RUDDER WEAR DOWN

This refers to the measurements taken generally during a docking period to indicate excessive wear in the steering gear system particularly the rudder carrier. The significance of this is that for ram systems excessive wear can lead to bending moments on the rams. For rotary vane systems it can lead to vane edge loading.The readings taken are offered for recording by the classification society.

Trammel

This takes the form of an 'L' shape bar of suitable construction. When the vessel is built a distinct centrepunch mark is placed onto the ruder stock and onto a suitable location on the vessels structure, here given as a girder which is typical. The trammel is manufactured to suit these marks As the carrier wears the upper pointer will fall below the centrepunch mark by an amount equal to the wear down.




Rudder Clearance

Pads are welded to the hull and rudder. A clearance is given ( sometimes referred to as the jumping clearance). As the carrier wears this clearance will increase.



Steering gear Clearance

Direct measurement can be taken from the steering gear assembly. Shown below is one example, here the clearance will be seen to reduce as the carrier wears and impact his has on the system can be directly judged


Rudder wear down measurement:(Ram type Steering Gear ) 
At sea: 
1)Jumping clearance or bouncing clearance,measured between swivel block and upper ram fork end. (lmit is 19mm) 
2)Wear down clearance,measured between swil block and bottom ram fork end. (limit is 12-19mm) 

At docking: 
1)Bouncing clearance: measured betwen top ofrudde and jmpng bar. 
2)Wear down clearance: beween the bottom of rudder and reference mark.
Sunday, August 30, 2015
Posted by sanjay swain

REASON OF TURBOCHARGER DAMAGE

Diesel Engine Exhaust Turbocharger Failure 

Turbochargers are among the foremost technologically advanced engine element aboard ship. impeller blades of a medium sized turbocharger often rotate at the maximum amount as 400 revolutions per second. The outer edges of the rotor blades therefore move at 1.5 times the speed of sound.

In the method, the turbocharger digests contaminated exhaust gases of up to 700 degrees centigrade. Thus, the turbocharger may be a terribly sensitive piece of high-speed machinery incessantly serving in harsh conditions and underneath extreme strain. Being on the receiving end of gas flows, turbocharger damages are typically caused by the failure of varied upstream elements.


(1) Diesel engine inlet pressure to reduce main reasons:
(a) the compressor of the filter contamination.
(b) the impeller and vanes diffuser contamination.
(c) the supercharger turbo memory have more carbon deposit, spin resistance increase.
(d) the inter-cooler contamination, increased intake resistance.
(e) turbine exhaust not clear, this is because the pipe blockage, deformation caused by rotor speed rise is  not high.
(f)supercharger outlet pressure drop suddenly, it is because of bearing damage caused by.


(2) Compressor surge main reasons:
(a) diesel engine emergency cut-off or sudden unloading (urgent throttle back).
(b) the atmospheric temperature changes cause surge. In the summer of the supercharger with test, in winter could happen surge, this is because the temperature change make working point change and cause.
(c) compressor contamination, especially vanes diffuser contamination.
(d) a engine plant 2 sets of supercharger, Shared a piece of inlet manifold, when a cylinder does not work, can lead compressor surge.


(3) Diesel engine inlet pressure is too high. Generally speaking, the inlet pressure is too high in the supercharger itself is not the problem, but by the engine of the cause, the main reasons are:
(a) the vent valve leakage.
(b) because of engine fuel injection timing inappropriate or other causes for combustion period is too long, to drive a turbine heat increase, speed up, inlet pressure increase.


(4) Produce continuous abnormal sound: this kind of failure is due to the majority of rotor and shell as a result of the collision. Due to the rotor and shell assembly clearance is small, if installation misadjustment or bearing serious damage, then hitting.


(5) The lubricating oil temperature is too high (above 105 ℃) of the main reasons:
(a) the turbine oil, gas seal damage, high temperature gas into the oil chamber.
(b) the bearing damage.


