Why did the us build up and modernize its navy in the late 1800s?

Answer 1

For the same reason we maintain the strongest Navy on the planet today - we are a Maritime nation that depends on strategic minerals and other imports that are not found within our borders to survive. Those materials are brought to our shores by merchant vessels around the world. This is why the U.S. reacts so forcefully whenever areas of instability around the world threaten our strategic interests.

In the 1800's as a fledgling nation, we were not the huge nation we are today. Early in the 19th century, much of the nation remained unexplored, and the materials we needed and trade goods came from Europe and other countries. Protection from pirates and other belligerents was a major priority then just as it is today. The other reason is that in the 1800's the only way most people got to our shores was by ship - Mexico and South America weren't as developed as Europe was, and any enemy would come by ship (e.g., the British). Even if they landed in Canada, as in the French-Indian Wars in the 18th century, or if they landed in Mexico and worked their way north, they would still come by ship to get there. It was not just The Revolutionary War that taught us that maintaining a strong Navy was a vital aspect of survival either. Remember that in those days, most sailors in the Continental Navy and the early American Navy were former British sailors, and Naval Officers were once a part of the British Navy as well. We are descended from another major maritime nation, Britain, and our nation's architects were once British subjects. Don't forget how the U.S. came to be. Everyone involved in the creation of the United States understood the value of a strong Navy then, just as we do today. Our historical ties with Britain are the reason we have remained close allies for many years.

Over the years with different wars, Naval operations and tactics have changed as warfare has changed. WWI showed the viability of the Aircraft Carrier and Submarine; WWII proved it, and Carrier development also proved that the Battleship, once the premier ships of the line, were obsolete as Naval aircraft could cause more damage from accurate bombing when fleets weren't even in visual range of each other, something that surface combatants needed to fight each other. The first major test of this was the Battle of the Coral Sea in WWII; it was the first Naval battle fought entirely by Naval aircraft. The opposing fleets never saw one another.

In today's times, many people are under the misconception that the U.S. is only interested in oil because of cheap gas. Nothing could be further from the truth. Merchant ships depend on fuel to operate, and without those ships being able to operate freely on the high seas, the materials we need to survive as a nation would not be able to get to us. Or worse, if a nation with an unstable or hostile leadership were to gain control of strategic areas (like the Middle East) they could literally blackmail us or cutoff the very materials we need to survive, and our allies as well. As a nation, letting someone gain that kind of control over us is unacceptable, and is the primary reason we maintain a strong Naval force.

Carrier Battle Groups are particularly used to move US power into regions of instability, as just one CBG has enough power to destroy most enemies. They have for decades been used as an effective instrument of both deterrence and foreign policy.

Answer 2

The U.S. wanted to have a stronger international influence and oversea markets, and the only way to enforce markets was with the navy.