Unexpected impeller malfunction

How things work, what's hot and what's not
User avatar
Nick
Admiral of the Blue
Posts: 5738
Joined: Sun May 12, 2002 4:11 pm
Boat Type: Albin Vega 27
Location: Oban. Scotland
Contact:

Unexpected impeller malfunction

Postby Nick » Fri Jul 03, 2015 12:06 am

.
Just popped out of the top of the Sound of Luing today as the tide turned North when the engine overheat alarm went off. Stopped engine, wind died completely and we started inexorably drifting directly towards Bono Rock.

Found the engine seacock, whipped (well not 'whipped', Volvo engine, six tiny wee bolts) the cover off and had a look. Impeller looks perfect, all blades intact, correctly oriented, nicely flexible. Check strainer, a few wee bits of weed, nothing serious. Initially there seemed to be no/low water flow through the strainer, which made me think the inlet could be obstructed, but by the time I get the dinghy pump out of the cockpit locker to give it a blow-through it is flowing normally.

Much head scratching, call up nearby yachts re. a possible tow into Easdale to moor up for more detailed investigation, comms problems on a working channel I get the hand-held up on deck and a friendly voice says they are on the way up the SoL and will be with us in twenty mins or so. Thanks Sea Fever.

Meanwhile, the clients are fighting in the cockpit and generally getting in the way. We are now less than a cable from the Bogha Nuadh W. cardinal. I decide I will replace the impeller anyway, remove cover and pull the old one out. The problem is revealed. The spindle is missing, just a tiny 1mm stump at one side. I fit the new impeller, fire up the donk and we make good our escape.

Has anyone else had an impeller fail in this way?
- Nick 8)

Image

User avatar
Telo
Admiral of the Red
Posts: 2493
Joined: Wed Jan 05, 2005 9:27 pm
Boat Type: Vancouver 34 Pilot
Location: Bampotterie-sur-mer
Contact:

Re: Unexpected impeller malfunction

Postby Telo » Fri Jul 03, 2015 12:53 am

Nope.

Gardenshed
Old Salt
Posts: 312
Joined: Sun Apr 26, 2009 3:59 pm
Boat Type: Grand Soleil 39 & Hobie Tiger
Location: 13:44:00N 100:32:00E

Re: Unexpected impeller malfunction

Postby Gardenshed » Fri Jul 03, 2015 2:18 am

"Meanwhile, the clients are fighting in the cockpit"

Tell us more!
Which page of the RYA-way explains how to deal with cockpit-fisticuffs?

User avatar
claymore
Admiral of the Green
Posts: 4379
Joined: Sun Oct 19, 2003 2:55 pm
Boat Type: Claymore
Location: Ardfern or Lancashire

Re: Unexpected impeller malfunction

Postby claymore » Fri Jul 03, 2015 8:39 am

Isn't the Bono rock the one that gets moved from time to time?
Did you consider mooring to the Cardinal mark?
Was there a clear winner in the Cockpit Scuffle?
Were you considered a hero by the Non Combatants?

Your post raises more questions than answers...
Regards
Claymore
:goatd

User avatar
Nick
Admiral of the Blue
Posts: 5738
Joined: Sun May 12, 2002 4:11 pm
Boat Type: Albin Vega 27
Location: Oban. Scotland
Contact:

Re: Unexpected impeller malfunction

Postby Nick » Fri Jul 03, 2015 8:59 am

Yes
Yes
No
Yes
- Nick 8)

Image

User avatar
Nick
Admiral of the Blue
Posts: 5738
Joined: Sun May 12, 2002 4:11 pm
Boat Type: Albin Vega 27
Location: Oban. Scotland
Contact:

Re: Unexpected impeller malfunction

Postby Nick » Fri Jul 03, 2015 9:01 am

.
I see that posting this in our technical forum was a mistake :hat
- Nick 8)

Image

User avatar
mm5aho
Old Salt
Posts: 930
Joined: Sat Jul 31, 2010 9:40 pm
Boat Type: Rival 32
Location: West Lothian
Contact:

Re: Unexpected impeller malfunction

Postby mm5aho » Fri Jul 03, 2015 9:30 am

I have on occasion noted that the pin that really drives the impeller is loose. (I've changed this impeller almost annually). Some come with a tight pin, some with a loose one.
But I can't see how it could escape unless this happened on installation? It would have to pierce the brass sleeve, then the rubber and then disappear down the coolant route to get lodged somewhere in an elbow or the heat exchanger?

I'm assuming this is the same as ours on a Volvo MD2030. The impellor has a brass insert inside the rubber, and this is what fits over the shaft that drives it. Inside that brass sleeve there's a pin at 90 degrees to the direction of the shaft, and this pin fits a small slot in the shaft end.