(6) Oil leakage: compressor seal close to the edge of the impeller is low pressure area, easy to produce the oil leakage fault. Main reasons are:
(a) the lubricating oil return not free. The reason has return line congestion, return line sectional area is too small, pipe joint gasket inner hole diameter less than return line; Diesel engine in the crankcase oil level higher than standard, cause oil return difficult; Diesel engine crankcase ventilation blocking or cylinder seal bad, gas expell, make the crankcase internal pressure rise.
(b) the compressor end O ring damage or material ageing and lose sealing effect.


(c) turbocharger oil inlet pressure is too high. Normal pressure is 0.25 ~ 0400000 mpa, if pressure is higher than 0.6 million mpa, from exhaust muffler nozzle will find from the supercharger turbo end leakage oil.
(d) ring not installed correctly or damage.

Saturday, August 15, 2015
Posted by sanjay swain

ULTIMATE GREEN SHIPS

14 Technologies to Make the Ultimate Green Ship



The Shipping business is departure no stones right-side-out so as to contribute towards a greener marine atmosphere. At each producing and body levels, the maritime business is taking advantage of the newest technologies to make sure that new ships contribute as low as attainable to the world pollution.
Designing a Ship in present times has become a difficult task for currently a ship must be totally complied with new environmental rules and rules. some benchmark technologies have already been developed to achieve the final word goal of building a “Green ship” which might not solely suits the new environmental rules and rules however would additionally leave least attainable carbon foot-prints.

We have compiled a listing of 13 new technologies that if used along would lead to the ultimate green Ship of the longer term. they're as follows:

1.   No Ballast System: Ballast water convention by International Maritime Organization focuses on reducing the transit of sediments and small organisms of one territory to a different through the ballast of ships. so as to forestall this condition, plans of constructing a “No Ballast Ships” is underneath progress. A no ballast ship or similar system will drastically cut back this downside.

2.   LNG Fuel for Propulsion: it's same that LNG fuel is that the way forward for the Shipping business. LNG fuel helps in reduction of pollution from ships, and a mixture of LNG fuel with fuel can cause economical engine performance, leading to fuel saving.

3.   LNG Fuel for Auxiliary engine: Auxiliary engines on ships square measure main sources of power. what is more {they are|they're} one in all those machines that are continuous running aboard vessels. LNG fuel for such engines will drastically cut back pollution from ships.

4.   Sulphur Scrubber System: It’s not much attainable to phase-out usage of standard fuels in ships and thus reducing sulphur or SOx emission from the exhaust could be a answer that will be used extensively within the future. this could be achieved by putting in associate exhaust gas scrubber system whereby the sulphur is washed out from the exhaust gas of the engine leading to reduction of SOx up to ninety eight passed by with alternative harmful particles.

5.   Advanced Rudder and mechanical device System: A simple mechanical device and efficient rudder system will cut back the fuel consumption up to 4 the worries leading to less emission. Advanced styles of mechanical device and rudder systems are developed to not solely cut back the fuel consumption however additionally improve the speed of the vessel.

6.   Speed Nozzle: Speed Nozzles are typically utilized in little provide vessels and tugs to supply power to the ships. along side new style options of cargo ships, they will improve the propulsion potency of the ship by saving power up to approx five the concerns.

7.   Hull Paint: Another vital issue that may increase the fuel consumption of a ship and thus emissions is rising hull properties. Applying correct paint at correct hull space will cut back the resistance resistance of the ship leading to 3-8% of fuel savings.

8.   Waste Heat Recovery System: this technique is already in use for quite your time currently, however creating it a lot of economical will cut back the fuel consumption of the ship drastically up to 14 july of the whole consumption. The waste heat from the exhaust gases is used to heat and generate steam that successively is used for heating storage area, accommodation, heating oil etc.

9.   Exhaust Gas Recirculation: during this system, Roman deity emissions from the engine is reduced by recirculation of exhaust gas from engine cylinder with scavenge air that lowers the temperature of the combustion chamber. Some a part of the exhaust air is re-circulated and intercalary to scavenge air of the engine that reduces the oxygen content of the scavenge air along side temperature of combustion cylinder. With this methodology nox reduction of up to 80th is achieved.

