Submarine Coloring Page: Free Printable PDF for Kids

Submarine: History & Fun Facts

Early Attempts at Underwater Travel

Dutch inventor Cornelis Drebbel built one of the first working submersibles around 1620, rowing an oar-powered wooden hull beneath the surface of the River Thames in front of King James I. It would take another two and a half centuries of trial and error before submarines became reliable enough for military and scientific use.

A Confederate vessel called the H.L. Hunley became the first submarine to sink an enemy warship in 1864, though it went down shortly after the attack and wasn't recovered from the seabed off Charleston until 1995. Its crew of eight cranked a hand-turned propeller shaft for hours at a time, a stark contrast to the electric motors that power the rounded hull pictured in this scene.

The Periscope and Diving by Ballast

A submarine dives and surfaces by controlling ballast tanks built into the hull - flooding them with seawater makes the vessel heavier and it sinks, while pumping the water back out with compressed air makes it float again. The periscope on top of the conning tower uses a set of angled mirrors or prisms so the crew can see the surface without exposing the hull.

Trim tanks fine-tune that balance once a sub is already submerged, letting the crew hover at a chosen depth without constantly rising or sinking. Ballast control got much more precise once engineers switched from manual valves to computer-assisted systems, though the rear propeller shown behind the conning tower still works the same basic way it did a hundred years ago: it spins to push water backward and shove the hull forward.

Nuclear Power and the Century-Long Dive

The USS Nautilus became the world's first nuclear-powered submarine in 1954, and it later became the first vessel to cross the North Pole while fully submerged beneath the polar ice cap in 1958. Nuclear reactors let a submarine stay underwater for months at a time instead of surfacing every few hours to recharge batteries and refill air tanks, since the reactor also powers systems that pull oxygen straight out of seawater.

Diesel-electric submarines, smaller and quieter than their nuclear cousins, still patrol coastal waters for many navies around the world today. Both types rely on the same porthole-and-hull silhouette that shows up in classic submarine art, a shape that hasn't changed much since it was first perfected for stability underwater.

Submarines in Modern Ocean Science

Modern research submarines and submersibles now explore ocean trenches more than six miles deep, far beyond where sunlight reaches, mapping seafloor terrain and studying deep-sea creatures that were unknown before undersea travel became possible. The same basic hull shape and porthole windows shown in this scene have stayed useful for over a century of underwater exploration.

James Cameron piloted a submersible called Deepsea Challenger to the bottom of the Mariana Trench solo in 2012, reaching a depth of nearly seven miles where water pressure is more than a thousand times what it is at the surface. Seaweed forests like the ones drawn along the ocean floor in this picture only grow in much shallower water, usually less than 100 feet down, where sunlight can still reach the seafloor for photosynthesis.