Leaking saildrive seal? Or what?

[arto]

I'm collecting roughly a bucketful of water a day in the bilges of my boat and the saildrive looks like the culprit by a process of elimination.

Could water be finding its way around the seal *without* it being obvious from a visual inspection of the saildrive? Viewed from above (i.e. from inside the boat) the seal looks to be intact and there's no obvious ingres of water.

The boat is a 2001 Dehler 36 with a Volvo 2030 and saildrive. There are relatively few potential leak sites below the waterline when the boat is at rest.

The four seacocks for the heads and galley all seem completely dry.

There is no leak from the log impellor.

I've drained and dried the bilges completely and can see a trickle appearing from the aft part of the boat - i.e. not from the keel bolts - but because of the inner moulding I can only be confident it's coming from somewhere aft.

That leaves the saildrive and the rudder. It's not the rudder which is at the extreme aft (and the bilges are dry between the rudder and the engine).

That leaves the saildrive. This looks completely dry from above. What I can't figure out is whether there could be any ingres of water that I can't see - and never having inspected the hull with the saildrive removed, I'm not sure how the whole thing fits together.

Failed saildrive seals seem to be pretty well unheard of, but are presumably possible or Volvo wouldn't recommend their replacement every 7 years. The saildrive was removed to gain access to the engine a couple of years ago and I guess it is possible that the seal was damaged or some dirt introduced at the time.

Any thoughts? My current plan is to have the boat lifted and to replace the saildrive seal but it's not a cheap exercise and the thought that I could be chasing a wild goose pains me.

 

[moondancer]

Re: Leaking saildrive seal? Or what?

Could it be where the saildrive bed is bonded to the hull? The important bit is the tube through which the saildrive leg goes through the hull. Where the saildrive bed joins the hull on the inside here has to be watertight.

 

[scottie]

Re: Leaking saildrive seal? Or what?

does the leak occur when engine is not running then check the cockpit drain pipes and exhaust pipe seacocks
if it occurs when engine is running then
check out the following first
anti syphon valve /pipe
end covers on heat exchanger
pipe to/from water pump
water inlet valve

 

[laserman2]

We had a leak in our boat fitted with MD2020 and 120sD sail drive.

Never thought the source of the leak was the sail drive seal as it had been replaced 2 years earlier.

We tested the water ingress and found it wash fresh not salt water.

WE then narrowed it down to the leak occuring when the boat was beating. Not when the engine was running in the upright position.

Next we realised that it must be coming from the fresh water tank. It was the inspection hatch seal that had gone.

You might want to try and trace the source further?

 

[arto]

Re: Leaking saildrive seal? Or what?

Thanks for the suggestions.

Leak is when engine is not running. The exhaust and cockpit drains both exit the hull above the waterline. The cooling water inlet is part of the saildrive.

Cheers

 

[arto]

Hi

Yes, I wondered about leaking water tanks - but this is salt water and is coming from the wrong end of the boat. Unfortunately.

Thanks.

 

[bigwow]

Re: Leaking saildrive seal? Or what?

Is the water coming from the pipe that goes from the seacock, on the saildrive, to the water pump. On mine the copper part of this pipe is only sealed with a rubber washer where it goes into the pump, It might also be worth just giving the ring of nuts around the saildrive seal a slight tweak, with a spanner.

 

[starboard]

How about checking around the keel bolts!!

Paul.

 

[arto]

[ QUOTE ]
How about checking around the keel bolts!!

Paul.

[/ QUOTE ]

My first thought (not a happy one) was that it might be the keel bolts. But having dried the bilge and checked all of them, I'm confident that isn't where the water is coming in.

Right now, I think PUMAOFPAG's idea is the most plausible - that there might be some kind of leak between the saildrive bed and the rest of the hull. But that's not an easy one to check without lifting the boat or cutting some access holes in the inner moulding.

 

[theotter]

May I suggest you try running the engine hard in reverse and see if that increases the leak. This will tend to 'lift' the engine/saildrive and if there is a engine bed bonding problem (God forbid), it would tend to open the gap so to speak and increase the leak rate. It might also help give some indicators if it is a diaphram problem which I doubt if you haven't had this problem over the last 2 years. Should be simple enough to see if the diaphram is leaking...stuff loads of kitchen towel around it that should soon indicate a leak. Good luck!

 

[arto]

[ QUOTE ]
May I suggest you try running the engine hard in reverse and see if that increases the leak. This will tend to 'lift' the engine/saildrive and if there is a engine bed bonding problem (God forbid), it would tend to open the gap so to speak and increase the leak rate. It might also help give some indicators if it is a diaphram problem which I doubt if you haven't had this problem over the last 2 years. Should be simple enough to see if the diaphram is leaking...stuff loads of kitchen towel around it that should soon indicate a leak. Good luck!

[/ QUOTE ]

Useful, thanks.

But am I right in thinking that any leak from the diaphragm will be visible from above? So that if I fail to detect any water, then the saildrive bed/hull bond is the problem?

