Difference between revisions of "AY Honors/Model Boats/Answer Key"
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===j. Cavitation === | ===j. Cavitation === | ||
| + | Inefficient low-pressure pockets on propellers form bubbles that collapse against the blades resulting in premature wear. | ||
| + | . Cavitation causes vibration, noise and serious damage to your propeller. | ||
| + | |||
===k. Heeling === | ===k. Heeling === | ||
===l. Planing=== | ===l. Planing=== | ||
Revision as of 18:59, 16 September 2011
1. Do two of the following:
a. Purchase and build one kit for a sailboat 10 to 15 inches (25.4 to 38.1 cm) long and about four to five inches wide and operate boat on the water for at least two minutes.
b. Build a model boat with an electric motor from your own plans or from a kit, size 10 to 18 inches, (25.4 to 45.7 cm) and operate the boat for three to five minutes.
c. Build a model boat 18 to 30 inches (45.7 to 76.2 cm) long from your own plans or from a kit. Install a small bore internal combustion engine .029 or .049 and operate for at least two successful runs of three to five minutes each. Record in writing the operating characteristics of the model and state what you did to improve its performance.
2. Identify and define these words:
a. Displacement
Displacement is the volume of water a boat's hull moves out of the way when it floats. The displaced water is the same weight as the boat as long as the boat is floating. If the boat sinks then the amount of water being displaced is equal to the volume of the boat instead of the weight.
b. Center of gravity
c. Propeller pitch
"the distance a propeller would move in one revolution if it were moving through a soft solid, like a screw through wood." For example, a 21-pitch propeller would move forward 21 inches in one revolution.
d. Thrust and lift
e. Mono hull
the body of the boat
f. Hydro
g. Bow
the front of the boat
h. Keel
i. Transom
the wide, usually flat area at the very back of a boat. This is where an outboard motor is typically mounted. This is also where you usually find the name of the boat on larger vessels.
j. Cavitation
Inefficient low-pressure pockets on propellers form bubbles that collapse against the blades resulting in premature wear. . Cavitation causes vibration, noise and serious damage to your propeller.
