Okay, so, you've been tooling around the ocean in your whaling ship, and you climb up into the crow's nest, and you actually spot a whale. Now what do you do?
This is the crazy part: You, and a bunch of other guys, get off the nice, big whaling ship, and climb into this tiny little boat. These longboats are about sixteen to twenty feet long.
And then you row as fast and quietly as you can out to where the whales are. You are in the middle of the ocean, in a very small, very crowded boat. The whale is about the size of a city bus, and sperm whales are every bit as aggressive when protecting their own as any other mammal. So what do you do? You start jabbing them with pointed sticks.
Once you harpooned a whale, it would take off. Your boat would still be attached to the harpoon by rope, and so you'd take off, too. At high speed. This was called a "Nantucket Sleigh Ride," and they could last for days. And the whole time, you're hanging on just hoping that the whale doesn't remember that it's a whale, and whales can swim underwater.
Just how badly did the world need lamp oil and corsets, anyway?