Análisis del procedimiento para la evaluación y jerarquización de

CAPÍTULO 2. DETERMINACION Y CLASIFICACIÓN DE ATRACTIVOS

2.2 Análisis del procedimiento para la evaluación y jerarquización de

SECTION 6

Engine Special Survey / Continuous Machinery Survey

6.1 General

6.1.1 When a ship is first surveyed for entry into class, the Surveyors should enquire from the owners whether they wish to carry out the machinery surveys on a continuous basis and inform Head Office accordingly. A complete list of surveyable machinery items must be prepared (Form ML-M) and forwarded to Head Office along with the class entry report (Form CL-1). A copy of the previous survey cycle dates issue by the previous Classification society should also be forwarded, if available.

6.1.2 When machinery is to be examined on the Continuous survey basis, the intention is that, so far as practicable, approximately 20% of the surveyable items should be examined each year and that any individual item is surveyed once in any five year period.

6.1.3 The Continuous survey machinery date will be the same date as the Hull special survey date. Hence, there should be no outstanding machinery item for survey when the hull special survey is completed.

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6.1.4 Whenever it is known to Surveyors that a ship will remain in port for some considerable time (during dry docking or when extensive repairs or alterations are being effected to the hull or machinery), the opportunity should be taken to progress the continuous surveys as much as possible.

6.1.5 Under certain circumstances, certain parts of machinery may be surveyed and overhauled by the ship’s Chief Engineer while the ship is at sea or at a port where International Register of Shipping Surveyor is not available. This is applicable only to ships being surveyed under the Continuous Machinery system. In all such cases, the Surveyor is expected to carry out a confirmatory survey before accepting the item. The Owner’s should be requested to contact Head Office for further details regarding this system.

6.2 Scope Of Survey: On the occasion of class renewal survey the machinery, electrical installation and safety equipment plus classed special equipment are subject to detailed inspections and tests for a new period of class. In addition to checking the ship safety certificates and class papers, the work records, measurements reports or logbooks on board are inspected as far as possible. The ship‘s management must be questioned regarding defects or breakdown known to them and inspect repair and maintenance work. The machinery is subject to a general inspection to establish the state of maintenance. The surveys should include all classed components of the machinery and the electrical installation. Due to wide variety of machinery used on board it is impossible to advise specific instruction for each type of machinery. While general principles are enumerated here surveyors are advised to follow the manufacturer's requirement/recommendations and their expertise in the field to evaluate condition of machinery/equipment.

6.2.1 Main engines

6.2.1.1 For oil engines; pistons should be dismantled to facilitate complete examination in view of the rapid wear usually experienced. Liners are to be inspected for incipient cracks in the area of the liner collar bearing surface; in the case of two stroke engines also in the area of scavenge-air and exhaust ports. Liner wear is to be measured and recorded. The permissible wear may vary with engine type, however as a broad guide, cylinder liners must be recommended to be renewed when worn one percent of the bore (reference should also be made to engine builders recommendations). Cooling water passages to be examined for fouling and corrosion.

6.2.1.2 Pistons of oil engines may be found cracked in the crowns or at the back of the ring grooves. Piston rods should be carefully examined in way of crosshead attachments, and at the inlet and outlet holes for cooling water or oil. Suitable crack detection methods should be used, if considered necessary. The ring groove clearance is to be measured and recorded

6.2.1.3 The cylinder block is to be inspected in the area of the liner bearing surface to check the surfaces are in good order and for incipient cracking. Cylinder heads are to be inspected for incipient cracking around the valve seats, on the cooling – water side for fouling and corrosion. Inlet, exhaust, starting and safety valves are to be checked for wear and regarding the state of maintenance.

6.2.1.4 The crank web deflection is to be checked before and after dry docking, a crankcase inspection is to be carried out and the clearances of the main, crank and crosshead bearings, the slide ways, the axial clearance of the guide bearing to be measured insofar as this is possible. If the results are satisfactory, dismantling of the bearings for examination may be dispensed with. It can be assumed in practice that if the condition of the big end bearings is satisfactory and the lubricating oil system intact, the condition of the main bearings also will be satisfactory.

