Sam Clemens worked on steam boats. I am not sure he ever received a license to pilot them. If that is what you are asking the answer is none.
BUT!
Isaiah Sellers was a steam boat captain. One of te Mississippi's finest we are told. He is credited, by S. Clemens, to be the first person to use the name Mark Twain as a writer.
He was a captain on the Mississippi for many years.
HOWEVER!
No record of any of his writing being publish are around any longer.
Did I add any mud to the clarity you were asking to obtain on this question?
Mark Twain served as an apprentice pilot on the Mississippi River for about two years.
Mark Twain served as a pilots apprentice for two or two and a half years.
he worked as an apprentice for about two years
two or two and a half years
They are called Pilots. They are extremely knowledgeable on the area in which they work and how the water affects the ship. They typically serve as an apprentice under a qualified pilot for a fairly long time.
Mark Twain lived until he was 75.
The word "pilot" has a long vowel sound for the letter "i," pronounced as /aɪ/.
The 2011 Honda Pilot is 15 ft 10.9 in long.
She was a pilot for 16 years.
The I in pilot has a long I sound, as in the word pile. The O has a schwa sound.
an hour and 51 minutes
a million years :(
6 moons.
Glade is a long vowel because as they say to the younger children the "a" is bossy but every magician needs an apprentice and the "e" is the apprentice.
mark twain
He was an apprentice for a half a book,cause he and Graystripe both became warriors in the first book.