International Convention on Load Lines
It was adopted in 1966 and entered into force in 1968.
It has long been recognized that limitations on the draught to which a ship may be loaded make a significant contribution to her safety. The main objective of the Convention is to set these limits in the form of freeboards, besides external weathertight and watertight integrity.
In the 1966 Load Lines convention, adopted by IMO, provisions are made for determining the freeboard of ships by ‘subdivision’ and ‘damage stability calculations’.
The regulations take into account the potential hazards present in different zones and different seasons. Thus, the Convention sets the minimum permissible freeboards, according to the location of the ship and season of the year.
The technical annex contains several additional safety measures concerning doors, freeing ports, hatchways and other items. The main purpose of these measures is to ensure the watertight integrity of ship’s hulls below the freeboard deck.
All assigned load lines must be marked amidships on each side of the ship, together with the deck line. Ships intended for the carriage of timber deck cargo are assigned a smaller freeboard as the deck cargo provides protection against the impact of waves.
PURPOSE OF THE CONVENTION:
To ensure seaworthiness of the Intact (undamaged) vessel by:
- Ensuring that the vessel has adequate reserve buoyancy and is not overloaded. This is done by limiting the maximum loaded draft.
- Ensuring a strong hull that can withstand severe sea conditions. This is done by proper structural design, construction and maintenance.
- Ensuring weathertight and watertight integrity. By ensuring good conditions of coamings, doors, hatches, hatchways, non-return valves, etc.
- Ensuring vessel has adequate stability for all loading and operating conditions.
- Ensuring rapid drainage of water on deck during shipping seas. This is done by adequate arrangements of freeing ports in bulwarks, scuppers, etc.
- Ensuring safety of crew while on deck by increased freeboard to reduce boarding seas, guard rails, catwalks, etc.
- Ensuring that modifications to vessels do not compromise seaworthiness. Any modification must be approved by the load line assigning authority.
CONTENTS:
The Convention comprises of 34 articles and 3 annexes.
- Annex I is divided into four Chapters:
Chapter I – General;
Chapter II – Conditions of assignment of freeboard;
Chapter III – Freeboards;
Chapter IV – Special requirements for ships assigned timber freeboards. - Annex II covers Zones, areas and seasonal periods.
- Annex III contains certificates, including the International Load Line Certificate.
APPLICATION:
The present convention applies to all ships engaged on international voyages, except war ships, new ships of less than 24m in length, existing ships of less than 150 GT, fishing vessels, pleasure crafts, etc.
REQUIREMENTS:
All the ships, to which the Convention applies, need to be surveyed and assigned an International Load Line Certificate without which it cannot trade. Certain ships, based on their design or trade pattern, do not require such a certificate. These types of ships are described under Article 6 of the Convention and are given a ‘Load Line Exemption Certificate’.
Under this Convention, each ship is issued a “Condition of Assignment” by the certificate issuing authority, which gives the details of the structure and equipment to be surveyed and maintained.
AMENDMENTS
After the Convention came into force, various amendments were adopted in the following years, but they required positive acceptance by two-thirds of Parties and never came into force.
However, the 1988 Protocol, entered into force in 2000. It made provisions for harmonizing the Convention’s survey and certification requirement with those contained in the SOLAS and MARPOL conventions. It also revised certain regulations in the technical Annexes and introduced the ‘tacit
acceptance procedure’, so that amendments adopted will enter into force six months after the ‘deemed date of acceptance’ unless they are rejected by one-third of Parties. Usually, the deemed acceptance date is two years from the date of adoption.
The 2003 Amendments which entered into force in 2005, made comprehensive changes to technical regulations of the original convention.
SALIENT FEATURES OF THE LOAD LINE CONVENTION
- All ships for trading need to be surveyed and need to carry the certificates as per Load Line Rules. They must be exhibited in a prominent part of the ship and be presented to the customs for Port Clearance.
- Ships must be marked with load line in accordance with the Rules.
- Ships must comply with the Condition of Assignment as per the Rules.
- Ships must be provided with information regarding stability, loading and ballasting and additional notes for Master’s guidance.
- Load Line Rules apply at port as well as at sea, except when a ship is proceeding down river to the sea, she may submerge her marks to allow for the river passage consumption of fuel and FW, and rise (increase in freeboard) due to increase in density of water when she leaves dock water.
INITIAL, RENEWAL AND ANNUAL SURVEYS
A ship shall be subjected to the surveys specified below:
- An initial survey before the ship is put in service, which shall include a complete inspection of its structure and equipment, as covered by the present Convention. The survey shall be such as to ensure that the arrangements, materials and scantlings fully comply with the requirements
of the present Convention. - A renewal survey at intervals specified by the Administration but not exceeding five years, which shall be such as to ensure that the structure, equipment, arrangements, materials and scantlings fully comply with the requirements of the present Convention.
