Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: EXHAUST WATER  (Read 2936 times)

Roger in France

  • Guest
EXHAUST WATER
« on: August 26, 2006, 06:50:32 PM »

Am planning (very early days) a large model tug. As most ships eject waste water all the time when engine running I wondered if anyone has a simple method to make the expelled jet of water intermittent? I think a continuous, uniform stream would look wrong.

Before I scratch my head too much I thought I would see who has already invented the wheel!

Roger in France.
Logged

Stavros

  • Guest
Re: EXHAUST WATER
« Reply #1 on: August 26, 2006, 07:23:13 PM »

Bonjour easy m8 get 1 water pump from a car connct +to +on wires to motor -to -on same and hey presto as motor speed inceases so does the volume of water thta is all I have done on my Sea Queen and it works
Logged

wombat

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 642
  • The view from the shallow end of the gene pool
Re: EXHAUST WATER
« Reply #2 on: August 26, 2006, 07:57:55 PM »

How about a small motor with a wheel on it - use the wheel to switch a microswitch on and off as it rotates (by cutting notches in it). Use this to switch the pump on and off - this should with a bit of luck give a pulsing jet. Run the motor off the main drive and the rate of pulsing will follow the speed of the motors.

Tim the Wombat
Logged
The prat in the hat - www.floatingwombat.me.uk - Have look & say Hi

Martin [Admin]

  • Administrator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 19,055
  • Location: Peterborough, UK
    • Model Boat Mayhem
Re: EXHAUST WATER
« Reply #3 on: August 26, 2006, 08:40:29 PM »



What about using some sort of air pump as a pump like in a fish tank filter.
The bubbles along or up a tube drawing water along with it.



Logged
"This is my firm opinion, but what do I know?!"    -   Mayhem FaceBook Group!

boatmadman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,721
  • Location: South Cumbria
Re: EXHAUST WATER
« Reply #4 on: August 26, 2006, 11:05:36 PM »

What about trying a slow speed reciprocating pump?

Maybe one driven by a crank geared down from a motor?

Ian
Logged
if at first you dont succeed.....have a beer.....

Shipmate60

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,264
  • You bark - I will bite!!!
  • Location: Fareham
Re: EXHAUST WATER
« Reply #5 on: August 26, 2006, 11:38:10 PM »

The water from the hull is from the Main Engines and Generator overboard discharges.
The water is used to cool the Engines in large Heat Exchangers.
Most modern vessels have electris driven pumps eo the discharges dont vary much.
The ships with variable outlets are from engine-driven pumps.
If you want a variable output connect a speed controller on a "y" lead from the throttle.
Or
Wire in the pump via the main motor wiring which will be controlled by the main speed controller.
Main problem will be to find a pump thet will react as you want.
Possibly windscreen washer pump?

Bob
Logged
Officially a GOG.

2772e

  • Simon
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 452
  • The Sea Shall Not Have Them
  • Location: Colchester, Essex
Re: EXHAUST WATER
« Reply #6 on: August 27, 2006, 09:23:43 AM »

Roger,

I was talking to JJC a couple of weeks ago and he is developing a pump for the lifeboat boys that is linked to start up, engine speed, and running etc. You might want to give him a go? Works with the smoke machine as well. all proportional?

Regards

Simon
Logged
Rubbin is Racin!

Aston

  • Guest
Re: EXHAUST WATER
« Reply #7 on: August 27, 2006, 11:33:20 AM »

as you are planninga big tug, plenty of room, and presumably running on 12 volts, if you want an intermottent pulse of water coming out of the outlet, why not wire the pump feed thrugh a car indicator relay.  This will pulse the pump at the same speed your indicator lights flash at.  You don't get any variation with speed, but that's a different problem.

Alternative is to have a look at the Maplins web site or catalogue and look at some of the flasher circuits they have in the projects book.  There are circuits where you can alter how often it flashes, and how long the power is on / off  when it does.