10.  Water in Fuel: The addition of water in fuel simply before its injection into the combustion chamber will cut back the temperature within the cylinder liner. associate economical system for this could lead to nox reduction of up to 30-35%.

11.   Improved Pump and Cooling Water System: associate optimized cooling water system of pipes, coolers and pumps may end up in slashed resistance to the flow. this may cause savings of up to twenty of electrical power of the ship and fuel consumption up to 1.5 %.

12.   Sail and Kite Propulsion System: Sail and Kite system once used along side the traditional system will cut back the fuel additionally as nox, SOx and greenhouse emission emissions by thirty fifth. browse a lot of regarding these inexperienced propulsions system here.

13.   Fuel and photovoltaic cell Propulsion: The cell propulsion utilizes power from a mixture of fuel cells, star cells and battery systems. This helps in reduction of GHG emission to an excellent extent. browse a lot of regarding these propulsion systems here.

14. sandwich plate System (SPS): it's a method of composting two metals plates by bonding it with polymer stuff core.  This avoids usage of steel which needs further stiffening thus makes the structure lightweight weight and fewer vulnerable to corrosion. This technology will undoubtedly play an honest role in inexperienced ship usage method as SPS feature includes superior in commission performance and reduced through life maintenance.
Friday, August 7, 2015
Posted by sanjay swain

WATER MIST IN LARGE MACHINERY SPACES

Water mist systems are extensively used as fire protection of machinery spaces onboard passenger ships, and have almost taken over as fire extinguishing systems after IMO standardized such systems. Water mist systems are documented through full scale fire testing of the manufacturers' solutions. In practice it has been shown that in spaces with a ceiling height above approximately 10m it is necessary with more water mist nozzles to extinguish low seated fires. The IMO-method that describes the test procedures requires that all nozzles are mounted at ceiling level, and gives no opportunity to extrapolate results from fire tests to spaces with higher ceiling heights.
Conventional merchant vessels have large machinery spaces with ceiling heights above 10m. Therefore it is still common to install CO2-systems in these ships, since no alternative extinguishing systems are approved for this application area. Until now several manufacturers of water mist systems have documented that it is possible to extinguish fires in machinery spaces with height up to 10m and a volume exceeding 3,000m3. A research project initiated by IWMA (International Water Mist Association) resulted in a change of IMO's regulations. That means that the test results will be valid also for spaces up to twice the tested volume, but there was not given any possibility to increase the ceiling height.
If it can be shown through testing that water mist systems have sufficient ability to fight fires in larger machinery spaces, such systems will challenge and replace CO2-systems. In practice this means that fire extinguishing can start immediately after a fire has been detected. Today the start of extinguishing may be delayed with 10-15 minutes because CO2 represents a toxic hazard to persons in the machinery space. The CO2 cannot be released before people are evacuated from the engine room and all air supply is stopped and all openings are closed. Every minute with a fire in the machinery space increases the damage to equipment and cables; it has been indicated that the damage increases with €12,000 per minute.
Water mist systems can be released immediately after fire detection, and will quickly cool down the machinery space. Most fires will be extinguished after 10-15 minutes. In addition water mist systems have become popular among engineers and crew because they, besides being possible to use without hazard to people, are easy to test regularly. Water mist systems on passenger ships are often tested every week, and are simultaneously used for cleaning the machinery space. The costs connected to refilling the water reservoir are negligible in contrast to replacement of CO2-bottles after release of a CO2-system.
SINTEF NBL is now working to start projects that can open up for use of water mist system in large machinery spaces, and for this purpose we have the possibility to utilize our large test hall. The test hall is over 20m high and has a total volume of approximately 14,000m3.
Thursday, December 19, 2013
Posted by sanjay swain

