neighbor just had his outdrives reconditioned and the Mercathode System fixed/replaced, it seems that it may be prudent. Thoughts?
 
I keep my 89 300DA with twin alpha gen I's in salt water for the season, May thru end of Nov. I'm in a wet slip, no lift. I find that marine growth is the biggest issue. I have Mercathodes that I check often, I also hang two zinc 'guppies' over the side and connect them to my engine blocks when the boat is going to sit for a few weeks. Zinc wear is just a part of boating IMO. I keep up with the maint. new water pumps every year, new zincs every year, check bellows and hoses etc. The only issue I have had is the port transom assembly has suffered some corrosion damage and will need to be replaced at some point. Not too bad for a 89 boat stored in the water seasonally it's entire life. Prior to me buying it, it was in brackish water with occasional trips into salt. My engines are both new in the last three years and are now fresh water cooled as any engine in salt water that is raw water cooled is a problem waiting to happen.
All that said, if I ever get another boat, it will have straight shafts, just less maint. to do.
 
Would it be a good maintenance practice to invest in that silver/silver chloride probe thingy (that is a highly technical term!) and perform stray current or leak tests on our own boats? After reading all of these posts, and my dock neighbor just had his outdrives reconditioned and the Mercathode System fixed/replaced, it seems that it may be prudent. Thoughts?
Absolutely....
 
We have a 2006 300 sundancer- been kept in warm salt water for the last 12 years, only time it’s on the dry is for servicing... tin merc 5.0 mpi with bravo 3’s. no issues other than standard maintenance. Have just moved from warm to colder.....
 
Bob,

First point I'd make is we don't know your location. Location is important because corrosion (the core issue and root cause) is a function of salinity and water temperature. It is no coincidence that higher salinity levels goes hand in hand with higher water temperatures. Frank Webster is correct in that in Florida with its longer season, warmer weather, and higher salinity levels will basically dissolve a sterndrive in five years. In the colder water of New England Atlantic and in the Pacific (as reported by NorCal) you get a different result. In our case, our original BIII is going into the water for the summer for its sixteenth season in the Atlantic. From a corrosion perspective salt water use is harsher than fresh water, but the effects can be mitigated by maintenance, manner of use and geography.

The second point is more critical; the whole concept of an i/o is flawed. This is an issue regardless of where and what kind of water they are used in. They are complicated and it is too easy to over stress the machinery. By over stress I mean there are many small user originated things that create excess stress on internal components that have a cumulative effect. Little things like starting the engine with the drive up, or not keeping the zincs up, or operating with the trim too high. Can you do these things? Yes. Do they have a long term negative effect? Also yes.

You really need to do a pro & con analysis to see if it is right for you, based on your circumstances. You might not have a choice, if so you have to come up with a mitigation plan. I wouldn't categorically rule another boat with sterndrives out, but I would certainly factor the downside into the equation.

Henry
 
My experiences, FWIW.

I boat in the Long Island Sound. Bravo III drive, closed cooling system with a through hull water intake. Boat has been moored in salt water from May to October / November for 12 years this year. I have had very little abnormal issues with my drive. It is removed and inspected at the end of each season, including with a bore scope.

From memory, I've had to do the following repairs: Replace bellows 1x or 2x (normal maintenance); replace gimbal bearing 1x, repair damage to the skeg (cause unknown), replace bearing carrier (this year), repair trim senders (3-4x). I had to have the engine coupler replaced, but that was not an outdrive-specific issue, per se.

Knock wood, I've had no issue with corrosion. I do monitor the anodes and of course replace them religiously. The most annoying thing is the trim senders going bad as I like to know the drive trim and use it for good performance. The biggest issue for me has been marine growth on the drive and props. I spend a good amount of time scrubbing barnacles of the props, but that's the same with any boat. It's actually easier with outdrives because it's right under the swim platform and can be done while snorkeling.

In speaking with my yard's new mechanic over the weekend, he was very pleasantly surprised my boat has a through hull intake and thought it might be aftermarket vs. factory installed. He feels that esp for Brave 3 drives, bringing cooling water through the tiny holes in the drive just causes problems from clogging due to salt and general stuff in the water. He wishes all outdrive boats through hull water intakes as that would reduce issues.

I think IO's certainly have more regular maintenance and more risk of bad stuff happening, but they do fill a valid place in boat design.

Vs. V-drives
  • More fuel efficient.
  • More compact
  • Generally better access to the engines for maintenance
  • Able to boat in skinny water (tilt the drive up)
Vs. Straight inboards
  • Can be more efficient - thrust is back vs. angled down
  • More compact layout. Moves the engine to the back of the boat for more interior room.
  • Able to boat in skinny water (tilt the drive up)
Vs. outboards
  • Clean transom / swim platform. You lose the ability to have a swim platform or carry a dingy on the transome with an OB.
  • Generally more low end power
  • Less costly to repower when necessary.
Outboards are fast becoming the design favorite in new boats because they are easy to work on and can be tilted out of the water. But I don't want one on my family boat because of the swim platform issue. We use our swim platform all season long.

Anyway, don't rule out a boat just because it has an outdrive. Understand the maintenance needs, and if buying used have it carefully inspected.
 

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