R/C Naval Combat

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Originally posted by Craig

Yes those would be. What if you put them equally on either side of the exterior hull?

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They would get shot during battle...

Even if the gauge of rubber was higher? Like bike tire thick? What about putting the ballons in the superstructure?

You also have to remember that the deeper the water, the more pressure you'll need to displace the water. At 10 foot depth, you have to over come an additional 15 psi (in addition to 15 psi from air pressure). So thats a factor of 2.

Andy

Balloons will get shot in the superstructure and odds are it will rip the structure off if the balloon inflates there and tries to lift the weight of the ship.

Curt, don't tell him! I want to see pics after he tries it!! 8)

You would Tuggolas you would! Well, then we've exhausted this plan... unless someone has a better idea... I'm thinking maybe a cannister with the substance used in the Zeppelins.... hmmmmm... leave it with me....

So if I am the handsome Tuggolas, does that make you Craigli of the dwarves? 8) Glee!

You're going to have to toss me! Don't tell the elf.... :)
Someday we two great combatants will sail together to wreck havoc and have great glory on the ponds, lakes, rivers and streams.. wherever the enemy might be found....

I wonder if a unique onboard system would be the eye of Sauron? I could shine it into the apposing captains eyes while combating. I wonder if I would have it stationary as in FG or rotate like BG....

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Originally posted by Craig

I wonder if I would have it stationary as in FG or rotate like BG....

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That's hilarious!

Actually, as any scuba diver knows, after you inflate the "lift bag" to lift the ship you need a way to vent the expanding gas or your balloon will pop. Possibly get those balloons made created for balloon animals. Those seem to be very stretchy and expand easily. If popping continues, get more balloons.

Pirates or Ninjas....Thats a hard one.

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Originally posted by donanton

Actually, as any scuba diver knows, after you inflate the "lift bag" to lift the ship you need a way to vent the expanding gas or your balloon will pop. Possibly get those balloons made created for balloon animals. Those seem to be very stretchy and expand easily. If popping continues, get more balloons.

Pirates or Ninjas....Thats a hard one.

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My Dad's been a Shrine clown for many years & uses hundreds of those balloons. They come in different grades. All are extremely tough, & take a lot of air power to blow up compared to your basic toy store balloons. They don't expand easily at all, & some of the older clowns have to use pumps to blow them up, but that might make them usable as suggested.

JM

How about a flaming magnesium strip launcher?

Stu

How about something like an air bag in a car? It would have it's own little gas charge. & you have it stuffed in one of your smoke stacks, & you just hit the button & it blows out the stack.

lift bags and venting depends on depth. If you are sinking in shallow water say under 10-15 feet of water venting will not be needed. the key is to figure out how much lift you will need the find a blatter / bag that will give you the amount of lift also the ammout of air /co to lift it. why not use and extra channel and co from you cannon supply that way you can control the amount of gas used.

Bouyancy depends on depth. So find out what depth and somehow find out how much lift you need since you need more the deeper you go.

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Originally posted by donanton

Bouyancy depends on depth. So find out what depth and somehow find out how much lift you need since you need more the deeper you go.

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Not really, bouyancy is density dependent, depth really has nothing to do with it. If the weight of an object is less than the weight of the fluid it displaces fully submerged it will float, otherwise it will sink. The amount of water that one of our boats displaces is equal to its weight, as the boat gains weight (water coming in through holes) it must displace more water to remain afloat so it sits lower in the water, increase the weight enough and it sinks.

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Originally posted by SnipeHunter

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Originally posted by donanton

Bouyancy depends on depth. So find out what depth and somehow find out how much lift you need since you need more the deeper you go.

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Not really, bouyancy is density dependent, depth really has nothing to do with it. If the weight of an object is less than the weight of the fluid it displaces fully submerged it will float, otherwise it will sink. The amount of water that one of our boats displaces is equal to its weight, as the boat gains weight (water coming in through holes) it must displace more water to remain afloat so it sits lower in the water, increase the weight enough and it sinks.

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Not *technically* correct. When water leaks into the ship, either through damage or otherwise, that's water that the ship is NOT displacing. It still weighs the same, but in order to keep the same displacement, it must float a little lower in the water. For all practical purposes you're right, but if you really want to be specific about it, then that's how it works.

One more thing. Buoyancy depends on displacement, and the displacement of an object can change with depth. Take, for example, a ziploc bag full of air, with slightly positive pressure above the water. When you put this bag in water, the water exerts a pressure on it, and the air inside resists this pressure. The pressure of the air inside will increase to match the pressure of the water outside. If you increase the pressure outside, the air inside will compress and the displacement will shrink. I saw the same principle in action at an underwater ROV competition in Texas, when several teams used the squishy foam from "noodle" pool toys to adjust the balance of their robots. They were neutral buoyancy when surfaced, but once they got down 20-30 feet, the foam compressed to half its usual size and the robots were no longer at neutral buoyancy. One of these teams sank so fast that their ROV crushed and disintigrated the sensor package it was supposed to deliver when it hit the bottom.

If you were to calculate the pressure you would encounter at the depth of water you will probably sink in, you could then set the gas pressure inside your inflatable bag to something slighly higher than this. Just be sure the bag is capable of containing that much pressure when surfaced, or it'll pop halfway up and you'll have to go swimming.

Both of our statements are true, the difference is how we define the control volume that is the boat and stuff inside it, but you're right that it works out the same (as physics should) so its all good.

You're right that pressure increases as you go down but at the depths we sink at its not very much, less than a 3 psi increase at a depth of 2 meters. I would imagine a mylar balloon could handle that, but who knows.

Still it would be cool to watch a submerged warship driving back to port with just some lift bags touching the surface. Not sure the best way to deploy them so they dont go accidently if your radio glitches, maybe some sort of pressure switch that would only go if it was more than X deep.

I prefer to sink in shallow water, thats easy enough.

Nah, just have a 10' antenna with one end attached to the reciever and one end hanging out of your float. Use that extra channel to open a solenoid and voila. Float on command.