Directions
On a sailboat, different terms replace everyday words, permitting sailors to be more specific about the directions they should take. For example, the right side of the boat is known as the starboard side, while the left side of the boat is known as the port side. The front of the boat can be called either forward or fore. The back, or rear, of the boat is known as the aft. Similarly, the bow is the front part of the hull and the stern is the back part of the hull, while the widest part is called the beam.
Spars
Spars, or beams holding the sails, are important to correctly identify for the new crew member to understand his captain's directions. The vertical spar on a boat is called a mast. The horizontal spars can be divided into two categories. Those low enough to hit the sailor are called booms, those too high to reach without climbing are called gaffs, while those in between are called poles.
Rigging
The devices on a boat used to control the ropes are called rigging. The rigging used to raise and lower the sails is called running rigging, while standing rigging supports the spars. Becoming familiar with these terms can help you understand your captain's instructions as you learn which rigging controls which ropes, or lines, as they are known onboard.
Ropes
In general, "rope" is never used to describe part of a boat, for onboard it is known as a line. If it is a thick line, it will be called a cable. Lines can be attached to sails, making their shapes different, in which case the sail is known as a sheet.