Ahoy there, Twisted! You're in luck. There are a number of active battlers in Florida. In case you haven't noticed, this particular forum isn't heavily used by RC combat skippers. I would highly recommend that you introduce yourself on the [link=http://www.rcnavalcombat.com]RC Naval Combat website and forum[/link]. This will put you in direct contact with battlers near you, so you can go visit their battles and see them in person. Attending a battle in person is the BEST way to get started in this hobby. It lets you see a bunch of ships and how they work, see how combat actually works in real-time, and answers far more questions than you could possibly write in email. If a picture is worth a thousand words, attending a battle in person is priceless.
That said, I think I can answer your question and clear up a misunderstanding. RC combat warships don't use depth charges, they use cannons. These cannons are powered by CO2 or compressed air, and fire steel ball bearings ranging from .177" diameter bb caliber up to 1/4" (0.25") diameter at low velocity. They have enough energy to punch through the soft balsa sides of another RC combat warship, but not enough to seriously harm a human, as long as he remembers to wear his SAFETY GLASSES. In case you haven't noticed we take safety very seriously in this sport, and I'd like to make sure you do the same.
RC naval cannons can be built from a variety of materials and parts, ranging from brass and copper plumbing fittings at your local hardware store to custom-machined PVC, brass, and aluminum. They look like this:
[link]http://i65.photobucket.com/albums/h237/kotori87/Image135.jpg[/link]
[link]http://i65.photobucket.com/albums/h237/kotori87/Image136.jpg[/link]
[link]http://i65.photobucket.com/albums/h237/kotori87/IMG_9014.jpg[/link]
The basic operating principle behind an RC naval cannon is very simple. You take gas from a regulated source of pressure (CO2 bottle plus regulator), and store it in a large volume tank called an accumulator. When you're ready to fire, you open up a high-flow air valve that dumps the air behind the ball, pushing it out the barrel and towards the Dastardly Foe(tm).
[link]http://i65.photobucket.com/albums/h237/kotori87/CannonDesign101.jpg[/link]
This is how spud guns work on a larger scale. However, RC naval cannons, unlike spud guns, need to reload by themselves. To do this, we battlers have invented a zero-moving-parts breech mechanism. It looks like this:
http://i65.photobucket.com/albums/h2...lessBreech.jpg
A ball drops into the breech from the magazine, pushed there by gravity. A second ball rolls up right next to it, slightly obstructing its path out the barrel, again via gravity. When you fire, the fast-moving pressurized air forces the loaded ball up and towards the 90degree bent barrel. This pushes the next ball back towards the magazine, thereby preventing the cannon from spraying an entire magazine's worth of ball bearings like water from a hose. Multi-barrel cannons simply gang several of these mechanisms together. Rotating cannons simply rotate the breech and magazine, while leaving the accumulator fixed below.
As for where to get cannons, you can get them from [link=http://www.strikemodels.com]Strike Models[/link]. They carry single-barrel cannons, and are currently developing multi-barrel rotating cannons for mass production. If you don't want to wait for multi-barrel rotating cannons, however, you will need to make your own.