DRY DOCKING



DRY DOCKING
·        the major event
·        preparing the vessel for the next 30 months
·        cost

DRYDOCKING MAINTENANCE ALTERNATIVES
·        crew
·        traveling squads
·        shore assistance
·        compare with shipyard
·        heavy work involving high lifts  transportation
·        lowest cost

DRYDOCKING SPECIFICATION (most important document)
·        terms/conditions
·        description of all jobs
·        compiling the specifications as  early as possible

DRYDOCKING SUCCESS FACTORS   (knowing the vessel)
·        good and complete specification
·        planning
·        controlling the yard
·        adequate resources

DRYDOCKING THE SUCCESSFULL DD
·        the specification to cover between 80-90%  of all work
·        no major extra cost
·        within the stipulated time and estimated  cost

DRYDOCKING PREPARATION FOR ENTRY
·        vessel to be free for hot work and   enclosed places to be ventilated as required
·        bunkers / f.water / ballast etc. be suitably distributed to achieve   suggested trim.
·        works in specification identified / marked.
·        supervision duties decided and agreed to.

DRYDOCKING SURVEYS
·         a list of all items to be surveyed is kept ready
·         list of all certificates expiring is ready
·         list of conditions of class to be dealt with is clear
·         list of new applicable regulations to be attended to is available.
·         modifications /fabrications if any as per new regulations should already
·        be in the scope of repairs
·         liase with the surveyor and agree on the scope of inspections / duration of inspections.
·         to keep surveyor informed about the docking surveys and get a list of recommendations at the earliest for completion of statutory  certificates.
·         get surveyor’s approvals for the scope of repairs involving class.


PRE DOCKING SURVEYS
• get the gauging reports verified and establish the scope of steel repairs.
• agree with surveyors’ action plan for crediting of cargo /ballast tanks   for (intermediate/special) surveys
• agree on testing procedures / repair procedures if any and press test of tanks as per    requirements.
• it is advantageous to plan to credit all tanks prior to docking, the trading pattern permitting.
• to credit max possible CSM items prior to docking.

DRYDOCK WORK SCHEDULE
ship staff and yard jobs are clearly understood / planned and carried out without interference
• yard jobs (in process and completion and testing) are properly supervised
• spares supplied to yard by vessel / arrival of new spares etc are properly  recorded and monitored
• decision makings are properly delegated
• onboard timings are suitably altered to get max   productivity.
• shipboard meetings are properly timed to continously   monitor the situation.
• repair teams if any are to be properly utilised and   effectively monitored

dry docking safety
• safety meetings involving yard and ship staff to be properly timed and well attended
• violations of yard guidelines are to be strictly discouraged (hotwork in engine room etc.)
• tank entries etc. are to be done strictly according to procedures and  personnel to be doubly careful while closing openings
• importance to be given to attire.
• extreme care to be exercised while turning engines/operating steering   gear/starting blowers/switching on electrical breakers/prior trials etc.
• systems are to be properly deactivated and rendered safe (depressurise  hydraulic lines/empty oil lines/drain  sea water lines etc)
• boundaries of fuel oil tanks are properly marked
• the tank drain plugs are properly marked / identified and protected from inadvertant opening.
• frame nos are suitably marked on deck/sides and bottom.
• vent pipes are suitably marked/identified.

drydocking economy    
• repairs done through afloat workshops are always cheaper
• most of the specialized jobs are   done thru subcontractors or representatives of OEMs with a surcharge.
• a repair team will always be cheaper if the materials can   be organized cheaply.
• you will loose a fortune if you need to do tank cleaning inside a yard.
• all additional work will be charged at a very high rate.
• the smaller the fabrication jobs/steel jobs on deck--the more   uneconomical it becomes.
• quantities of steel work/pipe work/hull painting etc are to be determined with respect to conditions in tariff like
           • minimum kgs per location
           • minimum meters per location.
           • charges for inway and access work
           • minimum surface (blasting)
           • minimum no of points per location (gauging)

