Glossary

A slender, upright floating marker used to make a position conspicuous on the water.

A dan buoy typically has a weighted or ballasted lower...

A lightweight stock anchor with two broad pivoting flukes designed to penetrate suitable sand or mud.

The stock holds the crown and flukes at...

A charted wreck whose depth or clearance may present a hazard to surface navigation.

It is identified by the appropriate dangerous-wreck...

A lifting appliance fitted to a vessel or structure for lowering and recovering a boat or other load.

Davits commonly handle lifeboats, rescue...

A prescribed geometric shape displayed by day to indicate a vessel's status, operation or restriction under the collision regulations.

Balls,...

An RYA practical motor-cruising course developing the ability to skipper short passages by day.

It covers preparation, pilotage, navigation,...

An RYA practical sail-cruising course developing the ability to skipper short passages by day.

It combines pilotage, navigation, safety, crew...

An RYA shorebased navigation course providing the theory needed to plan and conduct coastal passages at day-skipper level.

It covers charts,...

An International Code of Signals flag whose single-letter meaning is “Keep clear of me; I am manoeuvring with difficulty.”.

The Delta flag may...

Estimating a vessel’s position by advancing a known position using course steered, speed through the water and elapsed time.

A dead-reckoning...

The shipboard department responsible for navigation, cargo work, deck maintenance and many seamanship operations.

It is normally led by the...

A certificated member of a ship’s deck department who performs navigational watches and deck-management duties.

Depending on rank, a deck...

A mast whose heel is supported on the deck rather than continuing through it to a step below.

Compression loads are transferred through the...

Abbreviated DW.

It is a route within defined limits that has been accurately surveyed for clearance of the seabed and submerged obstacles.

The standard spoken code word for the letter D in the international radiotelephony spelling alphabet.

It is pronounced “DELL-tah” and is used...

A depositional landform built where a river delivers sediment into a sea, lake or other relatively still body of water.

As flow slows,...

A proprietary-style fixed-shank plough anchor with a weighted, roughly triangular fluke designed to set quickly.

The original Delta design and...

The detailed pilotage plan for leaving a berth, harbour or constrained waterway.

It covers unberthing, communications, tidal and weather...

An area of relatively low atmospheric pressure, usually associated with cyclonic circulation and unsettled weather.

In the Northern Hemisphere...

A line on a nautical chart joining points of equal charted depth relative to the chart’s vertical datum.

Also called an isobath, a depth...