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Author Topic: Water pump problem  (Read 3796 times)

Bluechrisp

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Water pump problem
« on: May 05, 2011, 06:36:53 PM »

Evening all,

Just tried out my new 12v graupner pump, doesn't seem to work unless the whole circuit is full of water. I am using it to pump out the water from the boat during heavy seas on the pond! The circuit wouldn't be full of water anyway.
It should work anyway shouldn't it?
The pump is about 2 inches above the bottom of the boat and the out let 3 inches.

Any help or tips?

Many thanks

CP
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john s 2

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Re: Water pump problem
« Reply #1 on: May 05, 2011, 06:54:05 PM »

Can i suggest fitting a one way Valve before the Pump this will ensure the Pump is kept primed. Use a washer Bottle valve. Hope this helps. John.
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Umi_Ryuzuki

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Re: Water pump problem
« Reply #2 on: May 05, 2011, 07:28:17 PM »

If I recall correctly, at least three of the four styles of Graupne water pumps are
impeller driven, and not self priming. They work best when they below the waterline
of the boat, and drawing water from the pond. Unless you have the gear pump, then
drawing water 2" up from the bottom of boat will be an issue. Every time the pump gets
a gulp of air, it will stall.

 {:-{
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Bluechrisp

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Re: Water pump problem
« Reply #3 on: May 05, 2011, 07:43:12 PM »

If I recall correctly, at least three of the four styles of Graupne water pumps are
impeller driven, and not self priming. They work best when they below the waterline
of the boat, and drawing water from the pond. Unless you have the gear pump, then
drawing water 2" up from the bottom of boat will be an issue. Every time the pump gets
a gulp of air, it will stall.

 {:-{
if that's the problem, what do I need to do to pump out the water from the bottom( which pump), Could I have have a feed from the pond connected to a Y connector So draw from pond and boat?

CP
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boatmadman

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Re: Water pump problem
« Reply #4 on: May 05, 2011, 08:00:26 PM »

Umi is correct if it is an impellor pump.
You have limited options:
1: resite the pump so that the case is always below the water level.
2: change the pump for a positive displacement type - a gear pump. I think graupner do one.

This type will always work ok but are noisier. You should still keep this type of pump close to the keel. Doing this means the pump will self prime quicker.

Ian
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Roadrunner

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Re: Water pump problem
« Reply #5 on: May 05, 2011, 08:50:50 PM »

I'm going to add my sarcastic comment of the day, so don't get wound up... surely the boats not meant to take in water in the first place? Perhaps fixing where the water comes in would be better time served, ( higher combing, sealing holes in the deck line with resin,  etc, etc)  or better don't run the model in rough water if you cannot stop the intake.

There are other methods of removing water from a boat if you intend to carry on without the use of a pump... put a water outlet behind the prop, when it spins it will draw the water out at the same time it moves ,although this really works best for boats that never remain stationary for periods of time, such as the fast electrics etc.

The only water intake a boat should get will be through the prop shafts, and this usually occurs when the shafts become worn and old, as there is more wear making a larger gap up the shaft, or when the boat has a water ballast system.  :-))  ok2
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Bluechrisp

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Re: Water pump problem
« Reply #6 on: May 05, 2011, 10:33:24 PM »

I'm going to add my sarcastic comment of the day, so don't get wound up... surely the boats not meant to take in water in the first place? Perhaps fixing where the water comes in would be better time served, ( higher combing, sealing holes in the deck line with resin,  etc, etc)  or better don't run the model in rough water if you cannot stop the intake.

 :-) I have the Tsoka2,  the water comes in from the under the back hatch, I'm a all weather model boater, the water comes in from the sides and over the deck, nothing like a good deck wash. Our collection of motley boaters tend to spend hours out on the water,  :o so hence the pump  :} we also carry out ice patrol as well, which intales ice pushing at times, all good fun.  :-))

CP
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Roadrunner

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Re: Water pump problem
« Reply #7 on: May 05, 2011, 10:39:42 PM »

Simple's fix the back hatch if that's where the water comes in .. seal it with some Vaseline or grease or make a secondary cover that sits inside the section, or even plaster it in sticky tape!

(i have to do that to my yacht hatch as its a poor fit and making a new one is a lot of work given the openings shape and angles) 

Trick is stop water getting in , as this will damage motors , electronics in the long run, no water no pump needed = more run time since the pumps not chewing up the power keeping the water from sinking the vessel!
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geoff p

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Re: Water pump problem
« Reply #8 on: May 09, 2011, 07:39:03 AM »

Take all of RR's advice and also fit a continuously-running bilge pump but of the self-priming sort.

