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.

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

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.

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.

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.

Originally Posted by patmat2350

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

I found a pump that does the job. A bit on the expensive side maybe, but works in both directions.

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

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.

Hi Pat,
Whose kit is the DUKW? Thanks, Dick

Kit? Puh-leese!

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

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.

Now, you know that's no prob!
BTW, I only know of one DUKW kit, from Deans Marine... CG Bob built one...