Test Tank construction / ballast pour

[cshelden]

Hello all,
Things are moving slow here in Oklahoma City on the new EC12 fleet but they are moving none the less. I am begining the process of gathering materials for the test tank. I've seen it ref with 1/4" and 1/2" plexi glass. Will either work ok? I've found materials for a 1/4 tank to be about 45.00 here in town and they will cut to my diminsions, didn't price 1/2" yet.

Second question, we will be pouring our own ballast here. I've not been able to dig up the info for the angle in which the hull should be in the water when the ballast is poured, is this a dark secret only known to the "Knights of the 12", or am I just not seeing the forest for the trees? Any help in this area would be much appreciated.

Thanks again,
Charlie
OKC, OK
SSMYC #109 AMYA

[Carl]

The test tank at the 2004 Nationals was all metal and I don't recall any side being clear.
They also just used a string across the tank at the 42 inch mark.
Nothing fancy and it works. I have seen tanks made out of plywood and painted - just don't leave the water in it.
You do need a method to level the tank so that the water flows over each side fairly equal.

Carl

[kermwood]

Hi Charlie
l built my own tank here in the UK.In my opinon you need to go for the heavy gauge if you use plastic sheet.
l used 12mm thick Plastic for several reasons.
(1)having a clear front is good for seeing whats going on under the waterline.
(2) l was able to drill and tap the ends plates and screw them in place with silicon to seal joints.
One thing to bear in mind is the weight and pressure on sides and base.
l layed base on flat surface and loaded it up with weight before fitting sides on top of base with silicon,So that when the weight of water was in the tank the base was already the shape it would be with the water in.
Rick has good info on the build site ref building a tank.
hope this helps
Woody

[s vernon]

Ballast pour

There are lots of different shaped pours. One old standby that is easy because it is flat topped is the Jordin pour. It is long and low. It is detailed in the "Manual". Any pour is determined by the placement and height of the fwd and aft dams that you afix in the boat. They can be made of plywood and if you put a gob of plumber's putty in front of the fwd one and aft of the aft one it holds them in place and seals the crack between dam and hull.

You determine the angle that the boat needs to sit at by placing a level balanced on top of the dams. Tip the boat and when the bubble is centered that is your angle. It is very steep and you will need to have the bow of the boat enclosed in a plastic bag or something that keeps water from running in. The bow will be (very close to or will be) slightly submerged during the pouring.

This is "good pour". Boats using this pour can stand up well in a breeze and go like a streak. However in mo wind and chop they will hobby horse more than other boats.

Those are the basics anyway.



Scott

[s vernon]

Kelly Martin pour

Another one - a little shorter and higher is detailed in the book "Optimizing".

I like to pour extra multiple ballast blobs using a bent up piece of metal shaped like the keel area just aft of the aft dam. So I can make various weight pieces for heavy air. 1.5 to almost 2 lb pieces might be handy.

Scott

[Larry Ludwig]

First on the test tank, we made ours out of 3/8ths plexiglass all around and then use colored templates on clear plexi set inside the water for study and measurement. It also allows for more experimental ballasting than is covered in any of the manuals. (secret stuff) [8]

The 3/8ths is the smallest I would go, and on the next tank I will go up to 1/2" just for general purposes. I made this tank large enough for 2 hulls side by side for comparison and measurement at the same time so it is holding 50 gallons and the 3/8ths has just a hint of bow in it without the external frame in place.

The 2 lbs of trim ballast is essential as that is the most common number for the amount of lead it takes to go from a 42" to 43" waterline.

Good for you guys up there in OK, keep plugging along. We are going to put Region 5 on the map this coming year. If you guys need anything you let me know.

Larry

visit us at www.LudwigRCYachts.com

[PegLeg]

The 1/4" plex is OK IF you use a 1-1/4" by 1-1/4_ 1/16th thick aluminun angle at every joint edge. Bolt the plex (with clear sealer) to the angle using #10 or 1/4" stubby bolts on about 8" centers. (we bulit ours on 4" centers and it is a real battledhip)If you do not reinforce the joints the tank will leak (at best) or fall apart.

