NAUTICAL TERMINOLOGY · NAUTICAL TERMINOLOGY It’s important to have a basic understanding of...

NAUTICAL TERMINOLOGY

It’s important to have a basic understanding of common nautical terms associated with the parts, positions and directions of your vessel. Knowing these terms will make it easier to communicate with people aboard the vessel. Having a working knowledge will also prove useful especially when communicating with passengers, crew, emergency or maritime authorities. The following illustration names the main exterior parts of a vessel. Transom refers to the wide, usually flat area at the very back of a boat, where an outboard motor is typically mounted. Gunwale (pronounced gunnel) the upper edge of a vessel’s side. Length overall refers to the distance between the hulls forward most and aft most extremes, excluding bolted on extensions. In the bow this would include a moulded anchor platform, but not a bowsprit.In the stern it would include a moulded swim step, but not stern drive propeller. Waterline length indicates the vessel’s length at the water surface. The keel is designed to control a vessel’s stability in water, helping it to move through the water rather than side-to-side. The bilge is an area where water and oil collects and may need cleaning and pumping out. Checking the bilge is a key pre-departure check which should be com-pleted prior to every trip out on the water.

Main exterior parts of a vessel

1 Nautical Terminology © 2019 National Maritime College

Directions and positions on a boat

The terms forward and aft are used to indicate locations and directions on the boat. Ahead and Astern indicate locations or directions beyond the vessel. Sideways directions are considered Abeam with the left side ofthe vessel called Port and the right side Starboard. Beam refers to the width at the vessel’s widest part. Port and Starboard Quarters refer to the hull area between the beam to the stern.

Freeboard Freeboard, an important factor in vessel stability. Freeboard refers to the distance from the waterline to do the lowest point of a vessel’s deck. It’s an important measurement as it determines how much weight a vessel can carry or, how it will perform in wind and waves. Waterline is the line (on the hull) at which the vessel sits in the water when it’s properly loaded with passengers and equipment. Draft is the depth of water that your vessel needs in order to float freely. The draft is measured as the distance from the waterline to the lowest point of the boat.


Nautical Terminology 2© 2019 National Maritime College


Wash and Wake Refers to waves which are created by a vessel as it travels through the water at varying speeds, draft and loads. The impact of this wash and wake varies depending on the type of vessel and the conditions. It can cause injury to people, the environment or infrastructure as you pass by. Always be mindful of you’re your wash and wake.

Wash and Wake at 4 knots

Engine at idle, no wash or wake. The vessel is flat in the water.




Engine just above idle. Small wash no wake. Vessel still flat in the water. 6 knots is the fastest you can travel without creating a wake. When operating a power-driven vessel at 6 knots or more the safe distance off rules apply.


As power increases the stern is forced lower in the water creating a rolling wake accross the back of the vessel and the bow rises up. This wake is the primary cause of damage to marine structures and shores causing bank erosion. In addition wake poses an additional threat of injury to people on anchored/moored vessels and near boat ramp areas, jettys, wharves and marinas.




The vessel is now accelerating and has started to plane or rise up and skim on top of the water instead of ploughing through it. Minimal wash and wake is created.

Safe Distance Requirements

Safe distance requirements refer to the minimum safe distance to keep from other vessels, people, or structures in the water when travelling at a speed of 6 knots or more.



When travelling at speeds of 6 knots or more a vessel must keep certain distance away from others as follows:

• 30 metres from moored or anchored vessels, shoreline, structures, including; jetty’s, bridges and navigation marks. Or, if that is not possible a safe distance. 30 metres is equivalent six, 5 metre boat lengths.

• 60 metres from a person in the water. This includes kayaks, row boats and sailing dinghies.

• 100 metres from a dredge, marina, work barge or vehicle ferry if you are travelling faster than 4 knots

• 200 metres distance from a power cable when anchoring. • 200 metres If towing aerial equipment (e.g. paraflying) from any bridge, cable, wire,

pipeline or structure.• 500 metres out from shore between surf patrol flags or signs. A designated swimming

area in a surf zone is defined as the area extending 500 metres out from shore between surf patrol flags or signs.

• Maintain a safe distance from any vessel towing a person.

Swimming and Surf Zones

Designated surf zones are areas extending 500 metres out from shore between surf patrol flags or signs. A designated swimming area in a surf zone is defined as the area extending 500 metres out from shore between surf patrol flags or signs. In all other areas a swimming area is defined as the area extending 60 metres out from shore between signs for swimmers. A person must not operate a vessel within 60 metres of a swimming area and the flags or signs marking these zones unless it is a vessel operated by Surf Life Saving Council lifeguards or unless permitted to so by a sign. These rules apply to all vessels including PWC.

All vessels must stay out side designated swimming areas and power-driven vessels smust not come within 60 metres unless permitted by signage. NSWRMS reproduced for educational purposes.


Upstream and Downstream Describe a vessel’s direction of travel. A vessel is said to be travelling upstream (coming in from sea) when it is coming in from sea in a direction towards land. A vessel is said to be travelling downstream (going out to sea) when it is heading away from land in a direction towards open water, out to sea.

Rhyme to help you remember which side you should pass a channel marker when travelling upstream or downstream. “Green to green when travelling upstream. Green to red when seas ahead.”




Steering Rules

Boat 1 (US) observes Boat 2 dead ahead on a collision course. Both Skipper’s must alter course to starboard (right) to pass well clear of each other passing port (left) to port. Boat 1 (US) observes Boat 3 approaching from the starboard (right) on a collision course. Boat 1 must give way to Boat 3 by slowing, stopping or altering course to starboard to GIVEWAY. Boat 1 (US) observes a Boat 4 approaching on a collision course from the port.(left) We have the right of way and maintain our course and speed. If boat 4 does not attempt to alter or change course course to give way to Boat 1 (US). Boat 1 must take evasive action to avoid a collision by first sounding 5 short blasts.Stop, alter course to starboard. DO NOT ALTER COURSE TO PORT and make every attempt to avoid a collision. Boat 1 (US) observes Boat 5 (yacht) MUST giveway, alter course to starboard and pass astern (behind) the yacht. Boat 6 is overtaking and must keep clear of Boat 1 (US) passing either side. Boat 1 (US) maintains course and speed.


Tide Terminology

Chart Datum The level below which all depths are published on a navigational chart. It is also the level to which tidal heights are referred to. By adding the tidal height to the charted depth, the true depth of water is determined. By international agreement, Chart Datum is defined as the lowest predictable level that the tide is likely to fall.

Tidal Range The difference in height of water between high and low tides.

MLWS and MHWS The height of mean high water springs is the average of the heights of two successive high waters during those periods of 24 hrs (approximately once a fortnight) when the range of the tide is greatest. The height of mean low water springs is the average height obtained by the two successive low waters during the same period. MHWS - The average height of the high waters of spring tides above Chart Datum. MLWS - The average height of low waters of spring above Chart Datum.

Draft The depth of a vessel below the waterline at the deepest point of its keel. The minimum depth of water a vessel needs to float in.

UKC Under Keel Clearance, or UKC is the vertical distance between the lowest part of the vessel’s hull and the seabed.



Knowing tide information for your planned boating area and the under keel clearance of your vessel will help you steer clear of rocks, sandbars and other underwater hang-ups which could bring your happy day of boating to a grinding halt.



NAUTICAL TERMINOLOGY · NAUTICAL TERMINOLOGY It’s important to have a basic understanding of...

Documents

Transcript of NAUTICAL TERMINOLOGY · NAUTICAL TERMINOLOGY It’s important to have a basic understanding of...