It is named that because the top of the sub looks like a turtle's shell.
Turtle
The name of the turtle is Crush
Proper nouns are names - either of people or of places. Unless you have someone or somewhere named "Turtle" then it is not a proper noun.
The sea creature named after Steinbeck is the Steinbeck's softshell turtle (Apalone spinifera stejnegeri). It is a subspecies of the spiny softshell turtle found in the United States.
yes, she is named after the statue, she appears in the Next Mutation series.
david bushnell
The first submarine looked like an egg pointing upwards. It had a window in front and had robotic arms to attach bombs to warships. It was named as "the Turtle".
turtle
David Bushnell created and used the Turtle
1776
The Turtle was brown.
The Turtle was made mostly of wood, with a few metal parts.
It was invented by David Bushnell.
Turtle
It was a submarine in World War 1 or 2
David Bushnell
The first submarine was the Turtle during the Revolutionary War. It was a sphere essentially.