But the story is interesting too. "client" doesn't explain whose boat. Theirs or yours? Did you have to solve such an issue on their boat?
Geoff.
"Contender" Rival 32: Roseneath in winter, Mooring off Gourock in summer.

User avatar
Nick
Admiral of the Blue
Posts: 5738
Joined: Sun May 12, 2002 4:11 pm
Boat Type: Albin Vega 27
Location: Oban. Scotland
Contact:

Re: Unexpected impeller malfunction

Postby Nick » Fri Jul 03, 2015 9:41 am

.
Not my boat.

No internal bronze bush in the impellor, just the rubber part with a tiny stub on threaded spindle embedded in one side of the rubber hub. Wish I had taken a pic now.

The main problem was, on initial inspection the impeller looked intact and functional, which led me to spend some time looking elsewhere.
- Nick 8)

Image

User avatar
mm5aho
Old Salt
Posts: 930
Joined: Sat Jul 31, 2010 9:40 pm
Boat Type: Rival 32
Location: West Lothian
Contact:

Re: Unexpected impeller malfunction

Postby mm5aho » Fri Jul 03, 2015 10:52 am

I once encountered a new impellor where the bronze bush wasn't exactly right and would not fit over the shaft. A round file sorted it!
Geoff.
"Contender" Rival 32: Roseneath in winter, Mooring off Gourock in summer.

User avatar
ash
Yellow Admiral
Posts: 1717
Joined: Tue Mar 01, 2005 12:14 pm
Boat Type: Moody 346
Location: Tarbert, East Loch Tarbert, Loch Fyne, Scotland

Re: Unexpected impeller malfunction

Postby ash » Fri Jul 03, 2015 12:19 pm

Which engine / pump no?

I too would expect to see the pin to cross the full width of the hole (the hole for the shaft )

Ash
"This is a sailing Forum"
Albin Vega "Mistral" is now sold

User avatar
claymore
Admiral of the Green
Posts: 4379
Joined: Sun Oct 19, 2003 2:55 pm
Boat Type: Claymore
Location: Ardfern or Lancashire

Re: Unexpected impeller malfunction

Postby claymore » Fri Jul 03, 2015 3:27 pm

Frankly - you lads are getting a bit anal about the fekking bronze pin - lets get back to the fracas in the cockpit.......
Regards
Claymore
:goatd

User avatar
ash
Yellow Admiral
Posts: 1717
Joined: Tue Mar 01, 2005 12:14 pm
Boat Type: Moody 346
Location: Tarbert, East Loch Tarbert, Loch Fyne, Scotland

Re: Unexpected impeller malfunction

Postby ash » Fri Jul 03, 2015 4:28 pm

claymore wrote:Frankly - - lets get back to the fracas in the cockpit.......

Maybe someone realised that the number of people on board was one more than the capacity of the liferaft!! :roll:

Ash
"This is a sailing Forum"
Albin Vega "Mistral" is now sold

User avatar
claymore
Admiral of the Green
Posts: 4379
Joined: Sun Oct 19, 2003 2:55 pm
Boat Type: Claymore
Location: Ardfern or Lancashire

Re: Unexpected impeller malfunction

Postby claymore » Fri Jul 03, 2015 4:59 pm

Can't be that Ash, Nick would have walked ashore
Regards
Claymore
:goatd

User avatar
aquaplane
Admiral of the White Rose
Posts: 1522
Joined: Thu May 17, 2007 12:55 pm
Boat Type: Jeanneau Espace
Location: Body: West Yorks; Boat: Tayvallich
Contact:

Re: Unexpected impeller malfunction

Postby aquaplane » Fri Jul 03, 2015 6:37 pm

claymore wrote:Can't be that Ash, Nick would have walked ashore


You have a thing about folk walking on water don't you?
Seminole.
Cheers Bob.

User avatar
sahona
Admiral of the White
Posts: 1982
Joined: Thu Jan 03, 2008 8:17 pm
Boat Type: Marcon Claymore
Location: Clyde

Re: Unexpected impeller malfunction

Postby sahona » Fri Jul 03, 2015 7:58 pm

I think I've seen this before. Cockpit chaos is not unusual in my experience, so we bought a boat without one. Wheelhouse whinging is a less hazardous but still irksome phenomenon.
The impellor - was it, could it have been, a little grubscrew sort of thing that went missing? I've got memories of an SS headless screw across the bore in an impellor with no other metal visible in the hub (but it might have been encapsulated in the rubber). This lay in a slot in the shaft and transmitted power to the impellor. I guess yours possibly wasn't stainless, in my case the screw was still there but the impellor hub was all gronched up. Johnson pump?
http://trooncruisingclub.org/ 20' - 30' Berths available, Clyde.
Cruising, racing, maintenance facilities. Go take a look, you know you want to.


Return to “Gear and Gadgets”

Who is online

Users browsing this forum: No registered users and 4 guests