Speaker 1: Welcome to brain Stuff from house stuff works dot com
Speaker 1: where smart happens. Hi. I'm Marshall Brain with today's question,
Speaker 1: what is a semi submarine? So we've all seen submarines,
Speaker 1: and almost always their military submarines, and there's a reason
Speaker 1: for that. Submarines tend to be quite expensive. There's two
Speaker 1: reasons why they're expensive. First, any sealed container full of
Speaker 1: human beings presents problems. You have to deal with the
Speaker 1: oxygen supply. You have to deal with this carbon dioxide removal,
Speaker 1: and you have to worry about humidity from the error
Speaker 1: that we exhale from our lungs. So it takes a
Speaker 1: fairly precise system to keep the oxygen level at about
Speaker 1: You have to have chemical scrubbers that remove all the
Speaker 1: carbon dioxide, and you you need to do something with the
Speaker 1: humidity or you get all this condensation on the inside
Speaker 1: walls of your submarine makes a mess. The second reason
Speaker 1: why submarines tend to be expensive is that when you
Speaker 1: stick that sealed container underwater in the form of a submarine,
Speaker 1: the problems multiply. You have to deal with water pressure now,
Speaker 1: so the container, including its windows, has to be strong
Speaker 1: enough to handle depth and it doesn't take much depth
Speaker 1: to create a lot of water pressure, and then you
Speaker 1: also have to worry about how you're gonna dive and surface,
Speaker 1: So you have to have ballast tanks, and you have
Speaker 1: to be able to fill those tanks with water or
Speaker 1: blow the water out of them. And you have to
Speaker 1: make your container completely leak free, obviously, and that's not
Speaker 1: a simple thing, especially if you're gonna put windows in it,
Speaker 1: and that's why a lot of military submarines don't have
Speaker 1: any windows at all. So what's the solution. What if
Speaker 1: you would like to create a submarine, but you'd like
Speaker 1: the lower the costs so that normal people can afford them,
Speaker 1: One thing you could do is you could eliminate the
Speaker 1: sealed part of the container. Second, you could eliminate the
Speaker 1: problems with pressure by controlling how deep your submarine can
Speaker 1: go and keeping it really shallow. And third, you could
Speaker 1: eliminate the need for diving and surfacing, and therefore you
Speaker 1: can get rid of all the ballast tanks and blowing
Speaker 1: the tanks and everything that has to go with that.
Speaker 1: Almost all the problems go away if you start putting
Speaker 1: these constraints on your submarine. And that's the idea behind
Speaker 1: a semi submarine. A semi submarine lets you, as a passenger,
Speaker 1: ride around underwater, but the depth is very limited. It
Speaker 1: might be six feet at most, and the submerged part
Speaker 1: of the submarine remains open to the air above, so
Speaker 1: you don't have to worry about pressurizing the container or
Speaker 1: keeping the leaks out like you do with a submarine
Speaker 1: that goes down a hundred feet. So here's one way
Speaker 1: to think about a semi submarine. Think about creating a
Speaker 1: small room. Say the size of a closet. It might be,
Speaker 1: you know, four by four ft or four by six
Speaker 1: ft or six by six feet in size, and it
Speaker 1: might be six x or eight feet tall, just like
Speaker 1: a normal closet in your house might be. You make
Speaker 1: that closet out of a sealed container, either out of
Speaker 1: fiberglass or out of steel, and you put great big
Speaker 1: windows in it so that you can see out. Those
Speaker 1: windows don't have to be exceedingly thick, because they're never
Speaker 1: gonna be much more than six or eight feet underwater,
Speaker 1: So you might make them an inch or an inch
Speaker 1: and a half thick if their glass maybe about the
Speaker 1: same if they're made out of acrylic. Now you put
Speaker 1: a couple of comfy chairs in this closet so you
Speaker 1: can sit and look out the windows. And now you
Speaker 1: just have to get this closet submerged in the water
Speaker 1: so that it's underwater but won't sink. And the most
Speaker 1: common way to do that is to put some kind
Speaker 1: of pontoons on top of the closet that will keep
Speaker 1: the top of the closet up out of the water.
Speaker 1: That is the basic configuration for some semi submarines. And
Speaker 1: then you put a couple of electric motors on them,
Speaker 1: or a little um gasoline motor or something so that
Speaker 1: you can move it around through the water. And if
Speaker 1: you're in a nice clear water, say around a coral reef,
Speaker 1: you can paddle around with this with this floating closet underwater,
Speaker 1: and you can see all kinds of stuff because the
Speaker 1: water is nice and clear. You can look and see
Speaker 1: the reef, you can see the fish swimming around the reef,
Speaker 1: and so on. Without ever getting wet, and without ever
Speaker 1: having to worry about scuba equipment or snorkels or anything
Speaker 1: like that. You simply sit in your comfy chair, you
Speaker 1: look out the window, and you steer the boat around
Speaker 1: with some simple steering mechanism. Typically you find semi submarines
Speaker 1: in resort areas. So if you go to Hawaii, for example,
Speaker 1: you can find semi submarines that hold thirty or fifty
Speaker 1: people and you go down below and you're about six
Speaker 1: or seven feet underwater, sitting on a bench or a
Speaker 1: chair looking out great big glass windows that are an
Speaker 1: inch and a half thick. Or you can go to
Speaker 1: resort areas and find little two persons semi submarines that
Speaker 1: you can tool around with on your own. Semi submarines
Speaker 1: were invented in the nineteen nineties and they've been pretty
Speaker 1: popular since their invention. They're popular anywhere where you would
Speaker 1: find things like glass bottomed boats. Be sure to check
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