6.2.1.5 Crankshafts should be examined for possible cracking, particular attention being paid to the surfaces close to oil holes and where pins and webs are forged or cast in one piece, the undersides of the crankpin fillets. Pins and journals, which have been subjected to overheating and scoring due to wiped bearings, should be carefully examined for surface cracking. The surfaces should also be checked for surface hardening. The webs of built or semi built

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crankshafts should be examined for movement of the shrink fits and the reference marks should be checked. Webs and bolted on balance weights should be examined at the same time as crankpins. Crankshaft alignment must be re-checked after any major repairs, additions and/or alterations to adjacent parts of the ship’s structure.

6.2.1.6 Bed plates, framing and entablatures of fabricated construction should be examined for possible cracking in way of welded joints, particularly at the girders under main bearings. Any repairs should be reported to Head Office.

Unless repairs are of a minor nature; the repaired areas must be examined at subsequent annual surveys.

6.2.1.7 The seatings of main engines and thrust blocks should be examined, together with holding down bolts, their tightening torque and chocks. Chocking arrangement should be checked for broken bolts and loose chocks. Resin chocks may be found crushed or distorted and should be renewed after the bedplate is realigned. Distortion of bedplates will produce misalignment of crankshafts, and where such conditions are suspected, the condition of the bedplates should be checked by straight edge, sights, taut wire or other available means.

6.2.1.8 Where torsional vibration dampers or detuners are fitted, they should be inspected, where applicable, for broken springs or other defective parts.

6.2.1.9 The camshaft including bearings and drive is to be inspected. In the case of reversing engines, the reversing gear also is to be inspected. Governors and fuel pumps including their drives are to be checked.

6.2.1.10 Exhaust gas turbo-chargers are as a rule serviced and overhauled by specially trained personnel from the makers or a specialist firm. The records on board should be checked to ensure that maintenance intervals have been adhered to regularly.

6.2.1.11 Maneuvering devices (starting and reversing devices) plus engine monitoring and safety equipment is to be checked.

6.2.2 Auxiliary engines: Auxiliary engines are generally examined in the same manner as main engines.

Surveyors need not rigidly adhere in all cases to the main engine survey requirements in deciding the amount of opening up necessary, particularly with small engines, and provided they are quite satisfied that the auxiliary has been well maintained. If regular maintenance is proved and the appearance is satisfactory, it may be considered sufficient if a crankcase inspection is carried out, possibly in conjunction with measuring the crank web deflection.

Additionally, a trial under load and a check of safety and monitoring equipment should be carried out. If for any reason, it is proposed that a ship should sail with one or more of the auxiliary electrical generating sets out of action, Surveyors should ensure that there is adequate reserve electrical generating capacity. In these conditions, provided there are at least two generators in good order, each of which can carry the essential sea load, repairs of any additional generator may be deferred.

6.2.3 Gearing: Each pinion and wheel should be checked separately during one complete revolution and the teeth carefully examined for cracks, pitting, scuffing or any signs which might indicate that pinions and wheels are out of alignment. Any available lubricating oil analysis records should be examined; in particular the results from spectrographic analysis of wear elements. Flexible couplings between pinions and rotors and between pinions and wheels of double reduction gears should be carefully examined and any sign of unusual wear investigated since this may indicate lack of correct alignment. Gear cases of fabricated construction should be examined for possible cracks in way of welds. Thrust bearings are to be inspected as far as possible and the axial clearance measured. If the thrust bearing embodies a lube oil cooler, its tightness is to be checked by a hydraulic pressure test.