I have modified an old aquarium air-pump (240V 50Hz) to run from a low-current geared motor,
http://www.purpletiger.com/geoff/model_boats/mistral/cooling_pump.MkII.html
and this pumps about one litre in eight minutes running on 6 Volts.  Not terribly fast but constantly available.

Just another idea.

Geoff
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Bluechrisp

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Re: Water pump problem
« Reply #9 on: May 09, 2011, 10:55:37 PM »

Road Runner,

I will track down some light foam tape, that should do the trick I hope... like you say, we pay out our hard earned money not to see it get drenched and blow up  %)

Geoff,

Good idea, I have a self priming geared pump and will add this, I will be adding a fire monitor to make things more interesting, feed from the boat and the pond.  :-))

Many thanks again


CP
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Roadrunner

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Re: Water pump problem
« Reply #10 on: May 09, 2011, 11:09:56 PM »

Good lad, nothing wrong with using a pump if the model does take on water but the first rule should be to stop or significantly reduce intake before using such devices.
Should water short the battery even with a pump the loss of power will i have no doubt in rough weather mean the loss of the boat unless quick rescue can be obtained.
If you need extra security in being sure the boat won't sink you may like to fill all the gaps in the hull with polystyrene or expanding foam, this will at least make the boat positively buoyant and stop water from taking up the empty space in the boat.  :-)) 
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portside II

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Re: Water pump problem
« Reply #11 on: May 10, 2011, 05:04:41 PM »

I have a fuel pump in my tug , the ones used for filling nitro tanks on model aeroplanes .
On the intake i have a short length of tube with a clunk fitted (piece of brass to keep the pipe on the bottom) the pump is self priming and works fine.
As for stopping the water getting in in the first place , tried that , a bit hard when your stern goes under the water when towing  :embarrassed: ,
but it works for me and has the added efect as a bilge/cooling pump out the side.
daz
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Bluechrisp

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Re: Water pump problem sorted
« Reply #12 on: May 18, 2011, 05:42:13 PM »

Hello all,

Well the pump has been fitted and by god it shoots out, it even turns the boat in the water,  :o Now for this hatch, build another at least this one will have a decent combing once dry I think I'll put in that a water monitor and put it into good use.

CP
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portside II

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Re: Water pump problem
« Reply #13 on: May 18, 2011, 10:56:38 PM »

If the water is more of a jet try fitting a Y coupling in the outlet hose one pipe to either side , this will reduce the flow and maybe an obstuction on the end's
i have the outlet's covered by the tyre fenders on my tug.
daz
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Bluechrisp

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Re: Water pump problem no more?
« Reply #14 on: June 01, 2011, 10:12:46 PM »

Hello all,

I have fitted out my new waterproof hatch for the Tsekoa2, this was done as water was going under the old one, so I made a new one, this one has the top of the engine room hatch coming off, so I can get to the electrics etc. The hatch assembly has been stuck down with clear silicone sealant,  and all other weak areas covered too. That should please Road Runner, :-)

The pump is now being used for the water monitors at the front.





Cheers all


CP
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Shipmate60

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Re: Water pump problem
« Reply #15 on: June 01, 2011, 10:28:23 PM »

RR.
NEVER use expanding foam in a model boat.
It dies what it says - expands when heated. It has to as the air bubbles expand.
I have seen several models wrecked when the foam expanded and forced the deck up.

Bob
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Roadrunner

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Re: Water pump problem
« Reply #16 on: June 02, 2011, 12:21:46 AM »

lol yay! well chuffed, that should keep the water out!

Shipmate... I've never had issues with expanding foam, nor have many others that have used it in there boats, especially the fast electric boys, since most of there models are filled with the stuff, and no ill effects, now its either pure luck that i and many others i know have not had issues or you used the foam to close to the motors. (since there the only real things that's can heat up enough to set the foam off again!)

Although expanding foam is not cheap as it used to be i have swapped to polystyrene since i have like a ton of it in the garage!, either in block form or in beads, which are good for filling compartments.

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Shipmate60

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Re: Water pump problem
« Reply #17 on: June 02, 2011, 07:02:03 AM »

Polystyrene is fine.
This subject has been covered before on here.
The models I saw damages were rather good warships. The bow was filler with the stuff.
While on display in Glasgow in the sun the whole foredeck lifted.
It will also absorb some water which will take an age (if ever) to dry out.

Bob
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Roadrunner

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Re: Water pump problem
« Reply #18 on: June 02, 2011, 08:48:43 AM »

I have a feeling that this is one of those discussions that both sides are right and the argument will always be there, do i or don't i, it probably comes down to how its used either squirted in until the gaps filled rock solid or used sparingly little by little to fill the gap but not compact it. As ive said others & i have not had problems with it.
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