- An annual survey within 3 months before or after each anniversary date of the certificate to ensure that,
- alterations have not been made to the hull or superstructures which would affect the calculations determining the position of the load line
- the fittings and appliances for the protection of openings, guard rails, freeing ports and means of access to crew’s quarters are maintained in an effective condition
- the freeboard marks are correctly and permanently indicated
- the required information is supplied to the Master The annual surveys shall be endorsed on the International Load Line Certificate or International Load Line Exemption Certificate, as applicable.
LOADLINE CERTIFICATE 1966
Ships to which the Convention applies have a Load Line certificate or a Load Line Exemption certificate.
- Validity of the certificate is 5 years, subject to Annual inspection.
- The surveying and marking of the ship shall be carried out by Administration. However, this task can be entrusted to organizations recognized by it. In every case the Administration concerned fully guarantees the completeness and efficiency of the surveys and marking.
- An International Load Line Certificate shall cease to be valid if any of the following circumstances exist:
- Material alterations have taken place in the hull or superstructures that would necessitate the assignment of an increased freeboard
- the required fittings and appliances are not maintained in an effective condition
- the certificate is not endorsed after the Annual or Periodic Survey.
- the structural strength of the ship is lowered to such an extent that the ship is unsafe.
Information to be Supplied to the Master
The master of every new ship shall be supplied with information to arrange for the loading and ballasting of his ship in such a way as to avoid the creation of any unacceptable stresses in the ship’s structure.
Information shall be provided to the master in a form that is approved by the Administration or a recognized organization.
Stability information and loading information shall be carried on board at all times together with evidence that the information has been approved by the Administration.
A ship which is not required under SOLAS to undergo an inclining test upon its completion shall
- be so inclined and the actual displacement and position of the centre of gravity shall be determined for the lightship condition
- if the Administration so approves, have the inclining test data obtained from that of a sister ship.
- if the Administration decides that the performance of an inclining experiment is not practicable or safe, the ship’s lightship characteristics can be determined by a detailed weight estimate confirmed by a lightweight survey
Where any alterations are made to a ship so as to materially affect the loading or stability information supplied to the master, amended information shall be provided. If necessary the ship shall be re-inclined.
LOAD LINE MARKINGS:
Deck Line – The deck line is a horizontal line 300 mm in length and 25 mm in breadth. It shall be marked amidships on each side of the ship, and its upper edge shall be in line with the freeboard deck.
Load Line Mark – The load line mark shall consist of a ring 300 mm in outside diameter and 25 mm wide which is intersected by a horizontal line 450 mm in length and 25 mm in breadth, the upper edge of which passes through the centre of the ring. The centre of the ring shall be placed amidships and at a distance equal to the assigned summer freeboard measured vertically below the upper edge of the deck line.
Lines to be used with the Load Line Mark – The lines which indicate the load line assigned in accordance with the Load Line regulations shall be horizontal lines 230 mm in length and 25 mm in breadth which extend forward of, unless expressly provided otherwise, and at right angles to, a vertical line 25 mm in breadth marked at a distance 540 mm forward of the centre of the ring. The following load lines
shall be used:
- The Summer Load Line indicated by the upper edge of the line which passes through the centre of the ring and also by a line marked S.
- The Winter Load Line indicated by the upper edge of a line marked W.
- The Winter North Atlantic Load Line indicated by the upper edge of a line marked WNA.
- The Tropical Load Line indicated by the upper edge of a line marked T.
- The Fresh Water Load Line in summer indicated by the upper edge of a line marked F and marked abaft the vertical line.
- The Tropical Fresh Water Load Line indicated by the upper edge of a line marked TF and marked abaft the vertical line.
Timber Load Lines – If timber freeboards are assigned, the timber load lines shall be marked in addition to ordinary load lines. These lines shall be horizontal lines 230 mm in length and 25 mm in breadth which extend abaft, unless expressly provided otherwise, and at right angles to, a vertical line 25 mm in breadth marked at a distance 540 mm abaft the centre of the ring. Timber load lines are Summer Timber Load Line (LS), Winter Timber Load Line (LW), Winter North Atlantic Timber Load Line (LWNA), Tropical Timber Load Line (LT), Fresh Water Timber Load Line in summer (LF – marked forward of the vertical line) and Tropical Fresh Water Timber Load Line (LTF – marked forward of the vertical line)
The Mark of the Authority – The mark of the Authority by whom the load lines are assigned may be indicated alongside the load line ring above the horizontal line which passes through the centre of the ring, or above and below it. This mark shall consist of not more than four initials to identify the Authority’s name, each measuring approximately 115 mm in height and 75 mm in width.
Marking – The ring, lines and letters shall be painted in white or yellow on a dark ground or in black on a light ground. They shall also be permanently marked on both sides of the ship to the satisfaction of the Administration. The International Load Line Certificate shall not be delivered to the ship until the surveyor has certified that the marks are correctly & permanently indicated on the ship’s sides.
LOAD LINE SURVEY:
The following items will be checked during the Annual Load Line survey:
- A visual examination of the Load Line certificate and all other certificates to ensure validity and all endorsements are carried out.
- A general inspection to ensure that no unauthorized modifications are carried out which affect the ‘Condition of Assignment’ of load lines for the vessel.
