Newbie >> Trim And main ballast Questions?

[doc]

HI All although it will be a while before i get to my ballast systems, what is the general rule of thumb if there is one?? Do you flood main ballast to get neutral boyency thin trim>> or vent trim tanks 1st Then main ballast and add or remove with the trim tanks to get a Balance when submerged?? Iwas planning on useing lead in the main keel section as hard ballast to get the proper Draft height. Doc

[jodyae52]

Trim and Main BalLast Questions

This would make an excellent topic for those more experienced builders to share at the Sub Regatta!

[Wheelerdealer]

It depends on what type

It depends on what type of trim tanks you have. Are you shifting ballast between the 2 (total ballast always constant- just making the sub sub bow or stern heavy) or do you have independent trim tanks? If its the former, I would then simply ballast the sub so its neutral or as close at with the main tank full and simply move water between the two trim tanks till level the boat. If you have independent trims (say piston tanks), then ballast the sub to be neutral with the main ballast tank full and the trims at 50%.

[doc]

I was planning on useing

I was planning on useing indipendant trims frnt and rear because of the size of my build, and useing free fill and CO2 Blow on all Three. Idealistically i wanyed to use the saddle tanks of the type VIIC for the mains, which is the reason i thought id flood the Trims 1st so as to allow for more low end weight stabillity. Doc

[Guest]

Unless you're using piston tanks,

Unless you're using piston tanks, which enable proportional control, forget the idea of using twin tanks, you'll let yourself in for a world of pain.

Instead, use a centrally mounted tank, and then build your battery pack onto a sliding tray. Couple this to a servo to allow 1-2" of movement. This will give you a trimmable ballast system that is completely proportional.

Simple, cheap, effective.

Andy

[doc]

Good food for thought Thnks

Good food for thought Thnks guys!!

[doc]

I like the single tank

I like the single tank idea with movable tray, my thought now is to make my end caps of my main tanks with a 3/4 sphere leaving the top of the tank Flat. Ill probably have to run 12 volts possibly with two batts 6V in series one mounted on the outside of tank on each end low in the hull for balance. build a rail slide to sit on the flat top of the tank with a weight that can be adjusted bow and aft . This will also leave me with an air tight compartment to run wiring ect To and aft over the ballast tank. Like you said , this already sounds more simple>>> ( I like simple!!) Doc