Water Intake on Hanse 350 Saildrive.

[andythefiddler]

Hi All,

I'm a little concerned that I have never cleaned the raw cooling water system on my Hanse 350.

I looked last year at cleaning the system out, but now think, lets go right back to basics, lets look at the water coming in, that's where there could be gremlins growing etc.

It has never shown it is overheating but I'd like to ensure all is OK before then.

Does anyone have a diagram - or can point me to one - of how the water gets into the system through the sail drive?

That's all really, seems like a simple query but I am sure (as ever) it isn't.

Andy

 

[Tranona]

It just comes in through the slots and up the leg in a gallery to the stopcock in the housing inside the boat. It is of course possible for something to decide to bind a home in the internal gallery but rare. The growths are usually around the slots at the bottom of the housing. If you are getting good flow then nothing to do, but worth checking the slots when you lift out for antifouling.

 

[tross]

Water comes in through the slots as Tranona says but there is a square hole underneath by the oil drain plug which is the main water gallery. I think the slots are there to provide water when the boat is in reverse - could be wrong

 

[ashtead]

You don’t say the year of your Hanse but why do you consider it needs cleaning -is this because the saildrive is being removed but just curious as to need to clean if no barnacles around the drive slots?

 

[Neeves]

I don't know the Hanse 350 sail drive, it would be unusual not to be a standard unit.

We have Volvo saidrives. There are slots either side of the sail drive, matching slots. Push a screwdriver through one slot and ream through to the slot on the other side.

There is an intake at the base of the unit use the same screwdriver to clear anything. You need space to ram the screwdriver vertically up inside.

You have now cleared any or most growth. If you had growth you will have felt the growth as you inserted the screwdriver.

This next part really needs 2 people.

You can now back flush the unit. At the engine the raw seawater enters at a stopcock on the sail drive. Take off the rubber hose connected on the inside of the yacht, at the top of the sail drive. Replace the 'engine' hose with a freshwater hose from the marina. Turn on freshwater hose and flush the sail drive. You need 2 people in case your freshwater connection is inadequate - you don't need to flood the interior.

If its a new sail drive or if calcareous growth is not severe where you are moored this may all be unnecessary - if calcareous growth is severe its worth doing and its not difficult.

If you do all this - check from the exterior if there are any loosed bits of shell too big to be flushed out. Attack with the screw driver, again and break up.

Now Hanse sail drive installations may be totally different to our Volvos - in which case apologies.

This is our sail drive, it and the prop are coated with PropSpeed.

The three slots on the sail drive are matched on the other side, simply ream right through. There is another entry for sea water at the base of the sail drive right at the bottom and forward of the oil seal), which you can just see a little bit forward of the taped anode (its a flat screw drive 'bolt'). Again ream from below. A screw driver works for reaming or simply a steel rod. We use a roller handle and straightened out the rod as it reams right up to the top of the saildrive.


Jonathan

 

[Skylark]

I have a Yanmar sail drive and I’ve cleaned/flushed the raw water system just once, at about 5 years. Job done immediately prior to season launch. Wrap bottom of leg with cling film. Pour brick cleaner into strainer having first blocked the engine feed hole. Leave for about half an hour, then remove cling film and catch fluid and debris in a bucket. Flush, clean-up and launch.

 

[johnalison]

I know of one person who suffered a blockage that turned out to be mussels growing in his saildrive, but other than clearing the holes on my Volvo unit I don't do anything more and it seems fine after 22 years.

 

[andythefiddler]

Thanks all.

I take all the points on board and will proceed accordingly, with great care.

 

[ashtead]

Talking of saildrive I heard that Volvo had recently changed the metal in saildrive anodes leading to a mismatch between hull and saildrive anodes. I mention in case anode replacement is also a topic of interest on saildrive. Welcome views on issues this might cause though.

 

[Tranona]

Yes, aluminium anodes are becoming more common for all sorts of reasons. Most boats with saildrives don't have any other anodes except if they have folding/feathering propellers and I am not sure whether it is necessary to change these to aluminium.

 

[ashtead]

I gather due to zinc crisis but would not wish to stray into reasons .