SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Nov 13, 2012, 08:38 AM
Registered User
Rmay's Avatar
Louisiana
Joined Sep 2006
1,330 Posts
Some interesting work with water ballasting is going on over here.http://www.modelboatmayhem.co.uk/for...?topic=36872.0

Always a treat when we’re educated here on the forum by IMHO one of the masters!

Thanks Pat.
Rmay is offline Find More Posts by Rmay
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 13, 2012, 08:49 AM
Registered User
DDG 51's Avatar
EUrope
Joined Apr 2008
842 Posts
Yes , interesting. But on the model, water level in the balast tank can not be higher as waterline. CG will be to high. Plus, there will be required water pump. In my ships with water tanks, I have water level in the tanks 1/2 in below water line of the hull. Never had problem . Of course, on the tug boats, not on the narrow and long hulls. Tank system will be worthless on hulls as Ticonderoga, USS Long Beach ....There is lead required and a LOT
DDG 51 is offline Find More Posts by DDG 51
Reply With Quote
Old Nov 13, 2012, 08:50 AM
Veni, Vidi, Feci
patmat2350's Avatar
Motor City
Joined Dec 2004
12,769 Posts
Water ballast can be ok… but keep in mind:

1. Water is 1/3 the density of lead shot… so 3x more volume is required inside the hull. This may be an issue when you are looking for space for other components.
2. Free-flooding water ballast is a problem in large models… you still have to lift the ballasted model out of the water, for the water to drain! (ouch, my back…)
3. Jeff Churill used to have an article up about his pumped water ballast system, but I think the site has gone off line. It worked well in his huge HO-scale 1000 foot laker.
patmat2350 is offline Find More Posts by patmat2350
Reply With Quote
Old Nov 13, 2012, 02:57 PM
r/c ships and workboats
bellingham, wa
Joined May 2006
4,675 Posts
one other issue about water ballast--contamination transfer. Moving water from one source to anoth may allow you to introduce hazzard into another body of water accidentally ( unless in treated water source. One other issue with water ballast, water retention can also create amold issue with in the model as it is out of site and hidden ( as well as sealed). just my 2 cents worth.
Like your ballast ideas there Pat. Some neat and creative ideas.
keith S is offline Find More Posts by keith S
Reply With Quote
Old Nov 13, 2012, 07:21 PM
Registered User
Kamloops BC Can.
Joined Jan 2008
641 Posts
My 2 cents worth. Am using water ballast to tip my logging barge. Using a w/w pump to take on water. Fills the tank pretty quickly. Just not a big enough tank for log dumping. will have to add to it. Also tried draining tank by running pump backwards. It does run, but a lot lower pressure/volume than when filling and takes about 4 times longer to drain. Back to the drawing board. Looking at servo operated directional valves so that the pump is aways running in the forward position filling and emptying.
Olscuzbut is offline Find More Posts by Olscuzbut
Reply With Quote
Old Nov 14, 2012, 01:48 AM
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Australia, QLD, Regents Park
Joined Mar 2007
3,735 Posts
Quote:
Originally Posted by patmat2350 View Post
Water ballast can be ok… but keep in mind:

1. Water is 1/3 the density of lead shot… so 3x more volume is required inside the hull. This may be an issue when you are looking for space for other components.
By my calculations its about 7-8 times denser 1 cc (Cubic Centimeter) of water is 1 gram, 1 cc of lead is 11.3 gram 70 % density makes it about 7-8 g per cc. that would meen 7 to 8 times more water needed.

Nick
nick_75au is offline Find More Posts by nick_75au
Reply With Quote
Old Nov 14, 2012, 05:52 AM
Speed Demon
Örsundsbro, Sweden
Joined Oct 2006
91 Posts
I found a pump that does the job. A bit on the expensive side maybe, but works in both directions.
Xatan is offline Find More Posts by Xatan
Last edited by Xatan; Nov 14, 2012 at 06:18 AM. Reason: Ah, it's a 6-12V pump, I run it on 11.1V.
Reply With Quote
Old Nov 14, 2012, 11:47 AM
Registered User
DDG 51's Avatar
EUrope
Joined Apr 2008
842 Posts
Watertanks in my Braveheart tug and in Tito neri works absolutly GREAT.There is not reqiured moving 20 lb of lead. Water is in every single lake. Some pictures included
DDG 51 is offline Find More Posts by DDG 51
Reply With Quote
Old Nov 14, 2012, 06:38 PM
Nickel Belter
ZZ56's Avatar
Northern Ontario
Joined Jun 2009
865 Posts
I used Pat's steel shot tank idea on my latest build and it works great. I can't find lead shot so I used powdered steel from an old set of ankle and wrist weights.

I like it so much I'm going to go back and replace the bagged steel powder in my other tug with permanently placed shot tanks.

ZZ56 is offline Find More Posts by ZZ56
Reply With Quote
Old Nov 14, 2012, 06:53 PM
Chris Craft Corvette
42Corvette's Avatar
United States, SC, Charleston
Joined Mar 2006
211 Posts
Hi Pat,
Whose kit is the DUKW? Thanks, Dick
42Corvette is offline Find More Posts by 42Corvette
Reply With Quote
Old Nov 14, 2012, 07:27 PM
Veni, Vidi, Feci
patmat2350's Avatar
Motor City
Joined Dec 2004
12,769 Posts
Kit? Puh-leese!

http://www.rcgroups.com/forums/showt...5#post13698908

patmat2350 is offline Find More Posts by patmat2350
Reply With Quote
Old Nov 15, 2012, 12:36 PM
Chris Craft Corvette
42Corvette's Avatar
United States, SC, Charleston
Joined Mar 2006
211 Posts
Sorry to have insulted you. There's just no way for me to have known--my crystal ball being in the repair shop and all.
42Corvette is offline Find More Posts by 42Corvette
Reply With Quote
Old Nov 15, 2012, 03:01 PM
Veni, Vidi, Feci
patmat2350's Avatar
Motor City
Joined Dec 2004
12,769 Posts
Now, you know that's no prob!
BTW, I only know of one DUKW kit, from Deans Marine... CG Bob built one...
patmat2350 is offline Find More Posts by patmat2350
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Link Video link to dual syringe ballast tank CarreraGTSCS Submarines 10 Jan 27, 2007 11:39 PM
Discussion Revell VIIc/41 piston ballast tanks gpw-Pat Submarines 3 Apr 10, 2006 08:22 PM
Piston type ballast tank question CarreraGTSCS Submarines 21 Oct 29, 2005 03:06 AM
Ballast Tank Pumps Tregurtha1013 Dock Talk 5 Dec 10, 2004 08:29 AM
ballast tank and blow system Netminder321 Submarines 3 Jun 07, 2004 11:01 AM