- Inspection of the strength in general by internal inspection of one or two compartments and gauging the strength of the girders, frames, knees, brackets, etc. Also, strength of the superstructure bulkheads and machinery spaces will be checked.
- Confirming that loading and ballasting operations are carried out without excessive stresses and vessel makes good use of the stability information booklet and loading computer.
- The position and marking of the load lines on the P & S sides of the ship to be checked as per the load line certificate. Also, draft marks will be checked.
- Hatch covers must be weathertight. All fittings such as rubber packing and closing appliances must be in good condition. Testing may be carried out for few holds.
- Ventilators will be tested to see if they can be closed effectively. The rubber packings and open-shut markings will also be checked.
- Watertight doors and their operation, packing, markings, alarms, controls, etc. will be checked.
- Weathertight doors packing, closing mechanism such as dog bolts, markings, etc. will be inspected.
- Air pipe flaps will be inspected to check if they are capable of being shut. Valves must be operational and packing must be in good condition. Air pipes with floating discs or ball mechanism will be checked.
- Machinery space openings must be capable of being shut as per local or remote operation where fitted.
- Portholes are to be weathertight and those below the main deck must be watertight and fitted with deadlights.
- All inlet and outlet valves must be watertight and show no leakage. The forepeak tank valve which is of the screw-down type must be capable of being closed watertight.
- All manholes and their rubber packing will be checked for condition and weathertightness.
- Freeing ports and scuppers must not be blocked or obstructed.
- Life-life on deck for rough weather, catwalk, guard rails, bulwarks, etc. must be in good condition and adequate for its purpose.
- Forepeak educator system for chain locker must be operational, including its alarm system. Spurling pipe opening must be capable of being closed weathertight.
CONTENTS OF AN INTERNATIONAL LOAD LINE CERTIFICATE:
- Certificate Number
- Issuing Authority (under the Authority of __)
- Issued By (Classification Society)
- Name of the ship, Call Sign, Port of Registry, IMO number, etc
- Type of Ship (A or B60 or B100)
- Freeboard assigned as (New ship)
- Length of the ship (as defined in the Convention)
- Freeboards from Deck Line for all the Load Line Marks in ‘mm’
- Fresh Water Allowance in ‘mm’
- Valid until date, subject to Annual surveys.
- Completion date of the survey, date and place of issue of the Certificate
- Sign and seal of the Authorized Person.
- Space for Annual endorsements and other remarks.
RECORD OF CONDITION OF ASSIGNMENT
Conditions of Assignment are the conditions which must be met before freeboard is assigned to a ship and load line certificate is issued following a load line survey.
Free boards are computed assuming ship to be a completely enclosed and watertight/ weather tight envelop. The convention then recognizes the practical need for openings in the ship and prescribes means of protection and closure of such openings. These are called condition of assignment, since the assignment of computed free board is conditional upon the prescribed means of protection and closure of openings such as hatchways, doorways, ventilation, air pipes, scuppers etc.
Following are the conditions which must be met before assigning the freeboard:-
- Enough structural strength should be possessed and preserved.
- Enough reserve buoyancy should be possessed and preserved.
- Physical means of preventing entry of water into the hull.
- Safety and protection of crew on weather deck.
- Adequate stability in the normal loaded condition (intact stability)
- Adequate degree of subdivision and stability after suffering prescribed damage.
Ships are to be surveyed annually to ensure that they fulfill the condition of assignment. Most of the conditions of assignment are concerned with the water tight integrity of the ship.
Hull construction should meet the highest standard laid down by the classification society. This ensures protection against flooding of the ship. The superstructure and the bulkheads must be strengthened sufficiently.
Some of the condition of assignment which contribute towards water tight integrity and compliance with other objectives of the convention are:-
1) Hatchways
2) Machinery space openings
3) Watertight doors
4) Weather tight doors (Openings in free board and super structure deck)
5) Ventilators, Cargo ports, Air pipes
6) Scuppers
7) Side scuttles, Port holes and deadlights
8) Inlets and discharges and non-return valves
9) Guard Rails, Cat-walk, bulwarks and freeing ports
10) Load line Marks and draft marks
Good condition of most of the above parameters ensures watertight integrity and protection against flooding of compartment. If watertightness is not achieved, then during rough weather water can enter into the areas below main deck causing to reduce the free board. Also if green sea effect is not reduced and water is being accumulated on the deck, it can cause free board to reduce and add free surface effect.
Condition of assignment needs periodic inspection to ensure that ship conditions are such that above mentioned items are maintained in good order. During periodic inspection, surveyor shall assume that no material alterations have been made to the hull or superstructure that would affect the calculation determining the position of load line. This can be found out by reviewing the records of condition of assignment.
Examples of items which may no longer fulfill the conditions could be:
- Corrosion or damage to hatch coaming, ventilators, air pipes, etc.
- Damaged gangways, guard rails, bulwarks, catwalk, etc. that will hamper the safety of crew.
- Sealing arrangements of closing devices are made of neoprene. They become hard with time and needs renewal.