Sail drive leak - options?

[PabloPicasso]

Isn't it amazing, I'm learning that their is loads more to worry about than I ever imagined. Surely if there was any leak below the waterline the 'weep' of water ingress would quickly flood the boat?

 

[Interlude]

I think I saw that this is a Yanmar? SD20???

How old is it and does it live in the water all year around? Any interactions with rocks etc?

I searched some time ago for seal failures and the only reported failures then were from a cat that had gone on the rocks. Any clarification appreciated.

 

[saxonpirate]

Isn't it amazing, I'm learning that their is loads more to worry about than I ever imagined. Surely if there was any leak below the waterline the 'weep' of water ingress would quickly flood the boat?

I wouldn't say its a worry, just something to be aware of and checked. Unlike a traditional engine bed structure that is bonded into a hull on all sides and can be physically seen, the saildrive bed moulding can only be laminated on its outside face and needs to be faultless. Regarding water ingress, because the bed moulding is hollow it will trap water if there's been a failing of the aperture bonding. The only time you'll get to know this is if you get an unexplained trickle/dribble of water coming from your engine bay area... and your thinking "where the hell is that coming from". As we all know... water (especially under pressure) will always find a way to escape if there is one. As for quickly flooding a boat, unless there's a major structural failure... that won't happen. I originally mentioned the bonding issue to the OP as something to check while undertaking a seal change because I've personally repaired four yachts where the aperture bonding had failed, so my comment is based on actual hands on experience, not hearsay.

Personally, I quite like the saildrive concept. I fitted a Volvo 110 S Drive when they first came out one to one of my own boats. The idea undoubtedly saves a lot of time on an engine installation compared to fitting a traditional prop drive, and if installed properly should give no problems whatsoever. So, no need to "worry" just be aware that like all things on our boats (especially below the waterline) checking and maintenance is essential for piece of mind afloat.

 

[Mrnotming]

Thanks for the acknowledgment Saxonpirate, yes it did happen and you were most helpful in helping me reach the correct diagnosis, i.e. the bed moulding joint strained at the aperature had caused seawater(tasted) to appear at the engine mounting bolts.Drilling the holes mentioned in earlier post revealed a goodly flow of water entering the hull, quite separate to any question of a diaphram leak.In fact the diaphram seemed as new when removed, boat craned out and stored ashore for the work.However there was corrosion of plate components needing re-coating so it was great to have the yard epoxy expert do the aperature re-sealing,whilst I looked after the mechanical work.A person who is used to motorbike or car maintenance of the more involved kind should be capable if not rushed, to undertake seal renewal, there are several PBO articles available to download which adequately explain the procedure.Use a camera at each step, store components in labelled containers, buy all the gear and sealants in advance as they are specialised, from somewhere like Keypart or Volspec( no connection) and use a torque wrench to achieve correct tensions.Seven years seems to arrive much too quickly!