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Comprehensive Guide to Marine Survey

Cargo-Ship-marine-surveyMarine surveyors perform inspections of vessels of all types including pleasure craft, passenger vessels, tugboats, barges, dredges, oil rigs, ferries, cargo vessels and warships, as well as marine cargo, marine engines and facilities such as canals, drydocks, loading docks and more for the purpose of pre-purchase evaluation, insurance eligibility, insurance claim resolution and regulation compliance.

Surveys typically include the structure, machinery and equipment (navigational, safety, radio). Marine surveyors also are involved in other aspects, including confirming compliance with international treaties associated with such things as pollution, international security, and safety management schemes. They may also examine cargo gear to ensure that it meets the requirements or regulations.

Marine surveyors may perform the following tasks:

  • examine and approve design plans of hulls and equipment such as main propulsion engines, auxiliary boilers and turbines, electrical power generating plant, refrigeration and air conditioning plant and pumping systems
  • inspect standards of construction and witness tests of materials
  • inspect hulls, machinery and equipment during ship construction to ensure standards and legislative requirements are met
  • conduct surveys throughout the ship’s life to ensure standards are maintained
  • perform inspections required by domestic statutes and international conventions
  • witness tests and operation of emergency and safety machinery and equipment
  • measure ships for tonnage and survey them for load line assignment
  • attend court as an expert witness and assist in coronial enquiries
  • investigate marine accidents.


Classification Society Marine Surveyor

A classification society marine surveyor inspects ships to make sure that ships, components and machinery are built according to the standards required for their class, and examines accident damage.

Government Marine Surveyor

A government marine surveyor inspects ships to make sure that ships, components and machinery meet crew and passenger safety regulations and construction standards. They may also assess and approve safety reports and plans as well as examine candidates for certificates of competency.

Private Marine Surveyor

A private marine surveyor examines ships and their cargoes, investigates accidents in port and at sea (e.g. oil spillages) and prepares accident reports for insurance purposes.

Well, sometimes the surveyor must enter confined spaces.
Work in confined and enclosed space has a greater likelihood of causing fatalities, severe injuries and illness than any other type of shipyard work or onboard ships.

The key hazards associated with confined spaces are:

  • Serious risk of fire or explosion;
  • Loss of consciousness from asphyxiation arising from gas, fumes, vapor or lack of oxygen;
  • Drowning arising from increased water level;
  • Loss of consciousness arising from an increase in body temperature;
  • Asphyxiation/suffocation arising from free flowing solid (engulfment) or the inability to reach a breathable atmosphere due to entrapment.

Likewise, the Surveyors will routinely enter confined spaces that are difficult to access due to small and/or narrow openings. There may be physical constraints within the space which need to be considered, and the space itself may be cramped permitting only restricted mobility.
Given the usual enclosed and darkened nature of a confined space this activity ideally should not be carried out by personnel suffering from phobias (e.g. claustrophobia) or who are susceptible to panic or anxiety attacks.
For further details regarding hazards in confined spaces see Annex, section 2, Confined Space Hazards.


  • Do not enter a space first or alone!
  • If in doubt – do not enter – no survey is worth risking life or health for.

Rol of Surveyor

Prior to the survey, he surveyor should review the ship’s file.  He must verify the class and statutory position.

He must be aware of the rules and procedures that are involved in order to satisfactorily complete the survey.  When he goes on board the ship, one of the first things he must do is to check the certificates.  The true class position is not what is shown in equaisis, but what is on board the ship, and therefore the certificates are the first thing that must be checked.  He should compare the position on board with the position he found in equasis.  If there are any inaccuracies, he must report them to the Main Office as soon as possible in order that the computer is up dated accordingly.

He must ensure that there are no overdue recommendations or surveys.  If there are, he must approach the owner’s representative, the captain or the superintendent, to see that they are performed.  He cannot leave the ship with overdue surveys or overdue recommendations.  This is very important.  He should explain the survey scope and schedule with the owners, i.e. the Captain, Chief Engineer Officer or the Superintendent.

