Glossary
-
TermDefinition
- General Nautical Terminology Helmsman
The individual responsible for steering and navigating a vessel, ensuring it maintains its intended course.
A helmsman plays a crucial role in...
More Details - Courses, RYA Helmsman's PracticalThe RYA Helmsman’s Practical course is designed to build confidence and competence in handling motorboats. Participants learn essential skills... More Details
- General Nautical Terminology, Signals & Communication HF
The radio frequency range between 3 and 30 megahertz (MHz), commonly used for long-range marine communications via skywave propagation.
High...
More Details - General Nautical Terminology, Navigation Highest Astronomical Tide (HAT)
The highest level of sea water that can be predicted to occur under average meteorological conditions and under any combination of astronomical...
More Details - General Nautical Terminology, Signals & Communication High Frequency (HF)
The radio frequency range between 3 and 30 megahertz (MHz), commonly used for long-range marine communications via skywave propagation.
High...
More Details - Organisation His Majesty's Nautical Almanac Office (HMNAO)
The UK government agency responsible for producing astronomical and navigational data for maritime and military use.
His Majesty's Nautical...
More Details - General Nautical Terminology, Knot Hitch
A knot that attaches a rope to an object, such as a post, ring, or other rope.
A hitch is a versatile and essential knot where securing a rope...
More Details - Flag Semaphore, Signals & Communication Letter H (Flag Semaphore)

This shape represents the Letter H (Flag Semaphore) and the Number 8 (Flag Semaphore).
- Morse Code, Signals & Communication Letter H (Morse Code)
International Morse Code sequence representing the letter H.
- Organisation HMCG
The organisation responsible for search and rescue operations in UK waters.
His Majesty's Coastguard (HMCG) is a section of...
More Details - Organisation HMNAO
The UK government agency responsible for producing astronomical and navigational data for maritime and military use.
His Majesty's Nautical...
More Details - General Nautical Terminology Hoist
To raise an object vertically, commonly a sail or flag, using a halyard.
It typically uses a system of ropes, cables, pulleys, and sometimes a...
More Details - General Nautical Terminology Holding Tank
A sealed onboard container designed to temporarily store wastewater, such as sewage or greywater, until it can be properly discharged at a...
More Details - General Nautical Terminology, Navigation Horizontal Dilution of Precision (HDOP)
Used in satellite navigation and positioning systems to quantify the accuracy of horizontal position measurements. It is a unitless factor that...
More Details - General Nautical Terminology, Safety Horseshoe Lifebuoy
A U-shaped flotation device designed to be thrown to a person overboard to provide buoyancy and aid in rescue.
The horseshoe lifebuoy, also...
More Details - Phonetic Alphabet, Signals & Communication Hotel
Pronounced: hoh-TELL
The term for the letter H in the NATO Phonetic Alphabet.
- General Nautical Terminology HoundsAttachments of stays to masts.
- General Nautical Terminology House flagAny personal flag or club flag flown from starboard spreaders or flagstaff.
- General Nautical Terminology Hull
The watertight body or shell of a boat or ship, excluding the deck, rigging, and other superstructures.
The hull is the fundamental structure...
More Details - General Nautical Terminology Hull SpeedThe maximum efficient speed of a displacement-hulled vessel.

