How to Ruin a Pump Impellor thru' Automatic Actions

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bdsweeting

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How to Ruin a Pump Impellor thru\' Automatic Actions

Took the boat out this evening to do a bit of fishing and to blow away the days cobwebs.

Did the usual things on arriving at the boat...
Cockpit cover off and stowed,
battery switch to ON,
lift floorboard and turn seacock handle,
prime engine, preheat and start.

Give it several minutes to warm up and then untie the warps and leave the pontoon. A short time afterwards I could smell hot rubber !!!
Lift the engine cover to see the hoses melting off the sea water pump, oh sh*t!

Luckily I was still inside the harbour so headed to the nearest pontoon and shutdown the engine, then I tied off again.

The pump inlet hose had overheated and split but there was hardly any water coming out of the split which confused me somewhat.

Checked the seacock and found it closed, hence the fried impellor.

Thinking back over my routine this evening i realised that i must have left the seacock OPEN when leaving the boat last and had simply operated the lever without being concious of which way I was moving it. DOH!

Anyway, opened the pump, pulled the wrecked impellor out, blew out the hoses to get the broken bits out, repaired the damaged hose, fitted new impellor and gasket, made sure that the seacok was open this time and set off again.

Moral of this £25 story is, don't just move it, check it moved on the right direction.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

When we start the engine we always go and check that water is coming out of the exhaust pipe. It is a sound habit but of couse it only applies to watercooled exhaust systems and only if you can see the exhaust but thats the majority!

You should check your exhast hoses and any plastic bits.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

and if not get clear plastic tops for raw water filters!! i had awfull brass things - i replaced then for nice vetus ones, and never looked back!!
 
Re: How to Ruin Impellor AND Water Pump . . .

. . . by going SHOPPING???

Yep. A Waitrose plastic bag got sucked into the inlet seacock (even my bog-ups are good quality!). Didn't notice anything wrong until the engine spluttered to a halt (well, you do go round looking at the temp. gauge, don't you???

Not only a charred impellor but a cracked freshwater cooling pump (that's the one you never worry about, unlike the seawater thing.) Megabucks to replace, equal amount to fit TWO Halyard sensors from the firm who specialise in cooling alarms.

Don't even look over the stern anymore: if water doesn't flow that alarm is deafening! Reaction time < two seconds.

Highly recommended - do PM me if you want more details.
 
Re: How to Ruin Impellor AND Water Pump . . .

I've been lucky - only once last year did we have a near miss - got father to turn everything on whilst I cast off - fired up engine, cast off - potter down the channel ... BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEP ... I've never dived down below so fast before!! ... Silly chump didn't realise we turn off all seacocks ... even worse - it was right in front of his eyes when he turned the electrics on ...

Ah well - luckily no damage, just turn on the raw water and away we go ...

I now always double check with who ever turns on the electrics that they have turned on the water - I'll miss it again one day though...
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

That is exactly the sort of mistake I might make. Hand on engine intake seacock, I usually stop for a second and think "lever in line with hose?".

Must admit I am often distracted by notice crew and skip the check for water flow bit. When on the boat for a few days I leave to engine intake open until I go home.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

This thread makes lots of sense if you ever look at a boat prepared to the "safety at sea" seminar recommendations. Labels on everything in very large type, and arrows to indicate where levers and switches should be. I was astounded to see the detail to which an owner had set up his boat in preparation for a Sydney Hobart, but it all makes sense when people start talking about these sort of issues.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

What has worked for me [so far!] is to hang the engine key on the seacock handle when I close it.

Also a clear plastic topped filter [Vetus, as mentioned above], enables you to see at a glance that the water is flowing.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

I know its not exactly the most PC solution, but we have a gate valve in the raw water inle. No possibility of turning it the wrong way there. And before anyone goes on about the unreliability of gate valves, I know, and will get around to replacing it when it starts to play up, which will be any decade now. It's probably been on the boat from new.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

Couple of observations (from experience!)

Checking exhaust water has to take place some time after the engine start on installations with long pipes and water mufflers. It takes about 2 minutes to empty my system!

Besides removing bits of impellor from the pipes, inspect the heat exchanger piping if you've got a salt/fresh water heat exchanger. Smaller bits will stick in there very effectively blocking a percentage of your flow . . .

When my seacock is off, a label moves from the seacock to hang over the engine keyboard - 'sea cocks closed'

And yes, the Halyard exhaust sensor is excellent, kicks in after about 20 to 40 seconds of dry running. Which is sometimes too late to save the impeller, but fine to save everything else.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

glad it's not worse - sorry you had the extra work.

adding a ping pong ball or similar under the plate in the raw water makes it obvious if water is flowing - really really in your face obvious.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

Fit an RS Components flow switch inline with the pump, this will warn if water flow stops.

There was a tip in PBO some months ago showing haw this could be done.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

I don't turn my sea cocks off...occasionally i try them to see if they are free....i live on board so am always around if something goes wrong ...

Am i missing something
 
Untidy I know ..... but permament marker pen !

Written across engine starter box "door" is "OPEN SEACOCK BEFORE STARTING!"

As to alarms ... you can buy digital probe / displays in car acc's shops for less than a tenner ... fix to suitable points on engine and exhaust ... you can even get them with settable alarms !!

But yes the look over the a**end at exhaust outlet is a MUST do ....
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

On the last boat, I fitted a temperature sensitive switch to the exhaust elbow and linked it to an electronic sounder. I have not got round to doing it on Wight Dawn yet (only had it 9 years and you can hear the exhaust from the wheel position.) If anyone is interested in doing the same, the switch used was a 75 degree one available from RS Components, as is the sounder.

Shortly after leaving Millport one morning this year, the exhaust noise changed in tone and volume. As the wind was by then strong enough to sail, the engine went off and we got to Lochranza, where we picked up a mooring to check things out. The cause of the problem was jellyfish, which had almost completely choked the intake filter.
 
Re: Untidy I know ..... but permament marker pen !

A friend of mine uses an alarm built for aquariums! Temp range must be suitable, not sure if the fish would be happy at the top end of the scale......
Cost a fiver, I think.

I always look over the back as soon as the engine fires. Doesn't help if inlet gets blocked while underway, though. Must get down the tropical fish shop.
 
Re: How to Ruin a Pump Impellor thru\' Automatic Actions

I don't live on board but sometimes I forget. This year, the first time I used the engine I found water filling the bilges. On investigation there was a small jet of water from a hole that had corroded through the copper pipe (swan neck) between the valve and the flexible hose.
 
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