A badly planned survey means a lot of wasted time and frustration.  Remember that the crew are not there just to cater to the needs of the surveyor.  The ship is in port to load or discharge a cargo.  The crew have their functions; they cannot suddenly drop everything to launch a lifeboat.  So it is very important that the surveyor plans the surveys with the owner’s representative.  He must explain what he is going to do, whether he needs any tanks to be opened up, whether he wants any tests performed.  And he must agree the schedule with the owners.  If this is done, it will speed up the survey and give a very good impression to the owners, and establish a good working relationship.  If not, everyone is frustrated and angry.
Surveyor Safety

General Precautions
The surveyor must be suitably dressed for the space to be inspected. This means that if he has to go into dangerous spaces, he must be suitably dressed, in a boiler suit, with the right shoes, gloves, and hard hat.

Remember, the boiler suit must be in good condition and reflect the quality of our Society.

When the surveyor is on a tanker, shoes should be such that they will not give off any sparks if struck against steel. The surveyor should carry a suitable torch, again depending on the space to be inspected this may have to be a gas proof torch. In an ordinary hold, where there are no problems with dangerous or flammable gases, it may not be necessary to use such a torch. But when going into compartments that might contain dangerous or flammable gases, a gas proof torch must be used.

When conducting machinery surveys, the surveyor must be aware in case any of the contents of his pockets fall into the machinery itself. The surveyor must never start any machinery or accept alarms, this is the responsibility of the crew.

The surveyor has to climb around the hold or the ship’s side, and if the scaffolding is in poor condition there is danger that he may fall, or knock a piece of steel over which could fall on to somebody’s head. If the timber of the scaffolding is in bad condition, too narrow or badly fixed, the surveyor should decline to perform the survey until the scaffolding is put right.

Hatch covers can also pose a problem, particularly wooden hatch covers with canvas stretched across them. One cannot see whether the hatch board is there. If you are walking or planning to walk on wooden hatch covers, make sure that all hatch boards are in position.

Similarly, when climbing or going down ladders, if the ladder rungs are missing or in very bad condition, they should be repaired, because they are dangerous and affect the safety of the surveyor. In icy conditions, ladders or platforms can be very slippery and very dangerous. This is particularly the case if you are going into an oil tanker or tanker, and the steel is coated with a veneer of oil, which can
be very slippery and very dangerous.

Quite often, if a ship is under repair, deck plates are removed and no protection or prevention is erected to stop anyone falling down a hole. Obviously when you are going around a ship you have to pay particular attention to this, especially where the ship is under major repairs in a shipyard. Similarly, the surveyor must be aware of the dangers of the temporary cables and pipe lines that are necessary for the repairs.If he is conducting a survey and people are working above him, he must be careful, because anything could fall, and if he is not wearing a hard hat or is not suitably protected, this can be very dangerous.

On a heavy‑lift ship when they are making a heavy lift, he should not be in holds or tanks or confined spaces.

In the event of an accident during the heavy lift, the ship could roll and this could seriously affect the safety of anyone inside confined spaces. Electrodes and welding give rise to very high‑intensity light. If you look at welding without protective eyeglasses, then you can damage your eyesight. In mild cases the damage is temporary, but extremely uncomfortable. In serious cases, there can be permanent eye damage. There is always welding on board, and he should be careful at all times.

Never conduct a survey alone, or when the shipyard has closed, or there are no workers around. If the surveyor becomes trapped in a compartment, or falls, and no one knows where he is, then he could remain there indefinitely, with serious consequences.

Carrying out internal inspections in poor lighting is also very dangerous. First, he cannot see to survey properly, but it is also dangerous walking around there could be a lighting hole not protected, and he could fall.

The same goes for the slippery surface of a tank, caused by oil or other products. A slip could prove fatal.
Open manholes, stringer plates, all may be dangerous if the surveyor is not looking where he is going, concentrating on the inspection he may forget where he is putting his feet. Handrails and ladders become corroded and weakened, be careful using them.

