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Product Catalog AC Marine

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14.09.2021

Sea trials

On completion of the HAT, the ship goes for trials. At sea for large ships, inland at sufficient deep and wide water for smaller ships. The electrical installation can then be tested under 'nor­mal' conditions and/or full load, on full speed, without ground or channel effect, what is normal­ly not possible at the outfitting quay. Without speed, alongside, the propulsion system quickly comes in overload conditions.

   1. Sea trials

During sea trials the final tests are carried out before delivery of the ship to the owner. Sea trials prove the specified per­formance of the ship to the owner as well as demonstrate that the ship is capable of performing con- formto the minimum requirements as determined in SOLAS.

Propulsion equipment is to be test­ed under working conditions and operated in the presence of the surveyors to their satisfaction.

Owners' requirements, such as speed, fuel consumption, noise levels, etc. are to be tested at full operating conditions or at whatever agreed figures or circumstances provided in the building contract. For cargo ships maximum figures for sound or noise are given in SOLAS; for yachts and passenger ships there is a totally different list of figures.

Sound and vibration levels form a great part of the conditions for people's comfort onboard ships and these have to be verified under op­erational conditions.

All necessary parameters such as pressures, temperatures under dif­ferent load conditions of the main engine are collected and recorded. A booklet with all these data is pro­duced and remains the reference throughout the lifetime of the ship.

On completion of the seatrials, the SAT, when the ship is considered completed is all respects, the ce- rificates are issued, as far as not already issue for completed items. With the necessary egards and of­ten festivities, the initial Class cer­tificates for Hull and Machinery are handed over. When all necessary other certificates are on board, the ship is allowed to take cargo and to leave port.

   2.  Periodical surveys

However when the ship is in ser­vice, to maintain the validity of the certificates, periodical surveys have to be carried out. Annuel survey, intermediate survey, and special survey, together with other com- pulsary certificates in a five years cycle. The basic annual electrical survey consists of the following tests and inspections, depending on the type of ship. For example:

   2.1. General

- Testing of all bilge level alarms
- Testing of all watertight doors (operation and alarms), general survey conditions of watertight sealing of electrical equipment when this is intended to be used in submerged conditions
- Testing of main and auxiliary steering gear systems inclusive of alarms
- Survey of all escape routes, route signs, illumination low level lights
- Testing of communication sys­tems between bridge and en­gine room and emergency con­trol positions
- Testing of remote controlled valves and indications
- Inspection of main and emer­gency switchboards and as­sociated cables. Examination under normal operation condi­tions. Testing of automation, black-out start, power depend­ing start, power management systems, automatic sequential restart systems, non- essential tripping systems. Electric safety inspection, earthing of electrical equipment, especially in wet or dangerous areas
- All ships: General inspection of alarms and safety devices as well as autostart of standby generator and sequential restart of essential auxiliaries under normal service conditions
UMS ships: General inspec­tion under working conditions of automation systems such as standby pumps and auxiliaries.
Sample tests of alarms inclusive of bridge, mess room and cabin alarms. Safety timer/dead man alarm systems. Survey as per approved test schedule. Testing of bridge control systems and bridge engine room communi­cation systems.
Navigation and nautical equip­ment. General inspection of all equipment under normal opera­tion
- NAV 1 Ships, In addition to general inspection under work­ing conditions of bridge equip­ment additional alarms and in­dications, also safety timer and cabin alarms. Survey as per ap­proved test schedule.
- Radio I GMDSS / External com­munication survey
- Crew safety systems. General alarm and emergency lighting system, emergency generator automatic start and if emergen­cy source of power is a battery, a load test of this battery.

  Father in addition to 2.1:

  2.1.1. Ships transporting dangerous cargo in bulk

Dangerous cargoes in bulk. In­spection of equipment in dan­gerous areas in relation to the gas group, temperature class and external damage, if any.

- Dangerous dusty cargoes. In­spection of equipment in dan­gerous area, type of enclosure, protection class, eventual exter­nal damage.

  2.1.2. Tankers

-  Dangerous liquid cargoes. In­spection of equipment in dan­gerous areas, in relation to gas group, temperature class and eventual external damage. Gases from some cargoes are heavier than air and thus form a layer on deck or in any space under the deck.

 Liquefied natural gas and liq­uefied petroleum gas carriers (LNG and LPG ships).

Liquefied natural gas is lighter than air, while liquefied petro­leum gas is heavier than air. Inspection of equipment in dan­gerous areas gas group and temperature class to be verified as well as inspection for damage to ship or equipment.

  2.1.3. Passenger ships

-  Ship safety systems

-  Passenger safety systems. General alarm, public address, emergency lighting, transitional lighting systems and low level lighting systems. Batteries and UPS capacity tests are required. Automatic start of emergency generator and operation of as­sociated equipment as fans, fire flaps, air louvres, to be demon­strated.

  2.1.4. Car ferries with bow and stern doors

-  Door alarms and indications, water level alarms, closed cir­cuit TV monitoring systems (CCTV)

-  Additional lighting systems for crew and passengers

Equipment in dangerous areas, for instance the lowest 45 cen­timetres above the car decks where cars are stowed with pet­rol in their tanks are considered dangerous areas. Also attention for equipment under ramps and swing decks where cars can be stowed. Minimum requirements for equipment on cardecks, etc. above this 45 centimetre layer is protection class IP 55. Car deck ventilation must have at least 10 air changes per hour.

  2.1.5. Dynamic positioned ships

Annual Survey under operational conditions, which means an annual DP trial at a convenient to demonstrate the ope the control system completed with a survey of the total p system, often diesel eleccric. Sur­veys and tests have to b out as per ship-specific test schedule. Special attention for UPS capacity tests. The the tests is often the FME mode and effect analysis.

  2.1.6. Small ships and yachts

- Basic electrical installations;
- Automation ;
- Equipment in dangero where all sorts of e running on petrol, is stored. For requirements see car decks. The ventilation must perform at least 10 air changes per hour. Gas detection must be fitted to an alarm and ment not suitable for this envi­ronment must be switched off.

  2.2.  Complete five year survey electrical installations

Every five years the electrical instal­lation of a ship must be subjected to a special survey, equal to an an­nual survey along with the following tests and inspections:

- Electrical insulation resistance measurement of all cables and equipment, motors, generators, switchboards and all consumers, galley, laundry. Also high voltage cables and consumers, if any. Fittings of main and emer­gency switchboards to be in­spected, which means checking of connections either by torque wrenches or by thermal inspec­tions under load, using infra-red camera. Copper bus bars are relatively soft, the torque when setting bolts is therefore, impor­tant. Checking of bus-bar resist­ance by special low resistance measuring equipment. Testing of circuit breaker settings and inspections of contacts. Resist­ance measuring of contacts of vacuum circuit breakers. Cali­bration of circuit breaker set­tings and testing of non-essen­tial tripping circuits. General inspection of switchboards.


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