RYA Day Skipper Navigation and Chartwork 2

Question 1

What is an 'estimated position' (EP) in navigation?

Accepted Answer

A position derived from the last known position, course steered, and distance run, with an allowance for tidal stream and leeway

Answer

An EP is a best estimate of position calculated by applying the course steered, log distance, estimated tidal stream, and leeway to the last known position. It is marked with a triangle on the chart.

Question 2

What does a 'leading line' or 'transit' provide for a navigator?

Accepted Answer

A line of position confirmed by aligning two charted objects, providing a reliable bearing

Answer

A transit (or leading line) is formed when two charted objects are in line. This provides a very accurate line of position and is often used for entering harbours safely.

Question 3

On an Admiralty chart, what does a magenta diamond symbol indicate?

Accepted Answer

A reference to additional information in the chart notes or tidal diamond data

Answer

Magenta diamonds on Admiralty charts refer to tidal stream information. Each diamond has a letter that corresponds to a tidal stream table on the chart, showing direction and rate.

Question 4

What is the purpose of a 'course to steer' calculation?

Accepted Answer

To find the compass heading that will result in the vessel making good the desired track over the ground, allowing for tide and leeway

Answer

A course to steer calculation determines the compass heading to counteract the effects of tidal stream and leeway, ensuring the vessel follows the intended ground track.

Question 5

What does the abbreviation 'Fl(3) 15s' on a chart mean for a light?

Accepted Answer

A light showing a group of 3 flashes with a total period of 15 seconds

Answer

Fl(3) 15s describes a group flashing light that shows 3 flashes in succession, with the complete cycle (including dark intervals) repeating every 15 seconds.

RYA Day Skipper Practice Test

RYA Day Skipper Practice Test

RYA Day Skipper Navigation and Chartwork 2