xPooRLoCKerBoYx

I hope im posting in the right place, (just made this account) but im looking to build a RC Nitro boat and considering i dont want to swim for my boat if i run out of feul(and this idea is pretty cool!) i want to find a way to have 2 gas tanks on a servo switch? kinda like an old truck where u can choose witch tank u want to use! If its just a switch im sure i can find a way to rig it with a servo. this boat im gonna be building will be quite big so i kinda have room to work with!

1QwkSport2.5r

You will be hard pressed to find a method that will work for what your intending to do. That is, something with redundancy. If your servo or tank switching valve fail, you're still gonna have to retrieve the model. Even if you do find a way to make it work, you're introducing several points of possible failure (leakage of fuel and/or air) in the system. An engine can only perform properly if the fuel system is sound. In a radio controlled environment, you want as few points of failure as possible. The solution is to use a larger fuel tank. It helps to do baseline testing to determine how much fuel the engine consumes in a given amount of time and basing your fuel tank size on that. I run boats myself and I have determined that too much fuel adds extra unnecessary weight and too little fuel makes for short run times. I have however never ran out of fuel in my boats. I keep an eye on the fuel level and when low I bring it in for a refill. I find there are other variables that will create a "retrieval mode" like weeds on the rudder or prop, floating debris, animals, etc.

You could certainly make it work but I don't see the effort paying off when you can just use a bigger fuel tank. If the off-the-shelf offerings aren't large enough, you can use old soda bottles, baby bottles, medical IV bags, and the like to accommodate the capacity you need.

Just my opinion, take it with a grain of salt.