Examples of appliances I want to protect are: monitors, computers, and printers.
I have looked everywhere and I cannot find a solution where I can simply buy a box in the market. These are often times very small and will not fit the appliances I need to be protected.
Assumption is that the container will be used for home use in case there is a great flood. So the water pressure isn't likely to be too strong--not like submarines where they dive down to deep altitudes.
I can say that a submarine is a massive watertight container that can allow many people and equipment to live inside it. So, creating a watertight container should be possible with similar concepts. I wonder what materials and techniques I should look into to build one myself.