1.2.2 Parts of the Boat
Parts of the Boat
Whether you're a passenger or the operator, knowing your way around the boat and understanding common nautical terminology is a fundamental skill that starts with establishing and understanding basic marine or nautical vocabulary. As shown in the diagram below, the terms bow, stern, port, and starboard are used to designate the four primary orientation points within the boat (front, back, left, and right).
The term forward or ahead refers to the direction towards the bow, while aft or abaft refers to the direction towards the stern.
This terminology is also used to describe positions outside of the boat. For example, a position in front and to the left is referred to as "off the port bow." Any position behind the boat is referred to as astern.
The largest and most prominent part of most vessels is the hull (the boat's outer shell). The flat surface that runs along the top of the sides is the gunwale (sometimes spelt "gunnel," it rhymes with tunnel). When the boat is floating freely, the vertical distance from the waterline up to the lowest point on the gunwale is called the freeboard.
Most vessels have a structural member called the keel that runs the length of the boat along the centreline of the bottom of the vessel. The vertical distance from the waterline down to the deepest point on the boat, whether that be the keel, the bottom edge of the engine drive system, or the lowest point of steering (rudder), is called the draft.
Draft and freeboard are more than definitions to be memorized for a test. They are two of the most important characteristics of every vessel while afloat. Draft dictates the minimum depth of water the boat needs to float without running aground. Freeboard indicates the height of a wave (natural or from the wake of a passing vessel) that will spill over the gunwale and enter the vessel's hull.
Because draft and freeboard are both measured from the waterline, both change when the load in the boat increases and the boat sits deeper in the water. Draft increases (meaning you need deeper water to avoid running aground) while freeboard decreases (meaning a smaller wave can overflow the gunwale). These changes make the vessel more vulnerable (easier to run aground or easier to become swamped), so staying aware of your freeboard and draft is an ongoing task for every boat operator.