Saildrive

[sailaboutvic]

Here a question for all the people who are good at inventing some thing out of nothing .
I need to do a vacuum and suction test on my sail drive .
Here the thing I have no gauge and no way of getting any ,
The pressure test I can do by fitting my dinghy foot pump to the oil filler then use soppy water around the seals and bearing housing that should work .
It's the suction is where I need suggestions with .
For them who worked on saildrive before you know what I mean .
Thanks

 

[Skipper_Christoph]

Our dinghy foot pump has two holes. One for pressure, the other for suction. Maybe it is as simple as swapping the hose to the other hole?

 

[sailaboutvic]

Our dinghy foot pump has two holes. One for pressure, the other for suction. Maybe it is as simple as swapping the hose to the other hole?

Great idea but I would need a gauge to work , good thinking tho

 

[pvb]

Great idea but I would need a gauge to work , good thinking tho

Depending on how much vacuum you want to apply, you could make a simple vacuum gauge with a piece of clear pipe dipped into a fairly dense liquid. As you apply the vacuum to the top of the pipe, the liquid would be sucked up. Then wait to see if it drops, indicating that air is entering the saildrive.

 

[RichardS]

As PVB says, it depends upon how much suction you wish to apply, although the method below will generate about negative 13 psi which is almost like deep space.

My frequently-used method (as recently as an hour ago in my garage on a gas valve!) is to attach some tubing to the vessel. If it has a spigot it's simple but, even with a female thread, if you find a close fitting plastic pipe you can screw it into the threaded aperture and it will seal well enough. Then suck on the pipe and keep sucking until you can feel the vacuum trying to pull your tongue down the pipe.

Then just wait with your tongue stuck on the end of the pipe.

After, a few minutes you will know whether the vacuum is remaining constant or whether it's slipping away.

Richard

 

[Ian_Rob]

Deleted

 

[sailaboutvic]

As PVB says, it depends upon how much suction you wish to apply, although the method below will generate about negative 13 psi which is almost like deep space.

My frequently-used method (as recently as an hour ago in my garage on a gas valve!) is to attach some tubing to the vessel. If it has a spigot it's simple but, even with a female thread, if you find a close fitting plastic pipe you can screw it into the threaded aperture and it will seal well enough. Then suck on the pipe and keep sucking until you can feel the vacuum trying to pull your tongue down the pipe.

Then just wait with your tongue stuck on the end of the pipe.

After, a few minutes you will know whether the vacuum is remaining constant or whether it's slipping away.

Richard

Will that work in a saildrive I guess there be lots of sucking to do .

 

[RichardS]

Will that work in a saildrive I guess there be lots of sucking to do .

It depends how much air space there is above the oil. If there's too much air space, you could overfill the oil to leave a smaller air space and then suck/Pela out the excess oil once you've finished the test.

Richard

 

[sailaboutvic]

It depends how much air space there is above the oil. If there's too much air space, you could overfill the oil to leave a smaller air space and then suck/Pela out the excess oil once you've finished the test.

Richard

Richard check PM or your email

 

[Yngmar]

Next time you're somewhere with a postal address, get a Mityvac kit and keep it on the boat: Mityvac MV8500 Silverline Vac/Pres Metal Pump Kit: Amazon.co.uk: Car & Motorbike

It's a small hand pump that can be switched between vacuum and pressure, it's got a gauge (for both) and comes with a bunch of useful bits like hoses and containers for pumping fluids and those colourful rubber nubbins that let you achieve a seal between the hose and just about any fitting by simply stuffing them together.

Meanwhile, try not to vape too much gear oil! ;-)

 

[Rappey]

Then just wait with your tongue stuck on the end of the pipe.

You use the same method I use for airtightness ? ?

 

[sailaboutvic]

Next time you're somewhere with a postal address, get a Mityvac kit and keep it on the boat: Mityvac MV8500 Silverline Vac/Pres Metal Pump Kit: Amazon.co.uk: Car & Motorbike

It's a small hand pump that can be switched between vacuum and pressure, it's got a gauge (for both) and comes with a bunch of useful bits like hoses and containers for pumping fluids and those colourful rubber nubbins that let you achieve a seal between the hose and just about any fitting by simply stuffing them together.

Meanwhile, try not to vape too much gear oil! ;-)

Now you tell me
We have a real problem , can't real use the engine now , we pump out oil and water mix last night and topped up , left it on the min level . To day only use the engine to move of anchor and re anchor , level gone from min to Max in less then say 15 mins .
The worry now is the seal has total failed and the box will fill up with sea water , we have 60 miles to sail to get haul out and with very little wind and on our nose it getting a bit stress ful .
I'm convinced the problem is too much slack play in the shaft .

 

[RichardS]

I'm convinced the problem is too much slack play in the shaft .

Hi Vic. I saw your post about slow sailing and noticed that you might have decided what the problem was but I thought that you were satisfied with the play in the shaft?

Richard