Can I leave my outdrive up?

I've got a Volvo Penta AQAD41A diesel running a Duoprop 290 outdrive (1987 vintage). In order to combat very serious galvanic corrosion problems on the props, I've been advised by an expert to hang a zinc "fish" from the props. In order to easily attach and detach the fish, though, it is desirable to leave the outdrive in the extreme (beach/trailering) up position while the boat is sitting in the pen. Since my boat is permanently penned, this means the outdrive is in the up position essentially permanently (except when we go out for a run).

Is this a problem? Does it have any consequences for the hydraulics?

Jeff

Re: Can I leave my outdrive up?

Keep the drives down. If you keep them all the way up you're permanently stretching the bellows and also providing more surface area for 'critters' to grow. Barnacles are sharp (I assume you slip in salt water).

Why do you need additional zincs? Aren't the ones you already have in good shape? Or, is there an issue with 'power leakage' from your boat, or a neighbor's boat, or dockside power? When did the corrosion issue start?

If you can't find the problem and are compelled to add zincs, I don't see any reason you can't hang them from the BOAT, very close to the props. It will serve the same purpose and be easy to retrieve them before you set out.

My .02

Re: Can I leave my outdrive up?

Thanks very much for those comments. Much appreciated! Local advice was that it was fine to leave the drive up, and in fact was an advantage because it unloaded the hydraulic rams. Your points, however, make a lot of sense.

I won't bore you with the details of why I need to hang a "fish" over the props - other than to note briefly that Volvo now make props that contain hub materials that prevent the blades from making electrical connection with the shaft. My prop blades were, in consequence, simply melting away over weeks/months, despite my boat being otherwise very well protected.

I hired a galvanic corrosion expert (his day job is as an electrical/diesel submarine engineer who tells me he's spent a total of 14 years underwater during his career!). His solution was to hang the "fish" near the props and electrically connect the "fish" to the blades of the props with a couple of s/s clips.

So, that's the problem: attaching and detaching the clips to the blades. Easy if the drive is normally left in the extreme up position, but very awkward and irritating if it needs to be left down.

Jeff

Re: Can I leave my outdrive up?

Have you contacted Volvo w your issue? Maybe they have a kit or an update to address the problem. Might it be easier, but yes, expensive, to switch props to some that make connection ? I am not famaliar with a -zinc fish- or how its attached, I sure as heck would be afraid of forgeting about it sometime and putting it in gear, You know it would sound less then pretty But is there a reason you cant lift the drive , put it on-the fish-then lower the drive again, then to remove it ,could it be attached to a line so it could just be pulled away Or you would have to lift the drive again?

Re: Can I leave my outdrive up?

Had a friend with that problem.He bought a BIG zink plate and hung it next to the props.Itr slowed it down a lot.
The up position is for trailering.Up will allow lots of stuff to grow in the cracks and crevises of the bellows.J

Re: Can I leave my outdrive up?

skipjack27 said:

I've got a Volvo Penta AQAD41A diesel running a Duoprop 290 outdrive (1987 vintage). In order to combat very serious galvanic corrosion problems on the props, I've been advised by an expert to hang a zinc "fish" from the props. In order to easily attach and detach the fish, though, it is desirable to leave the outdrive in the extreme (beach/trailering) up position while the boat is sitting in the pen. Since my boat is permanently penned, this means the outdrive is in the up position essentially permanently (except when we go out for a run).

Is this a problem? Does it have any consequences for the hydraulics?

Jeff

Click to expand...

Not a real problem but down is btter. Less stress on the bellows.