Engine raw water seacock - is it more important or vulnerable than any other?

I always close all seacocks (except cockpit drains) if leaving the yacht for a couple of weeks or more. Then tie a string on the morse lever to remind myself the engine raw water intake is shut. This seems such a simple precaution, which takes not 2 minutes, that it is hardly a matter of "weighing up the risks".

If you are not going to bother, I'm tempted to wonder why fit sea-cocks in the first place? In any case, even if they are there, chances are they will have seized or broken if you don't exercise them from time to time.

Incidentally, a few years ago a yacht sank in a marina where I was based, as a result of a failed hose clip on a seacock that had been left open. Oozing diesel then made a terrible mess. So it does happen.

Well that’s not going to work - why would a guest or mechanic be a mind reader and know whet the magic string meant?
 
Well that’s not going to work - why would a guest or mechanic be a mind reader and know whet the magic string meant?
How would they start the engine if I wasn't present? The key is on my ring. They would have to break into the cabin, find and turn on the starter motor battery, hotwire the engine.

Do you have guests like that?
 
Well that’s not going to work - why would a guest or mechanic be a mind reader and know whet the magic string meant?
P.S. That sounds like an elementary test that your mechanic is not a complete idiot. Does he check the cooling water is on, before starting the engine?
 
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If you are not going to bother, I'm tempted to wonder why fit sea-cocks in the first place?

For the same reason as the stopcock in my house - so that I can close it before opening up the system for whatever reason. But I don't shut off my house's water supply every time I go away for the weekend - or even, like some boatowners do, every time I finish filling the sink or flushing the loo. And my domestic hot and cold water system is actually under significant pressure, unlike boat seawater plumbing, and has joints inside walls and floors that can't be inspected.

Pete
 
If your engine is below the waterline or, more precisely, the water injection point into the exhaust is then, as I found on a previous boat, the only thing between a flooded engine (or boat) is the impeller in the pump.

Such an engine is installed incorrectly and contrary to the manufacturer's instructions. The solution (as you point out) is a siphon break, which is not an optional "alleviation" but a mandatory part of the system.

Same with toilets; the manual describes how to install a safe and correctly functioning system, but some people ignore the design, build a dangerous partly-working installation, and then work around its failings with manual valves.

Incorrect installations like this ought to fail survey; I wonder how often they do?

Pete
 
For the same reason as the stopcock in my house - so that I can close it before opening up the system for whatever reason. But I don't shut off my house's water supply every time I go away for the weekend - or even, like some boatowners do, every time I finish filling the sink or flushing the loo. And my domestic hot and cold water system is actually under significant pressure, unlike boat seawater plumbing, and has joints inside walls and floors that can't be inspected.
Seems like we might have to agree to disagree. The inlet stopcock to my flat is right to hand. If I'm going away for a couple of weeks (not just a weekend), why not turn off the water supply - the work of seconds.

My upstairs neighbour didn't. We first noticed when water dripped through our lighting. His front door had to be smashed in for access, the flood-water (from a split water tank) poured out and down the stair-well like a horror movie. All his flooring was ruined. My insurance company sued him for replacement of our electrics. He wasn't insured, either. Subsequently the wrecked flat was sold for £40,000 below the usual market price. All for neglect of 15 seconds effort.

But, hey, it's a free country, everyone to their own.
 
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I have an above the waterline inlet water filter, so even if I remove a hose from the engine, no water floods in. I fitted this filter when I re-engine to replace the all in one filter and seacock which was not easy to get at. I do leave the engine seacock open after an incident on my previous boat when I was in a hurry and forgot to open it - it certainly makes you able to change an impellor very quickly as you get pushed nearly aground by the tide. I only noticed it as I suddenly realised that the engine was noisier than usual, I didn't have an overheat alarm.
 
I close all (six) seacocks when I leave the boat, open them all when I arrive next time. Takes one minute in total, which is 0.2% of the time spent preparing the boat for a sail - whether out for the day or off for a month - and then tidying up and putting it away again.

No point in getting all ideological - just put on your checklist whatever makes you happy, then just do all the items in turn without having to mither.
 
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