Help! Excalibur II is taking on water!

[ExcaliburII]

To set the scene: for the last ten years or so of happy ownership, Excalibur II has been almost completely watertight. OK, a bit of rainwater finds its way into the bilge now and again, so there's always a litre or two sloshing about that the pumps can't pick up, but that's all.

Now, a couple of weeks ago, we left her in the marina after a problem-free day out and went home. I didn't check the bilges when we left, but everything was normal during the morning when I did the usual pre-start visual check of the oily bits. As luck would have it we were going out again the following day, but on arrival the cabin floor was awash and the water level in the engine room was up to the main bearers. So, we have instantly gone from watertight to taking on a couple of hundred litres in maybe 12 to 18 hours. Quick change of plan - left SWMBO in charge of the bilge pumps and I went straight back home to fetch the trailer. So the immediate crisis was fairly easily averted, but the problem now is to fix the leak.

I've taken the drive unit off twice now in the last week and fitted new seals and a shift cable gaiter as this was showing signs of very minor seepage. The main bellows was perfect so I cleaned and refitted that with bellows adhesive as per the book. On the second relaunch today, this time with the bilge area completely drained beforehand, I can now see a fine trickle of water dribbling down the inside of the transom below the bottom of the drive unit mounting plate.

So, a couple of questions to the learned elders of the forum: What is the next most likely cause of leakage on an Alpha 1 drive after the bellows and shift cable gaiter? I see from the parts diagram that there is a seal around the exhaust pipe - does anyone know if this is prone to failure and, if so, given that the exhaust is below the water level would that allow water into the boat? The other penetration in this area would appear to be for the hydraulic lines to the trim cylinders, but I can't see how they are sealed. Does anyone on here know? Or is the problem more likely to be the seal between the plate and the transom itself? (It's not loose, btw )

Clearly, the final solution is to take the drive off, lift the engine out of the boat, take the transom shield to bits, and reassemble everything with new seals everywhere, but I don't have the necessary heavy lifting equipment available, so I'm kind of working up to that in stages !

Any suggestions?

 

[carlton]

Sounds like a bellows problem. Did you change all three? (Shift/Universal joint/Exhaust)

Parts 13 and 19 -U.J. and Exhaust.

Part 26 - Shift

 

[oldgit]

Sounds like a bellows problem. Did you change all three? (Shift/Universal joint/Exhaust)

Is the transom plate submerged at all and is there a grease nipple on the steeriing yoke shaft.
Not 100% on mercruiser but my volvo has a grease nipple which fills the steering shaft not only to lubricate it but also prevent water ingress if shaft seal are worn !

 

[MarieK]

Are you certain it is the drive? Any thru hull fittings such as transducers or anode bolts that could be letting water in?

 

[omega2]

no wish to pour petrol on the fire but I have heard/seen the through bolts on the transom shield rusting away and failing, sounds like the lot needs to come off, and a refit.

 

[ExcaliburII]

Thanks to all for replies so far.

Carlton - I fitted a new shift cable bellows because the flange it fits on looked a bit corroded and there was wet silt inside it, indicating it had been seeping a bit. Flange cleaned up and new bellows fitted with adhesive/sealer, so I'm confident that's not still leaking. As I said, the main bellows was perfect, so I cleaned up the flange and bellows and refitted it. Before I took it off, it was clean and dry inside, so no indication it had been leaking. I don't use a bellows on the exhaust; I fitted a straight tube years ago to avoid possible problems with the exhaust bellows ballooning under pressure and pushing the main bellows into the U/J, causing failure. The exhaust tube doesn't seal to the drive unit and it's fully submerged, so any leaks there won't make any difference.

Oldgit - steering nipple is fully greased and no discernible play in the bearing, so I don't think it's that. If it were the source, I would expect to see water around the steering arm inside, and that area looks dry, thanks.

MarieK - the only through hull tx is my paddle log, and that is bone dry, so not the problem. No separate anode bolts anywhere, and the boat is fitted with a Mercathode system so, thankfully, not much generally in the way of corrosion problems. Not that I've found so far, anyway . . .

Omega2 - I haven't actually taken a spanner to any of the through bolts, and they don't look corroded, but that's an interesting one I wasn't aware of. Presumably, if the bolts rust and fail, they will either fall out wholesale and the water pours in through the hole (which is not happening here), or they will stretch as they weaken and allow the transom plate to loosen and leak. As you say, I have a horrible feeling I'm going to need to find some heavy lifting kit and psych myself up for an engine out job.