Navigation & Route Planning Flashcards

What is the primary purpose of a Float Plan before departure?

Answer: To inform someone onshore of your route, destination, and expected return time

A float plan left with a responsible person onshore helps rescuers know where to look if you don't return as expected.

A white buoy with an orange circle and black lettering is a:

Answer: Regulatory marker indicating a speed limit, danger, or restricted area

Orange circle on white regulatory markers indicates a controlled or restricted area such as a no-wake or no-entry zone.

When planning a trip through tidal waters, why is knowing the current tide stage important?

Answer: To ensure adequate water depth exists when crossing shallow bars or inlets

Tide height directly affects water depth, so crossing shoals, bars, or inlets should be timed around high tide for adequate clearance.

What is the correct way to read a chart's compass rose?

Answer: The outer ring shows true north; the inner ring shows magnetic north

On nautical chart compass roses, the outer ring is oriented to true north and the inner ring to magnetic north.

A vessel is navigating upstream on a river. According to the US ATON system, the red buoys should be:

Answer: On the vessel's starboard (right) side

On rivers, 'returning from sea' is defined as going upstream, so red buoys remain on the starboard side going upriver.

What does it mean when a chart shows a 'drying height' for a feature like a rock?

Answer: The feature is above water at low tide and below water at high tide

A drying height indicates the feature is exposed above water at low tide but covered at high tide, making it a significant hazard.

When using GPS for navigation, what is 'HDOP' and why does it matter?

Answer: Horizontal Dilution of Precision — a measure of GPS accuracy based on satellite geometry

HDOP measures GPS accuracy; a lower HDOP value means satellites are well-spaced and position accuracy is better.