Engine water inlet valve - best procedure ?

[sarabande]

Coming from a twitchy background where contingency plans for big nuclear power stations and data centres have to be 100% effective, I am open to suggestions about the main engine sea water inlet valve.

The valve works smoothly (the previous owner was meticulous in maintenance) and the lever is easily and quickly accessible through the engine cover. My preference is for the valve to be OPEN only when the engine is in use, or likely to be in use. Is that a valid and practical preference, especially as it is planned that there will be some lengthy passages without use of engine ?

Then, to ensure that the engine is never started without the valve in the OPEN position, and that the valve is always SHUT when not in use, how about the following to help aged crew and also younger visiting sailing slaves ?


1 Attach engine key to a brightly-coloured tag on a short line with an eye in the free end

2 Make uncluttered clip point for key on engine cover

3 When key is not needed in the control panel, it lives on the clip on the cover

4 When engine is not required, the eye is placed on the lever of the valve in the SHUT position (length of line ensures it cannot be placed on lever in OPEN position), and key and tag secured on the cover

5 When key is needed in control panel in cockpit, the line and tag are removed from the lever and the valve lever is turned to OPEN.

6 Key then inserted into switch in control panel, and replaced onto SHUT valve when not in use.

7 Key in switch will have bright tag visible as an aide-memoire

( a spare engine key is kept securely elsewhere)


I can see one tiny gap in the procedure...


Oh PS, I am presently writing a boat Operations Manual to help when new crew are on board and to act as a reference guide for aged owner when fatigued. Hence the use of caps for OPEN and SHUT, and similar critical control positions.

 

[pvb]

I think it's unnecessarily complicated. By all means turn the valve off when the boat is unattended, but turning it on and off every time you use the engine isn't required. The engine won't suffer from having the valve open when it's switched off.

 

[duncan99210]

I only ever shut the engine inlet valve when leaving the boat unattended for more than a day or so. The likelihood of anything going wrong with a regularly inspected set of hoses versus the damage to be done if you run the engine with the valve shut is such that I think it better to do it that way. Unless you were to put a solenoid operated valve in place which only opens when the ignition is on, any system that relies on tokens or tags is subject to operator error.

 

[prv]

I never close the seacocks, except to exercise them every few months when I remember, to stop them seizing. If you're worried about the plumbing behind them failing, fix the plumbing.

Pete

 

[Spi D]

Fit a monitored valve (eg. http://trudesignplastics-com.s3.ama...uments/9/12254d66a9371c889aeaa6b85e9b7bb3.pdf), connect to control starting (like in-gear start protection)

And/or: Fit an Aqualarm Flow detector. When powered will sound whenever water is not flowing.
http://aqualarm.net/cooling-water-flow-c-2/

Alternatively may consider a solenoid valve, operated by turn of key.

 

[lydiamight]

I just had the engine start key on a short piece of line. The engine sea cock was the lever type and I just hooked the string over the sea cock lever when I closed it. Meant that I couldn't get to the engine key without opening the sea cock---simple and pretty fool proof.

 

[NormanS]

That takes me back to when I had a Folkboat with a hand start MD1. The exhaust didn't have an adequate swan neck, so I fitted a gate valve at the exhaust outlet, and used to hang the handle on it, so that there was no possibility of starting, without first opening the valve.

I only close the engine cooling inlet if I am leaving the boat for more than a day or two. I do the basic oil and water checks every day before starting the engine, so I suppose the seacock is part of the daily visual check.
Strange how I jump into the car, and never think to check anything.

 

[Tranona]

Modern engine panels do not have a key. don't understand the paranoia about shutting the valve every time the engine is not used. Like pete, leave them open all the time and just exercise them all on a regular basis. Downstream hoses are not under any pressure and are easy to check for security so chances of failure are close to zero. Apart from the attachment to the fitting most joints are above the waterline so failure would not result in water coming in. Checking the below waterline joints are easy when checking the valves.