When a ship is in a shipyard, the shipyard invariably has its own safety regulations and requirements. These Regulations should be strictly observed. Similarly, on a ship, it may have its own safety regulations that must be carefully followed.

If the surveyor is in a tank, and experiences any slight dizziness or lack of balance, this is the initial warning of oxygen deprivation, and he should leave the compartment immediately. Do not hang around. He must exit into the fresh air, and ask for the compartment to be properly ventilated before he can resume his surveys.

The optimum oxygen level is between 20.8 and 21 per cent. When it goes below 20.8 per cent, there are dangers of asphyxiation. If there is 10 per cent combustible gases present in the atmosphere, that is enough for an explosion. When entering cargo tanks of oil tankers, or bunker tanks, or anything tank that has carried combustible liquids, the surveyor must be careful and ensure that the tanks have been tested before entry.

For Crude Oil Washing, the oxygen content has to be less than 8 per cent. If entering a cargo tank that has been cleaned the surveyor must make sure that the tank is well ventilated, because the oxygen level in that tank will be below 8 per cent and well below the 20.8 per cent minimum. It has to be ventilated, to avoid any pockets of low oxygen.

For toxic levels (this applies more to chemical tankers) you have to follow the rules that will be discussed later.

With a very sour crude oil, there may be high contents of hydrogen sulphide, which is the bad egg smell remembered from chemistry at school. It requires only 10 parts per million for it to be dangerous. When entering a tank, if the surveyor notices that smell, verify the safety of the tank.

If benzene is present, again only 10 ppm is needed. Please refer to the attached notes on this slide, which contain additional information to be taken into consideration. This may be briefly explained as follows: all vessels should have a safety data sheet for the cargoes that they are carrying. These apply not just to the various cargoes, but products such as fuel oil, lubricating oil, boiler chemicals, etc. The data sheet shows the necessary characteristics of the material, as well as information for safe handling, and actions to be taken into the event of spillage. It also provides information on first aid and the tolerance vapour limit (TVL) in ppm.

The TVL is a maximum concentration of the chemical that can be safely inhaled: once that level is exceeded it is dangerous. The surveyor must bear in mind that it can be dangerous to his health. He can be permanently injured by it, or even killed.

Some chemicals require antidotes to be carried on board. If he is are carrying out a survey on a chemical tanker that has carried or is carrying dangerous cargoes, he must be extremely careful in case there is any residue or leaks from an adjacent tank. Everyone should be familiar with the chemical in question, and with safety requirements. The Captain will have a log of cargoes carried, the surveyor must check this as part of his documentation check and before he commences his surveys.

Spaces which are low in oxygen (i.e. less than 20.8 per cent) include heavily corroded ballast tanks. A reduction in the oxygen level can occur as rusting is a process of combustion, which absorbs the oxygen present in the atmosphere, forming carbon dioxide. If there is a badly corroded ballast tank, which has not been properly ventilated, there can be pockets of air which contain substantially less than the 20.8% minimum.
Similarly, if ballast tanks are partly filled with seawater, and this has been sloshing around, the seawater will absorb the oxygen, and again there can be a reduction in the oxygen in the atmosphere. The same applies to fresh water tanks. So when going into these tanks, if there is water present, he must be careful, and make sure that the tank has been properly ventilated.

Void spaces are another area that can cause concern. These have probably been coated, the compartment is closed and rarely visited and ventilation is limited. When entering such a compartment that has not been properly ventilated, it can be dangerous.

Entering any of the double bottoms, the surveyor should always ensure that there are two manholes opened, so that there is a natural current of air through the compartment during inspection.

Be careful when going into the crankcase of a main engine that have just been stopped. The air inside the crankcase can be very low in oxygen, the surveyor should make sure that the crankcase is well ventilated before entry with at least two doors removed.

