Who is Tiny Colleto and Sparky Enea from The Log from the Sea of Cortez and what is their importance?

Tiny Colleto is a seaman on the three-person crew of the Western Flyer. He is hired in Monterey. Tiny and Sparky grew up together and were good-natured trouble-makers during their youth. They are presented as inseparable and almost interchangeable, doing the same things at the same time and generally having the same approach to life. Both men are avid and successful fishermen, providing fresh fish to the expedition while in Mexico. They pay less attention to navigation, particularly, if they are occupied by fishing. Thus, the boat tends to go off-course during their watches, which they always take together.