 

[Poignard]

I just had the engine start key on a short piece of line. The engine sea cock was the lever type and I just hooked the string over the sea cock lever when I closed it. Meant that I couldn't get to the engine key without opening the sea cock---simple and pretty fool proof.

That's what I do. When the key isn't in the keyswitch, it's hanging on the seacock ( except for a couple of times when it fell into the bilge sump ).

 

[jac]

My view is what is the most likely emergency scenario with the seacock open / closed. Is it the hose failing causing flooding or is it suddenly needing the engine to avoid being set down on something and not being able to open it in time.
Secondly - what are the consequences. If the hose fails and you are aboard - you locate the leak - close the seacock and pump out. If the engine seacock is closed you either open it first then rush back and start engine - losing maybe 30 seconds ( which may be too late) or run with no water causing damage.

Seacock open if boat in use and to move from home mooring is my conclusion. Fit an emergency alarm if water detected in the bilge and automatic pump . Put wooden bungs attached to each seacock incase skin fitting itself fails.

 

[Kwik Decision]

I'm in the school of closing the engine inlet seacock only when leaving the boat for a significant period of time. It is part of our putting the boat to bed routine. I guess the main reason for doing so is to ensure the valve is exercised regularly, as the chance of the hose failing with nobody on board is vanishingly small.......

 

[prv]

don't understand the paranoia about shutting the valve every time the engine is not used.

I can only assume it comes from the days of lead and gutta-percha.

Pete

 

[vyv_cox]

I open the seacock in April and close it in October but we are on board pretty much the whole of that time. However, there have been times when after sailing in choppy conditions the water seemed to drain out of the strainer, the old type that attached to the seacock, and the pump would not prime when the engine was started. We then began to close the valve when sailing, which seemed to help. Since fitting a Vetus strainer above the waterline, with its reservoir of water, the problem no longer occurs and I leave the valve open.

 

[VicS]

Coming from a twitchy background where contingency plans for big nuclear power stations and data centres have to be 100% effective,

Cant you nick a "trapped key interlock system" from one of your nuclear power stations

 

[nigelmercier]

To me the question of the valve being open is easily answered by always checking for spluttering exhaust.

 

[Spi D]

To me the question of the valve being open is easily answered by always checking for spluttering exhaust.

But if you start the engine and let it run for as much as a 30 seconds before detecting lack of splutter and turning the engine off, the impeller most likely will be dead.

 

[Len Ingalls]

But if you start the engine and let it run for as much as a 30 seconds before detecting lack of splutter and turning the engine off, the impeller most likely will be dead.

If you are going to close the engine seacock, consider a Speedseal : http://www.speedseal.com/

 

[jwilson]

I'm in the school of closing the engine inlet seacock only when leaving the boat for a significant period of time. It is part of our putting the boat to bed routine. I guess the main reason for doing so is to ensure the valve is exercised regularly, as the chance of the hose failing with nobody on board is vanishingly small.......

I'm with you on this. On previous (trad long-keel) boat had two cockpit drain seacocks that could only be accessed by a long-armed chimpanzee who had already emptied the cockpit lockers. Funnily enough they stayed open for years on end.....

 

[lw395]

But if you start the engine and let it run for as much as a 30 seconds before detecting lack of splutter and turning the engine off, the impeller most likely will be dead.

Impellers have to be pretty dry to get destroyed, I reckon the exhaust hose might die first.
Many boats take a long time to show the water is turned off, as there's enough water in the exhaust to splutter for quite a while at low rpm.
I leave seacocks on in general, if they are going to fail, I expect they'll shear right off the hull. I do check the hoses more than once a year though....

 

[jac]

Impellers have to be pretty dry to get destroyed, I reckon the exhaust hose might die first.
Many boats take a long time to show the water is turned off, as there's enough water in the exhaust to splutter for quite a while at low rpm.
I leave seacocks on in general, if they are going to fail, I expect they'll shear right off the hull. I do check the hoses more than once a year though....

That's one advantage of operating the seacocks every time. You have to look at the things to find the handle and a quick visual inspection is better than nothing. You will at least spot something looking odd.