Key word is "ECONOMICAL". Tug draws less than 1 amp. Just over 2 amps with upgrade. Tow draws less than 2 amps. Duck less than 1 amp. Crackerbox draws the most at around 12 - 15? amps depending on your battery/motor/prop combination. I'm always swapping electronics from one boat to another. I recommend that you buy an ESC that will work on scale or fast electric. Some ESCs don't run scale boats very well. Those I keep in my FE boats and put what works in the Scale models.

Boat ESCs are generally waterproof, although some can be damaged with prolonged immersion as water can flow between the wire and their insulators into the sealed ESC in time.

Car ESCs are more widely available. If they get wet, they must be disconnected, opened up, rinsed, and completely dried as soon as possible to avoid damage. Prolonged immersion under power will usually kill them due to corrosion of the circuit board from power flowing through water between components. Short immersion may kill them if you continue to run the boat while the ESC is wet. A loss of control of the motor will result from a wet ESC.

Avoid ESCs that are labeled "with brake", "brake-on" or have language that talks about brake amps. With some car ESCs, reversing the trigger causes the car to brake. Farther you push the transmitter's throttle trigger, the harder the braking. To reverse, you would have to return the trigger to neutral then back again to engage "reverse". When you let someone run your boat, in a panic stop, they won't remember to toggle reverse twice to make it reverse and they will crash into the rocks, friend's boat, etc... Some ESCs have a programmable brake function that you can turn off.

Electrical insulating coating/lubes are available to spray/coat car ESCs before they get wet. These usually void the warranty of the ESC. Getting the ESC wet voids the warranty as well.

Best insurance is to wrap the ESC in a paper towel, then cover with a balloon or the finger of a rubber glove with a tight twist-tie where the wires exit. This way, if some water gets by the twist-tie, the paper towel will soak it up keeping small amounts out of the insides of the ESC. If you know the boat is going to get wet inside, then squirt some sealant, caulking, or grease around the wires where the balloon will be tied, and tie with several wire ties or a nylon pull-tie.

After a day of running, open up the balloon/glove-finger to let the ESC air out incase some moisture entered the assembly.

I recommend you do the same thing with your radio receiver.