Load Line Markings
The first official loading regulations are thought to date back to maritime legislation originating with the Kingdom of Crete in 2500 BC when vessels were required to pass loading and maintenance inspections. Roman sea regulations also contained similar regulations.
In the Middle Ages the Venetian Republic, the city of Genoa and the Hanseatic League required ships to show a load line. In the case of Venice this was a cross marked on the side of the ship and of Genoa three horizontal lines.
However over the centuries, greed took over and malpractises of overloading started around the world.
Coffin ships
Coffin ship is the name given to any ship that has been over-insured and is therefore worth more to its owners sunk than afloat. These were hazardous places to work in the days before effective maritime safety regulation. They were generally eliminated in the 1870s with the success of reforms championed by British MP Samuel Plimsoll.
Lord Plimsoll
Many of these in the days of wooden sailing ships were old ships riddled with wood rot, woodworm and shipworm, repainted, renamed and falsely stated to be new ships. There were over 2000 cases of sailors who had signed on as crew for a ship, saw the ship’s condition and refused to go on board it. They were tried in court for this refusal. Samuel Plimsoll took up this issue.
Samuel Plimsoll (10 February 1824 – 3 June 1898) was an English politician and social reformer, now best remembered for having devised the Plimsoll line (a line on a ship’s hull indicating the maximum safe draft, and therefore the minimum freeboard for the vessel in various operating conditions).
In 1867, Plimsoll was elected as the Liberal Member of Parliament for Derby, and endeavored in vain to pass a bill dealing with the subject of a safe load line on ships. The main problem was the number of ship-owning MP’s in Parliament.
In 1872, he published a work entitled Our Seamen, which became well known throughout the country. Accordingly, on Plimsoll’s motion in 1873, a Royal Commission was appointed and in 1875 a government bill was introduced, which Plimsoll, though regarding it as inadequate, resolved to accept. Attempts were made by the Prime Minister to drop the bill. However popular feeling forced the government to pass a bill which in the following year was amended into the Merchant Shipping Act.
This gave stringent powers of inspection to the Board of Trade and the mark that indicates the safe limit to which a ship may be loaded became generally known as Plimsoll’s mark or line.
The waterline is the line where the hull of a ship meets the surface of the water, in concept or reality. Specifically, it is also the name of a special marking, also known as an international load line, Plimsoll line and water line (positioned amidships), that indicates the draft of the ship and the legal limit to which a ship may be loaded for specific water types in order to safely maintain buoyancy, particularly with regard to the hazard of waves that may arise.
The purpose of a load line is to ensure that a ship has sufficient freeboard (the height from the water line to the main deck) and thus sufficient reserve buoyancy. The freeboard of commercial vessels is measured between the lowest point of the uppermost continuous deck at side and the waterline and this must not be less than the freeboard marked on the load line certificate issued to that ship. All commercial ships, other than in exceptional circumstances, have a load line symbol painted amidships on each side of the ship. This symbol is also permanently marked, so that if the paint wears off it remains visible. The load line makes it easy for anyone to determine if a ship has been overloaded. The exact location of the load line is calculated and verified by a classification society and that society issues the relevant certificates.
Load Line
As we have already defined above, Load Line is a special marking positioned amidships. All vessels of 24 meters and more are required to have this Load line marking at the centre position of the length of summer load water line.
There are two types of Load line markings:-
Standard Load Line markings – This is applicable to all types of vessels.
Timber Load Line Markings – This is applicable to vessels carrying timber cargo according to regulations.
These marks embossed on the surface of the hull making it visible even if the ship side paint fades out. The marks shall again be painted with white or yellow colour on a dark background / black on a light background.
The complete Load line markings consist of 3 vital parts.
Deck Line – It is a horizontal line measuring 300mm by 25mm. It passes through the upper surface of the freeboard.
Load Line Disc – It is 300mm diameter and 25mm thick round shaped disc. It is intersected by a horizontal line. The upper edge of the horizontal line marks the ‘Summer salt water line’ also known as ‘Plimsoll Line’.
Load Lines – Load lines are horizontal lines extending forward and aft from a vertical line placed at a distance of 540mm from the centre of the disc. They measure 230mm by 25mm. The upper surfaces of the load lines indicate the maximum depths to which the ships maybe submerged in different seasons and circumstances. On most ships, you find paint colour changing at Summer mark.
This is how it is seen on the Starboard side of shipside.
S – Summer :- It is the basic freeboard line at the same level as the Plimsoll Line. Other load lines are marked based on this Summer freeboard line.
T – Tropical :- It is 1/48th of summer draft marked above the Summer load line.
W – Winter :- It is 1/48th of summer draft marked below the Summer load line.
WNA – Winter North Atlantic :- It is marked 50mm below the Winter load line. It applies to voyages in North Atlantic ( above 36 degrees of latitude) during winter months. Ship’s length not exceeding 100 m.
F – Fresh Water :- It is the summer fresh water load line. The distance between S and F is the Fresh Water Allowance (FWA)mm = Displ / (4 x TPC).
TF – Tropical Fresh Water :- It is the fresh water load line in Tropical. It is marked above the T at an amount equal to FWA
Add Load line zones explanation and chart
Load Line Zones
They are Seasonal.
The seasonal zones, areas and periods that determine the appropriate load line in a particular sea area at a given time of the year are by way of the chart
The Tropical, Summer and Winter freeboard zones are based upon the following weather criteria:
Summer zones: Regions where not more than 10% of wind speeds exceed force 8 Beaufort (34 Knots)
Tropical Zones: Regions where not more than 1% of wind speeds exceed force 8 Beaufort (34 knots) and not more than one tropical storm in a ten-year period occurs in an area of 50 Latitude/Longitude square in any one separate calendar month.
Winter Zones – Are all other regions
Draft Marks
What are draft marks? Why do you need them?
All the ships have draft marks in the forward, aft and midship region on port and Starboard sides. These marks are used to verify the draft of the ship in any loading condition. In simpler words draft mark tells us what is the ships depth at that time. It is distance from the Waterline to the lowest part of the ship.
Draft readings when used for calculations give us underwater volume and Displacement. This helps in knowing cargo quantity on board.
Draft also tells us about minimum depth requirements for ship to stay afloat.
How do you read Load lines and Draft marks?
LOAD LINES: They are marked only Amidships on both sides. Upper edge of the load line indicates correct reading. We do not measure anything on Load Line markings. We just have reading of Yes/No. Load lines deal with FREEBOARD only and NOT DRAFT.
DRAFT MARKS: They are marked on both sides, Forward, Mid-ship and Aft. Readings are taken on both sides and averaged.
When the markings are in meters, the main meter marks are marked as numbers followed by the letter M such as 8M, 9M, 10M. In between the metric marks are numeral markings such as 2, 4, 6 and 8 to indicate 20 cm, 40cm, 60 cm and 80 cm. The height of each mark is 10 cm and the distance between the mark in 10 cm.
If the water is just in line with the LOWER EDGE of the mark 10M, the draft is 10.0 meters. If the water is in line with the top edge of 10 M, then the draft is 10.10 meters and so on.
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