• Small but essential maintenance operations

    Small but essential maintenance operations


    Recently we have been reporting on a few of the larger projects we have carried out. These are jobs that show how we can easily adapt ourselves to different situations, even in circumstances that might at first glance seem too complex to allow on-site work.

    This might give readers the idea that we can only assist you when such major challenges come up, but this is not the case. We treat every assignment with the same professionalism and  enthusiasm, whether it is the replacement of a giant azimuth thruster or an underwater propeller buffing.

    This article focusses on some examples of those smaller maintenance operations, which are also dealt with in a skilled and proficient manner.

    Impressed current anode replacement in Le Havre
    When both the port and starboard side impressed current anodes on a 286-meter container vessel were malfunctioning, we sent a diving team to Le Havre to perform an underwater replacement.

    The customer passed on all the necessary information to our technical department and after preparations in our fast response center the equipment was loaded onto one of our trucks and transported to Le Havre.

    The Hydrex team arrived on site and carried out an inspection on the port and starboard side ICCP anodes. This revealed that the anodes on both sides were indeed in poor condition.

    They were therefore swiftly removed and replaced with new ones by the diver/technician team. This restored the vessel’s protection against corrosion.

    Blanking in Dunkirk
    A team of our diver/welders blanked all underwater openings of four offshore vessel to keep them safe during a cold stacking period. This was done in Dunkirk, France,  over a period of four weeks.
    Two hydrographic survey vessels, an oceanographic vessel and an offshore installation vessel were layed up in Dunkirk for a long period. It was essential that they were kept safe during this period.
    Especially the underwater part of the ships needed additional protection against the constant exposure to salty seawater. For this reason we were asked to develop a fast and complete solution to close off all the underwater openings of the vessels including sea chests, overboard valves and box coolers. Between 30 and 40 blanks were installed on each ship, ranging from small 10 x 10 cm plates up to very large 4 x 4 meter ones.

    Speed log installation on two sister ships
    Our teams can very quickly replace any type of transducer without any hindrance to a ship’s schedule. We can however also install them should this be required. This was the case when two 193-meter general cargo vessels needed a speed log installed during their stay in Antwerp.

    Our diving team started the operation with an inspection to determine the best place to install the speed log. They then marked the exact position where the speed log was to be positioned.

    The next step was to install a mobdock over this area creating a dry space within it. Part of the team cut a hole on the inside of the hull to the exact dimensions of the speed log. They then fitted and installed the housing. An oil ring seal was used to closed off the housing from water ingress.

    Simultaneously the rest of the team prepared the wiring for the speed log which was connected to the housing. At this point the mobdock was removed. The wiring was then installed inside the vessel and the speed log was connected to the ship’s electrical system.

    The installation was done flawlessly and afterwards both vessels had a fully operational speed log system on board.

    Propeller buffing increases efficiency

    We have developed a new method of propeller cleaning. The traditional approach in the industry is to let the propeller foul and build up a calcareous growth and polish once or twice a year underwater or in drydock. This polishing is done with a grinding disk and can be quite damaging to the propeller because a substantial amount of metal is removed. This can alter the shape and efficiency, cause roughness and increase rather than reduce friction. It is also a major source of marine pollution which is a problem in many ports.

    We discovered that more frequent, lighter buffing of the propeller is the optimum approach to propeller cleaning. This is done using a different tool to a grinding disk to catch the propeller before a calcareous layer builds up. If done right and done regularly this can result in 5% or even more fuel savings. These savings far outweighs the cost of the propeller cleaning itself. Because the propeller is being cleaned regularly, the cleaning is light and quick. No material is ground away which is good for the propeller and the environment. The propeller is kept in an ultra-smooth condition and this is where the fuel savings are achieved.

    Many of our customers who have used this service have noticed a remarkable difference in their fuel efficiency after each cleaning. One Chief Engineer said that ‘you can clearly tell the difference in a ships’ performance after Hydrex has done its thing [propeller cleaning].”

    If a problem arises, no matter how big or small, it is important for you that it gets solved as quickly and as efficiently as possible. Solving problems is exactly what we do, so do not hesitate to contact us for advice on dealing with both unusual and typical situations.