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6.2.4 Pumping and piping arrangements

6.2.4.1 At the Surveyor’s discretion essential pumps should be opened out sufficiently to enable the Surveyor to establish the condition of cylinders, plungers, casings, impellers, valves etc. All seawater pumps must be opened up and surveyed. For other pumps, at least one pump of each type (fuel oil, lube oil, fresh water etc) should be opened up for survey. Lubricating oil, gear oil and fuel pumps as a rule suffer little from wear. Coolers and pressure heaters should be tested when considered necessary. Safety valves and other similar devices fitted on pumps, heaters etc., are to be examined to ensure that they are in efficient condition. Bilge suction lines should be tested by pumping water from the various holds and engine room bilges and it should be seen that strums or strainers are fitted in the holds and that sounding pipes are in order. Where non return valves are fitted at or adjacent to the open ends of bilge suction pipes in holds they should be opened out to see they are in good working order and of a design which does not unduly obstruct the flow of water.

6.2.4.2 The survey of pumping arrangements should include a general examination of all essential piping, fittings, valves and controls. It is important to see that emergency suction valves and connections are free and not choked.

Particular attention should be given to seawater piping systems. The extent of survey will depend on various factors such as the age and service of the ship, the materials of the pipes and valves as well as the onboard maintenance.

Normal inspection methods involve hammer testing, visual examination and pressure testing, however where judged necessary ultrasonic thickness measurements should also be taken. Any temporary repairs should be specially examined. The Surveyors must be fully satisfied with replacement pipe sections or permanent repairs completed.

Flexible connections in seawater, lube oil and fuel systems must be of flame resistant material. This applies in particular to pipe connections to diesel engines. It should be ensured that the non-return devices required for the bilge and ballast systems are fitted and operative. Heating coils in oil tanks, cargo tanks and receivers are to be subject to a hydraulic pressure test to 1.5 times the maximum allowable working pressure but at least to 4 bar. The safety of operation of pressure reducing and safety valves in pipelines is to be checked. In the case of tankers the pipes of loading and unloading arrangements including the safety devices are also to be inspected. The tank venting systems (overpressure valves, vacuum valves, flame traps) are to be inspected in the opened-up condition and the set pressure checked (in collaboration with an expert firm).

6.2.4.3 Emergency fire pumps should be tested under working conditions and provided they operate satisfactorily and deliver the required supply of water at the required pressure, they need not be opened up. The operation of any remote control gear for the sea inlet valve should be tested. Where emergency fire pumps are driven by diesel engines, the engines need not be opened up provided they function satisfactorily and it is demonstrated that they can started when cold.

6.2.4.4 In ships carrying flammable liquids having a flashpoint below 60⁰ C, the cargo pumping system must have no direct communication with the machinery space, or with the oil fuel bunker lines and Surveyors should ensure that any alterations to the piping system made at any time do not infringe on this requirement. Gas tight glands fitted to pump shafts, which pass through pump -room bulkheads should be examined to ascertain that they remain efficient.

The bilge drainage system in pump rooms should be checked. Clean ballast pipes passing through cargo oil tanks should be hydraulically tested and proved free from leakage.

6.2.4.5 Steam pipes are to be inspected externally. Random checks of internal condition particularly in the region of bends, or more thorough examination may be required.

6.2.5 Compressed Air Systems

6.2.5.1 Compressors should be opened up and the working parts examined. It is important to ensure that the tubes or coils of air coolers are in good condition and when considered necessary a hydraulic test to 1.25 times compressed

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air discharge pressure in the coils/tubes should be applied. Coils may be found locally thinned due to rubbing against supports or casings or there may be internal erosion at bends, which may be detected by slight hammering.

6.2.5.2 Air receivers should be examined internally together with mountings. When size of the openings restrict internal examination, a hydraulic test to 1.05 times the working pressure should be applied

6.2.5.3 It should be ensured that all filters, oil separators, safety devices, bursting discs, fusible plugs and relief valves on compressors are in good condition and that drainage arrangements throughout the compressed air system are satisfactory. Many explosions have taken place because relief valves or other safety devices have been rendered inoperative by paint or dirt or by using bursting discs of incorrect material.

6.2.6 Where bridge remote controls are fitted to main propulsion and/or auxiliary machinery, they should be tested to establish that they are in good working order. It should also be ascertained that normal hand/local controls are available and in working order and that efficient means are provided to indicate which station is in control.

