One of the things I got to see while on vacation was the Bath Iron Works in Maine, from a boat on the Kennebec River. We got to see one of the new Zumwalt-class destroyers as it was being finished up with an Arleigh Burke-class destroyer on a floating drydock next to it and learned that the drydock is used to launch ships from the works nowadays. And that seems so anti-climatic, especially when you look at the land that used to be the Percy and Small shipyard (now, the Maine Maritime Museum, where our tour started and ended) and you see the two slips where ships would be built before being slid into the water on greased tracks. You can get an idea of what a large schooner looks like going tail-end first into the water for the first time, but for sheer visual impact, nothing beats a side launch.
Basic science: a ship floats the mass of the water moved equals the weight of the ship. Look at anything that is classified as a “ship”, and try to guess a weight. Want help? The ship I traveled on recently, M/V Grandeur of the Seas, is 73,817 gross tons or 44,122 net tons. Guess what that kind of weight does when it rudely shoves water out of the way on launch?