Next we will find out who the other two "mates" are -- second and third assistants to the captain -- and who their assistants might be. This has important implications for the command and operation of the whaleboats which are lowered from the mother ship to attack the whales. Usually, it is a mate (rarely a captain) who starts out standing on the stern of the whaleboat, commanding the oarsmen and steering the boat to the whales with a long steering oar. As boat commander, the mate is the "headsman", not a public executioner who beheads people -- but whales beware! [Note - a speculation on steer by the stars: the German word for stars is sterren (whence, stern from sterren? -- much the same as the Old English word) -- the steering oar was once the steering board -- or star board -- the side you steer from with your right hand (lefties excepted). So -- if the steering board was on the starboard side, then you had to bring the boat up next to the wharf on the other side -- the port side!]
There are typically five oarsmen under the headsman in a whaleboat. The oarsman in the bow of the boat is the harpooneer -- he whose job it is to stick the sharp-pointed arrow-headed iron spear into the body of the whale to "fasten" to it (it's a huge fish hook, if you will). After a "Nantucket sleigh ride" (about which, more later), the mate and the harpooneer trade places, so the mate as headman in the bow can get the honor of dispatching the whale by driving a long lance into the whale's "life". At this juncture, the harpooneer has wound up at the stern, where he mans the steering oar, so he is also the boat-steerer!
We learn that Stubb is the second mate of the whaleship Pequod. A native of Cape Cod (and the brother-in-law of Aunt Charity and Captain Peleg back on Nantucket), Stubb is a "happy-go-lucky". A supposedly good-humored man, he handles his lance cooly, actually humming a tune while killing a monstrous, furious whale. If Queequeg is characterized by the putting on of his tall beaver hat first upon arising, then Stubb has the distinction of putting a short, black little pipe in his mouth upon rolling out of the bunk. We further learn that Flask is the third mate. A native of Martha's Vineyard, he is described as a short, stout, ruddy young fellow -- nick-named King-Post, after a short, square timber on a whaleship. He was a fearless, irreverent killer of whales. Now each of the mates, Starbuck, Stubb, and Flask had his own harpooneer / boat-steerer. It was Starbuck's good fortune to have selected our old friend Queequeg as his harpooneer.
Melville populates the Pequod with representatives of the ethnic groups of the world that found themselves under the command of the white Christian captains and mates of New England whaleships. Queequeg, we know, is a South Sea Islander. Next is Tashtego, a pure-blooded Indian from Gay Head on Martha's Vineyard, a traditional supplier of Indian whalers to neighboring Nantucket. He belongs to Stubb's boat as the harpooneer. Third is Daggoo, "a gigantic, coal-black negro-savage" for Flask's boat. Mention is made of natives of the Azores Islands -- best whalemen are from islands -- and black little Pip of Alabama.