6.2.7 The means of communication between the bridge and the engine room and the bridge and the alternative steering position must be tested under working conditions.

6.2.8 Steering Gear

6.2.8.1 The steering gear is to be subject to a functional test and the log of test drills required by SOLAS is to be examined. System relief valves are to be checked for set pressure and operation. If auxiliary or emergency steering systems are provided, they are also to be tested. A good assessment of the condition of the hydraulic pumps and the steering gear is possible if the hydraulic pumps are made to operate against the blocked gear. If the pumps then reach their full operating pressure, it can be assumed that they are in a satisfactory condition. Also the following are to be checked: seating bolts, tightness of system, functional test with one hydraulic pump, with spare pump, with both hydraulic pumps; emergency operation (hand rudder); overload protection (slipping clutch, safety valves); restriction of the rudder angle to 35 degrees in normal operation (e.g. limit switches); operation of gear via the emergency switchboard; rudder angle indicators; means of communication between steering gear compartment and bridge and alarms.

6.2.8.2 Access to all mechanical parts of the system including handrails and anti-slip surfaces is to be verified.

Steering gear compartments may be located in areas subject to vibration. Therefore, the piping should be examined for possible cracks, particularly at areas of stress concentration, e.g. flange attachments. Unsupported lengths of piping should be secured effectively, and flexible hoses examined for signs of damage. Particular attention should be paid to leaks, glands, connections, storage tanks and fittings, all mechanical linkages, pins and their securing arrangements, of the main system and control system, together with an examination of holding down arrangements of the gear to the ship’s structure.

6.2.9 Anchor windlass: The gearing is to be examined through inspection openings. The clutches, brakes, chain sprockets and chain stoppers are to be checked. In the case of hydraulically driven windlasses the hydraulic pumps, the pipelines and the functioning of the overflow valves are to be checked. Electrically driven windlasses are to have the functioning of the slipping clutch and of the electrical overload protection checked.

6.2.10 Electrical installation: Examine all accessible cables and cable trays for damage, aging, damaged fastenings and fouling especially by oily or greasy substances. Check bulkhead and deck lead-through for the condition of the sealing compound and filler of the glands for single cables. Check the protective earthing of machinery and appliances. Check effectiveness of explosion proof fittings in dangerous areas. Examine generators and main electrical motors for proper maintenance and cleanliness of current-carrying internals. Heavy fouling can be detected when measuring the insulating resistance. Heavily fouled machines should always be dismantled and cleaned and

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overhauled by specially trained personnel. Power unit couplings of shaft generators are to be examined.

Switchboards are to be inspected for the general state of maintenance and proper operation of the switches and instruments (ampere, volt, frequency, power meters, synchroscopes, circuit breakers, fuses, press-buttons, indicator lamps). In the case of older and open switchboards not erected in separate compartments a special lookout is to be kept for fouling of the current carrying internals. For switchboard operating at 50V or above, insulating floor covering is to be fitted in front of and behind the boards (wooden gratings or rubber mats) and the front & back of the switchboards should have proper cover. Such switchboards should also have handrails in proper condition and warning notices giving the voltage and drawing attention to the danger must be fitted. Storage batteries and their charging arrangements must be examined for proper maintenance and operation. It is to be verified that no changes have been made to the operationally safe installation, the site or the equipment. An examination of protective boxes and lockers, supports against slippage, drip trays, ventilation and proper cable connections is to be carried out.

Surveyor should ensure that warning notices prohibiting use of open flames or smoking have been applied to boxes, lockers or compartments. Insulation resistance (Megger test) measurements must be carried out comprising all parts of the installation (electrical machinery, switchboards, lighting circuits, cable systems, etc.). Repairs must be carried out when insulation resistance values are below the following: -

Electrical machinery : 0.5 Mega Ohms.

In document Evaluación multicriterio de los recursos turísticos del Centro Historico de Santa Clara (página 36-42)