Aston
Logged

White Ensign

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 779
  • Limits must be limited!
  • Location: Stuttgart, Germany
Re: EXHAUST WATER
« Reply #8 on: August 29, 2006, 11:20:38 AM »

Hi RIF,
a friend of mine had used a so-called membran-pump, which gives a good pulsation, just like the origin. Also there was a report in a German mag, where a lad had taken a piece of silicone-tube and a slow running motor with a disc where 5 rollers had been mounted. The rollers went over the tube and pressed a bit of water outside. The tube filled up with water just before the next roller of the disc went over the tube to push out the next bit of water. Looked good to me as well.

Hope this was out of any help for you.

Jörg
Logged
When God created planet earth, he made it with 75% of water. Bet he had the modelboaters on his mind!

Shipmate60

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,264
  • You bark - I will bite!!!
  • Location: Fareham
Re: EXHAUST WATER
« Reply #9 on: August 29, 2006, 09:15:55 PM »

The outlet SHOULDNT pulse, it should be a constant stream, but on older engines getting faster as the main engine speeds up.
The generators are constant speed.

Bob
Logged
Officially a GOG.

Colin Bishop

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 10,280
  • Location: SW Surrey, UK
Re: EXHAUST WATER
« Reply #10 on: August 29, 2006, 09:58:09 PM »

Quote
The outlet SHOULDNT pulse, it should be a constant stream, but on older engines getting faster as the main engine speeds up.
The generators are constant speed.

Quite right for larger craft but for smaller ones, i.e. launch types, with diesel engines you do get a pulse effect as the exhaust gases force out the cooling water from the exhaust system. With very small boats such as yachts with outboards you just get a constant stream from the "telltale"to indicate that the cooling system is working. Not that this is likely to be apparent at model scales. With rowing boats it's just perspiration while with submarines you should be getting worried....
Logged

White Ensign

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 779
  • Limits must be limited!
  • Location: Stuttgart, Germany
Re: EXHAUST WATER
« Reply #11 on: August 30, 2006, 08:07:05 AM »

Colin, if it is persiperation running down your back, passing your rear outlet I am sure it will pulse while you are rowing...  ;D

Jörg
Logged
When God created planet earth, he made it with 75% of water. Bet he had the modelboaters on his mind!

cbr900

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,871
  • Mayhem is the Only Forum!
  • Location: Taree New South Wales Australia
    • Roys Hompage
Re: EXHAUST WATER
« Reply #12 on: September 26, 2006, 09:58:28 AM »

And at times it will also blow bubbles.... ;D ;D

Roy
Logged
I try not to be naughty but nautical

Colin Bishop

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 10,280
  • Location: SW Surrey, UK
Re: EXHAUST WATER
« Reply #13 on: September 26, 2006, 10:44:29 AM »

What extraordinary imaginations you guys have! Is nowhere safe? Can't turn your back for a moment.... :o :o
Logged

cbr900

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,871
  • Mayhem is the Only Forum!
  • Location: Taree New South Wales Australia
    • Roys Hompage
Re: EXHAUST WATER
« Reply #14 on: September 26, 2006, 11:10:52 AM »

What extraordinary imaginations you guys have! Is nowhere safe? Can't turn your back for a moment....

Colin life is to short not to have fun as well enjoy mate,


ROGER,

If it it a large Tug model is it a large tug you are modelling, if so the exhaust would be constant as it would be powered by a generating system...


Roy
Logged
I try not to be naughty but nautical

Tug

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 163
  • Location: France [86]
Re: EXHAUST WATER
« Reply #15 on: September 26, 2006, 02:20:06 PM »

My thoughts led me to think of an automatic loo flush, (me disturbed? perhaps)

 small 'sealed' tub with a syphon arangement, to cycle in pulses. trickle in pulsed flushes out.  could even fill it from a cooling coil inlet so no pumps, no motors, no batteries to go flat?

[but what does he know?]
Logged
Junk is something you've kept for years and throw away three
 weeks before you need it.
Pages: [1]   Go Up