When entering confined spaces, always check when they were opened, how long they have been ventilated, and the ventilation arrangements during the survey. If it is a compartment that is likely to contain gas, giving off flammable or dangerous gases, there must be continuous ventilation and regular checks

Pay attention to the surrounding compartments, because if there is a crack in the bulkhead, even only a small one, and the adjacent tank contains a hazardous chemical, this can be very dangerous, because small amounts of chemicals can produce a lethal atmosphere. When boarding a chemical tanker in particular, always check void spaces around LNG tanks. Again, be very careful.

Check the nature of the last cargo contained in the cargo tank. What is the condition of the tank, if it’s a ballast tank, is it badly rusted, and so on? All these points must be borne in mind prior to his entry he must make sure that everything is all right. It is too late when the surveyor collapses in the bottom of the tank to realise that there is a problem.

When going into any confined space, the surveyor must verify the communication arrangements. How does he communicate with the outside? If there are problems, he needs to raise the alarm as quickly as possible, and so it is necessary to have an efficient form of communication. Before entering a compartment, or tank, always review the tank entry permit or certificate. When was it issued? When is it valid to? By whom was it issued? Equally important is when the compartment has to be verified again, because if the survey will extend past the time of verification, the surveyor should insist on the verification being done before he enters the tank. This is very important for his own safety.

Tankers have what is called ISGOTT (International Safety Guide for Oil Tankers and Terminals) Regulations, these must be observed whenever he is on board the ship. They lay down very strict regulations with regard to tank entry, operational visits, cleaning tanks, and so on. These regulations apply when the ship is alongside and when it is at sea. Great care should be exercised that these regulations are very carefully followed.

Check the isolation of the compartments. Inert gas lines should be blanked, or valves closed, marked, and secured. The surveyor should always make sure that there are two valves between him and any pressure. If one valve is leaking, he could be in a serious situation before he realises it.

The pressure vacuum valve lines should be blanked, or closed, marked and secured. If he is in doubt about a valve and its condition, he must insist on blanks being inserted. The crew must make sure that they are removed on completion.

The same applies to the cargo, ballast and drainage lines. The surveyor must always make sure that there are two valves closed because he doesn’t want to be inside a cargo tank when somebody makes a mistake, and the wrong valve is opened and oil or ballast or oily ballast is allowed to enter the tank. This bring would bring in a lot of gas as well and it can be extremely dangerous and harmful. If in doubt they should be blanked off as necessary?

The surveyor should ascertain the contents of the adjacent compartments. If they are they filled with toxic or flammable material precautions should be taken because there could be dangers due to cracks or leakage into the compartment being surveyed.

At sea or in harbour, the captain or a person assigned by him will issue the entry permit for the compartment. That person should be trained, and should have suitable equipment to verify the condition of the air. The equipment should be tested periodically, to verify its accuracy. The instruments must be periodically tested by an approved organisation.

The surveyor must make sure before he goes into a compartment, that its access has been authorised by the right person, and that the equipment he has used has been properly tested. When entering dangerous compartments where even an extremely small amount of gas is present which would be seriously harmful to your life, it may be necessary for you to wear breathing apparatus. In this case, make sure that the apparatus is in good condition, the lifeline is properly secured, and a means of communication arranged.

Adjacent spaces or associated areas are considered as dangerous spaces, and every time he enters into one of them, there must be a gas‑free certificate for safe access. This usually lasts for about three hours, assuming normal ventilation, but the certificate must be valid for the duration of the survey.

Spaces designed to carry toxic materials ‑ obviously including loading areas, because there can be toxic material present through leakage of the loading lines ‑ must be considered as dangerous. If the toxic gas requires that the surveyor wears a breathing apparatus, then he must do so. There is special equipment for testing toxicity present in the compartment. These are known as Draeger Tubes, there must be one type for each of the various chemicals or materials carried. The ship should have an adequate supply of these and should be used for testing prior to access.

A compartment can have sufficient oxygen, but it may contain a toxic gas that will still kill. The surveyor must make sure, depending on the type of vessel and the cargoes that have been carried, about the condition of tanks before he goes in.