 

[Gin]

How about getting some coloured powder, e.g.water colour paint and sprinkle it liberally around each potential leak site one at a time. Discolouration of the bilge water will indicate when you've found the culprit?

 

[steve_cronin]

Where does the relief valve from your anti-syphon loop run to?

If left to run into the bilge like the majority, then that could be your problem especially if you've recently replaced the impellor. It can normally be routed to a spigot on the silencer.

Do you have a sugar scoop flange? If that has been damaged then water can get in through the transom/hull joint. If it's fresh water - taste it - then that will be your problem.

Finally, being a Dehler, are you certain that the Water Ballast system isn't leaking?


I would doubt the main leg seal as, if you've completely dried that right down to using kitchen roll to mop up every last drop, then a leak of that rate would be immediately visible onto the rubber around the grey metal sealing ring.

Steve Cronin

 

[widgeon]

I had similar symtoms which I tracked to the Volvo exhaust water trap. The lower stainless steel end cap had developed a pin hole in the weld around the pipe connection that allowed water to dribble out when the engine was not running. (When the engine was running it must have been leaking exhaust gas into the aft cabin, but luckily we hadn't found that out the hard way!) The result was a similar trickle from the area below/aft of the engine (Volvo 2020) around the saildrive as the water in the trap darined away. It took some time to find the actual source.

 

[arto]

Just in case anyone is interested...

Finally got to the bottom of this (literally).

Lifted the boat today. Removed the outer (more or less cosmetic) seal from the saildrive leg and make sure the bilge was full of water. Dried and cleaneed around the saildrive leg and established there was a small trickle of water from an almost invisible gap between the hull and the cylinder shaped inner moulding that the saildrive sits in - right at the base where the inner moulding is attached to the hull. Not an impressive piece of engineering by Dehler on the face of it, but I don't know what might have happened to the boat before it belonged to me.

Looks fixable, at least that's what the fine folks at Gosport Boat Yard tell me, and it avoids the expense of replacing the saildrive gasket which always seemed an unlikely culprit.

Thanks to all of you who proposed possible explanations. Now I'm hoping the fix will be good and Ill have a dry bildge for the rest of the season.

 

[moondancer]

Re: Leaking saildrive seal? Or what?

Bingo. Guessed right!

 

[arto]

Re: Leaking saildrive seal? Or what?

Indeed. And once the boat was out of the water, it became pretty obvious it couldn't be the saildrive diaphragm as I had water leaking *out* of the boat but the level inside the boat was not high enough to reach it.

Thanks.

 

[Valkyrie Dehler 36]

I'm collecting roughly a bucketful of water a day in the bilges of my boat and the saildrive looks like the culprit by a process of elimination.

Could water be finding its way around the seal *without* it being obvious from a visual inspection of the saildrive? Viewed from above (i.e. from inside the boat) the seal looks to be intact and there's no obvious ingres of water.

The boat is a 2001 Dehler 36 with a Volvo 2030 and saildrive. There are relatively few potential leak sites below the waterline when the boat is at rest.

The four seacocks for the heads and galley all seem completely dry.

There is no leak from the log impellor.

I've drained and dried the bilges completely and can see a trickle appearing from the aft part of the boat - i.e. not from the keel bolts - but because of the inner moulding I can only be confident it's coming from somewhere aft.

That leaves the saildrive and the rudder. It's not the rudder which is at the extreme aft (and the bilges are dry between the rudder and the engine).

That leaves the saildrive. This looks completely dry from above. What I can't figure out is whether there could be any ingres of water that I can't see - and never having inspected the hull with the saildrive removed, I'm not sure how the whole thing fits together.

Failed saildrive seals seem to be pretty well unheard of, but are presumably possible or Volvo wouldn't recommend their replacement every 7 years. The saildrive was removed to gain access to the engine a couple of years ago and I guess it is possible that the seal was damaged or some dirt introduced at the time.

Any thoughts? My current plan is to have the boat lifted and to replace the saildrive seal but it's not a cheap exercise and the thought that I could be chasing a wild goose pains me.

This is late and off direct subject but I own a 2003 Dehler 36 and am planning to replace the Volvo diaphragm sail drive seal this spring. Can you advise if there is enough clearance to remove the saildrive from the engine (bringing up through the tunnel) without removing the propeller shaft at the bottom of the drive? With the backward facing engine there is not much room to slide the engine back into the aft berth area and then tilt the drive as Volvo instructions suggest. Thanks!

 

[SaltyC]

Not Dehler but assume most manufacturers mountings are fairly standard. I had a VP 2020 with 120s saildrive, the instructions were to move engine forward to disengage engine and saildrive. The saildrive then lifted out, tilting aft as you lift. It was necessary to remove the propllor but not the shaft to remove.

 

[Tranona]

Not familiar with your specific installation, but it is normal to have to remove the shaft. Makea sense anyway as it gives an opportunity to replace the lower seals as well as completely drain the leg.