• WATCH OUT FOR THESE DANGER AREAS
          pipe clamps
          transport to workshop
          machining/fabrication items
          cleaning
          ventilations / bilges / services.

 it would be cost effective to take a quote for the following
     - unshipment of rudder
     - renewal of carrier bearing with yard material
     - renewal of pintle bearing with yard material
     - standard tariff for o’haul of motors (kw basis) /pumps (kw basis)/pipes (meter basis)/ testing of pipes (meter basis) /testing of welds (meter basis) / supply of skilled and unskilled manpower (hourly basis) magnaflux / radiography and other tests / staging (tower and block/buildup of pits/reweld bottom plates

• best economy is an outcome of a tight specification

drydocking   commercial

the following important aspects are covered by   the contract document
•       time of completion
•       discount offerred
•       penalty clauses
•       repair specifications
•       repair specifications
•       payment schedule & redelivery of vessel
•       owners rights
•       yards responsibilty and limitations
•       guarantee
•       engagement of subcontractors and surcharge.
•       work done certificates
•       authority and owners representative
•       cancellation clause / terms
•       facilities to be provided to owners representatives
•       change of scope of repairs
•       spares and stowage
•       pilotage tugs etc for shifting for yards convienience
    •       the owners enquiry contains the conditions   of the owners
    •       the yards offer contains the yards rules and conditions
    •       the conditions in the yards offer stand valid even if they are
contradictory to owners   request once the vessel has been stemmed
    •       the areas of contradictions are to be agreed upon / thrashed out prior stemming the vessel.

drydocking technical -  corrosion protection
anodes
-       choice of the correct type and quantity of anodes.
-       replenishing of electrodes for impressed current   systems if fitted.
    -       protection of anodes while painting
    -       correct placing of anodes under guidance from supplier.
-       removal of old anodes

drydocking technical
• steel work
           - inspection of weld quality / fitups
         - keep track of the dimensions and locations (for commercial reasons)


• rudder
            - bush clearance
          - drop
          - sealing 0 rings for the taper surface of the pintles
          - proper cementing of palm bolts
          - water box closing plate water tightness
          - jumping bar /clearance
          - key ways
• propeller
       -  push up and pull up hydraulic pressures (push up curve)
      -  key ways
      - polishing

• anchors and chain-
      - gauging and reversal if reqd
     - cleaning of chain locker and insp


• HULL
      - gauging of stiker plates
      - build up of pits
      - wee out/gouge and build up weld seams of bottom   plates
      - inspection of drain plugs

drydocking technical (machinery)
• cleaning of coolers and heaters
• o’haul of large electric motors
• balancing of rotating equipments as reqd.
• o’haul of machinery as reqd
• recheck alignments of machineries if disturbed.
• remove deficiencies in automation and control equipmen as reqd.

drydocking instrumentation and navigating equipments
• callibration of electrical switchboard meters/other electrical and mechanical measuring devices
• o’haul of main breakers and callibrating safety trips.
• rectify deficiencies in navigating instruments
• rectify deficiencies in safety systems if any.

drydocking prior flooding(important items prior flooding)
-       all tank drain plugs are inspected and vacuum   tested after fitment
-       all anodes are functional
-       sea chest gratings etc are secured
-       correct ballast is taken.
-       inspect rudder (water box) / propeller /rope/ guard
-       all cargo/ballast tanks are clean from remnants of    steel work
-       cargo lines etc pressure tested / pumps are tried out
-       all tank valves (if remote operated) are tried out
-       hatch covers etc and other type of cargo gear are tried out and properly secured
-       all sea chests are properly purged of air
-       all equipment in engine room are tried out
-       main engines/boilers are preheated and ready for trials


drydocking sea trials
• sea trials
     - engines are run to required speed, movements are checked.
     - steering is confirmed to be performing satisfactory
     - stern tube oil is checked for maintaining level.

• the vessel may proceed to sea on   satisfactory completion in some cases


Saturday, October 26, 2013
Posted by sanjay swain

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