When entering boilers, a similar problem can occur. When both manholes have been opened, and the boiler well ventilated, there should be no danger. But the surveyor should not go into a boiler with only one manhole open, unless it has been very well ventilated.

If there are other boilers on line, it is vitally important that he checks that all valves are closed between him and the other boiler. There should again be at least two valves. This is particularly true in the case of high‑pressure boilers. In fact, it may be necessary to insist upon on a suitable blank being inserted, to prevent the possibility of any superheated steam leaking into the boiler when conducting a survey. Steam will also kill you, not just from suffocation, but from scalding.

The captain or a person assigned by him will issue the entry permit for the compartment when the vessel is at sea or in harbour. That person should be trained and have suitably calibrated equipment to verify the condition of the air. In port, repair yard this would normally be issued by a Certified Marine Chemist or Industrial Hygienist. The surveyor must not be involved with the issuance of Safe Entry Certificates. This will avoid the surveyor being held responsible in case of an accident.

Safe Working Practice (A) 

The person shall test all spaces to be entered using a calibrated, direct reading instrument for the following:
Oxygen Content
Flammable gases and vapours
Potential toxic air contaminatnts
Hydrogen Sulphide (where applicable)
On completion he should issue an entry permit that contains the following: date and time of test, space tested, results (oxygen, combustible gas, toxics, visual examination), instrument used and date of its calibration, name of competent person.

Safe Working Practice (B) 

In addition to the Safe Working Practice (A), extenuating circumstances may require the following:

Persons with operational Self Contained Breathing Apparatus and life lines. Persons to be stationed outside the tank with lines of communication established and clearly understood.

The surveyor to be provided with an Emergency Escape Breathing Apparatus.

A competent person equipped with operating atmospheric monitoring devices.

Remember the surveyor must never go into a compartment without proper communications and security. Safe working practices must be followed very carefully.
If the surveyor goes rafting in a cargo tank of a tanker, to perform the close‑up survey of the cargo and ballast tanks, the raft must be in good condition with sufficient number of compartments to provide adequate buoyancy and stability in the event of any damage and rupture. It must be made from heavy-duty material.

The tank must be suitable for rafting in that it is not too narrow or the structure such that it would easily damage the raft.

The surface of the water must be calm and free from waves. Any swell, the water level must not be expected to rise more than 0.25 m. No tank should be entered if filling is still in progress, the water level must be either stationary or falling.

The surveyor must check that the surface of the water is clean, and that there is no oil present. Even a small film of oil will give off gas, which could have a serious effect on the condition of the air in a confined space like that.

With the ship rolling slightly, or the movement of water inside the tank, oxygen will also be absorbed more quickly.

All conditions of entry into a confined space must be observed. The entry permit must be valid for the duration of the survey.

The level of the water should be such that the surveyor never puts himself in the position where he could be cut off. In other words, if the level of the water in the ballast or cargo tank reaches the level of the lower edge of the underdeck beams, the peak beams, this is too high, and he should not go in. During the survey, if the surveyor sees that the level is rising he should exit as quickly as possible. Remember, the water level should be stationary or falling to avoid being trapped in the tank. At no time should the water level come within a metre of the deepest underdeck web.

Any communications with the inert gas system or pressure vacuum system should all be blanked, or two valves must be closed, marked and secured.

Obviously, before going into any compartment, a safety meeting is conducted with the personnel to discuss communications, safety, and recovery of people in an emergency.

The lines of communication must be tested and suitable for the compartment being entered. Ensure adequate safety lighting available, as the surveyor will not be able to see defects if the lighting is poor. The raft should be properly secured, to ease retrieval.

There should be somebody on the ladder who can see the raft at all times, and of course all personnel on the raft should be fitted with lifejackets and hard hats.

Whenever the surveyor enters any tank the rescue equipment should always be immediately available. It should be outside the tank, adjacent to the entrance, so that in any emergency it can be used immediately, and people rescued quickly. Speed is of the essence. The surveyor should check that it is in position before he enters the tank.


Special Thanks to Capt. Harry González