Around the top edges the angle is "turned out" to reduce bulge, to use as carry handles and to provide a good working surface for the "string". By completely edging the tank we have no worries about cracking, leaking, rough handling or the like.

Mount a standard hose bib at one end (low on the plex) to be able to both fill and drain the tank.

Not very hard to do. If you want pictures please send me an e-mail.
[}:)]

[cshelden]

Thanks for all this info guys. I'm absorbing like a sponge. I've had one offer to send me a ballast to use as a plug and then pour them into a mold for our future builds. This sounds nice to me, but I very well may experiment with various pours. I plan to use lead shot and melt it down. Any ideas on the suitability of battery lead? I have access to several deep cycle batteries that are empty, not sure about how much of a quality lead it will make, plus the contamination of the acid, but figure any residue can be neutralized with a soda solution.

[MichaelJ2K]

Wouldn't it be easier to buy lead from sources like McMaster-Carr? I think there's some environmental issues involved with batteries. Just don't let the enviro-nazis get you. [:D]

[cshelden]

Easier? Well yes, it would be. I'm just not one to pay for everything (read not smart enough). I like to build, for me 1/2 the fun is building it. I guess I could just buy a ready made boat, but then cost is an issue. So that is where I am now, we are trying to get a fleet started here in the Oklahoma City area. We have an established Vic fleet already, so this will be the next on the water. I want to be able to show others that you can build one a little cheaper for those that like to do it your self. So for now it is a cost issue. I can buy enough lead for 3 boats at almost 1/2 the cost of a single ballast. Sorry for the short story long, I've scraped the battery idea already so no worries there.

[PegLeg]

Charlie

You might consider giving your local scrap dealer a call. Sometimes they will get a bunch of industrial lead that was used in tool hardening or similar applications. The price should be right and no enviros to worry about.

Be careful(safety) with the lead melt and pour. It can become a nasty without hardly trying. Hot lead, cold water and fibreglass certainly make a challenging opportunity.

Good luck with your fleet building. Do a great job visitors will come race with you.

[}:)]

[cshelden]

Thanks for the tip on lead, I've poured a ton of lead sinkers for fishing but never 20# at a time. I have enough for one ballast, still have one more to do. I had a generous individual send me a ballast to use as a plug and have half the mold made already tonight. I'll let it cure then do the other side tomorrow night. So I won't be pouring into the hull/tank. Test tank is still on the burner though.

Our club is hosting the Region 5 Victoria race in May 2006, after that I hope we will be ready for some EC12 activity.

[greerdr]

Tire stores give me the balancing leads-free.You have to get the attachment piece off but the price is right.

R.C.Greer

[Kent Farndell]

Bob,
When you melt the tire weights the steel clips will float to the surface and can be skimmed off. I will normally pour 1 lb ingots for future use. My only problem is when trying to pour ballast my melting pot does not have enough capacity for one boat. When remelting the ingots the sludge or impurities will also float to the surface and can be removed. I have heard that tire weights are not the most dense but is close enough for me. Unfortunately I do not remember what is more dense.
Kent

Sail #15-27/Carr sails
Hickman # 527/RMG SW280
Futaba
Kent Farndell

[RMDJBD]

BOB
TIRE WIEGHTS ARE ONLY 50-65% LEAD, THE REST OF THE WEIGHT IS TIN AND ANTOMONY WHICH MAKE THEM HARDER, BUT MAKE THEM APROXIMATLY 30% LIGHTER. YOU CAN GO TO A PLUMMING WHAREHOUSE AND BUY VIRGIN LEAD IN 5lb INGOTS FOR ABOUT .75 CENTS A LB. TODAYS LONDON EXCHANGE LEAD IS .46 CENTS A POUND. I BUY MY LEAD AT GULF COAST LEAD IN TAMPA .62 CENTS PER 100 POUNDS. ANOTHER PLACE TO GET PURE LEAD IS A R00FING SUPLY HOUSE, YOU CAN GET LEAD FLASHING OR STACK BOOTS, THESE ARE PURE LEAD. HOME DEPOT AND LOWES HAVE STCK BOOTS TOO.

Bob Dudinsky
R.M.D.MARINE