Sail Drive Mystery

[Carmelo]

I have a problem on my Lagoon 400 that has me and my engineer stumped.

It has been out of the water for antifouling. I changed the oil in the sail drives (yanmar SD50s) and the engineer changed the sail drive zincs (requiring removal of the propellers). The props are folding 3 blades - flexofold I think but not sure what brand Lagoon supply. When the boat went back in the water after reversing a few yards I immediately lost all drive - first in one engine then the other. I think this happened when i went from reverse to fwd.

I assume the cause must be incorrect installation of the props but the engineer insists this is not possible and he has fitted many before. There does not appear to be any problem with the sail drives.

Any suggestions/experience of this issue? Are there any common mistakes when refitting folding props on sail drives that could cause this?

Thanks

[Cotemar]

Check the sail drive oil again.

When fill mine it looks full until I wait a day or two to run the drive then look at the oil level and it is way way down

[Carmelo]

Cotemar

Thanks for the suggestion. The level was ok when i filled it yesterday and today it was still ok before the boat was launched and still ok after the attempt to leave the pontoon. I carefully measured the amount of oil that went in per the manual so am confident it was right - and I'm unlikely to have got it wrong in both engines.

Also, if the level is low would this result in no propulsion? I assume more likely a problem later on?

Any other ideas? Is it possible to fit the folding props wrongly in such a way that they stay on but give no drive?

Carmelo

[Ram]

[QUOTE=Carmelo;934013


Any other ideas? Is it possible to fit the folding props wrongly in such a way that they stay on but give no drive?

Carmelo[/QUOTE]

This sounds likely, what eles could it be? Good luck

[Cotemar]

Tie the boat to the dock extra tight.
1) Put port engine in forward
2) Walk down the stb. sugar scoop and look at the port prop to see if it opens. Should be able to see it from that location and angle.
3) repeat this step in reverse to see if props are opening.
4) If no thrust then the props are lockup somehow.

Do your props have gears on the blade roots?

[Tellie]

Are the props still there?
Sounds like a silly question, but props on sail drives that have recently been removed and replaced have been known to come off when dropped in reverse.

[Carmelo]

the port prop is definitely still there (and folded) as I can see it from the pontoon. Not sure about the starboard one as the light was going and the water is very murky. I could rev the engines hard in gear while on the pontoon and there was no thrust at all.

Cotemar: not sure what you mean by "gears on the blade roots"?

Am i right in thinking if the props have been wrongly fitted I should still be able to see the hubs turning when in gear? Ie its not possible for the hubs to be on the spline and not turn if the engine is in gear and the sail drive is functioning?

[Cotemar]

If the port prop is still there and folded and giving no thrust forward or aft then the blades are locked (installed improperly).
Try and open the blades with a boat hook. They should open very easily.

[Carmelo]

saildrive.jpg Views: 142 Size: 26.9 KB ID: 40148" style="margin: 2px" />

My cat had to come back out of the water today and the mystery was instantly solved - see photo. Seems that the bolts holding together the bottom of the drives were undone when the anodes were changed. Although I don't understand how this happened as those bolts don't need to be undone to change the anode.

Thanks for the help/suggestions.

[GlobalHopper]

You really need to check the oil to make sure you didn't get any water/salt inside.
If it's milky color you need to flush it and add fresh oil.

[Carmelo]

Globalhopper

Yes, thanks - both drives were flushed and refilled with new oil. I'm still baffled as to how it could have happened as there are two bolts holding the loose piece you can see in the photo in place which I think did not need to be undone to change the anode. They must have been undone on both drives.

Carmelo

[Cotemar]

Carmelo,

You have two anodes. One on the back of the prop and one on the back of the sail drive. The anode on the back of the sail drive is missing the bolts.

It backed out along with its mounting base and then the lower gear lost it contact with the vertical shaft gear.

Make sure that drain/replace the saildrive oil again as the bottom of the sail drive now has water in it

[Cotemar]

Did they do that on both sail drive?

[Carmelo]

yes, both drives.

the bolts that were missing are the ones between the main sail drive leg and the plate behind the anode behind the prop. to change the anode you should not need to undo them at all. i can't figure out how it happened - something to do with switching from old style anode that requires removal of the prop to the new yanmar style that can be fitted in the water without removal of prop.

I'm in China so communication with the engineers is not easy, especially when things don't go smoothly!

[Cotemar]

漢字/汉字
I understand completely. This is all DYI, so you may want to do it yourself next time.