Raymarine 465 - Manual (Page 103)

92 Glossary
Glossary of Terms
Aft: Near or toward the rear part of the boat (nautical term).
Background noise: False or meaningless echo returns produced by
bubbles, water turbulence, or debris
Bow: The front of the boat (nautical term).
Cavitation: Air bubbles in the water which affect the readings of a
transducer. These are normally caused by mounting the
transducer at an incorrect angle or location.
Chart Speed:The rate at which echoes scroll across the display.
Cursor: On a setup display, the place where the unit is ready to make a
change or enter new information. This point is highlighted. You
can move up or down the list or display using the and
controls.
Deadrise angle: The slope or angle of the underside of the hull, mea-
sured in the side-to-side direction.
Default value: A value or setting which is pre-loaded into the unit at the
factory.
Fairing block: A block used when mounting a thru-hull transducer. The
fairing block shims the transducer to align it on a perfect
horizontal plane versus the rise of the hull.
Fathom:A unit of depth equal to 6 feet.
Frequency: The rate at which a sound source vibrates, or the rate at
which a sound wave changes.
Fore: Near or toward the front part of the boat (nautical term).
Keel: The center of the hull, running from the bow to the stern.
kHz: “Kilo-Hertz” – a measure of frequency (For example, 200 kHz =
200,000 oscillations per second.)
Kick-up bracket: A bracket which is installed on the transom of a boat
and holds the transducer in place. When the transducer strikes
an obstruction, it is designed to release or “kick up” out of the
water to prevent any damage.