It is a very large red and dark navy-blue boat that has two steam-powered turbines, generates 6500 horsepower, and is geared up to triple screws. The ship's name is painted on the stern and it carried exotic spices from faraway lands.
Role in episode
When Mrs. Puff and her class go for a field trip, they visit the Bikini Bottom Museum of Boating, in which there is the Sandy Nub. SpongeBob seems to know a lot about this boat, since he studied all night to impress Mrs. Puff.
The name Sandy Nub is painted on the ship's stern. Usually, a ship's name is painted on the bow.