315,ship hull resistance
the hull （below boottopping）smoothness should be considered in ship energy consumption aspect,the corrosion of sea water is the main cause of the hull roughness,and frequent grinding and painting can also cause the hull smoothness failing and sea animalcules inhabitting around the under water part of ship hull easily,for optimizing the energy consumption,it is necessary to maintain the ship hull regularly and improve the painting processes to keep the hull smoothness,
according to the speed changes under the same sea conditions,make estimations about the corrosion and sea animalcule absorption conditions,and confirm them during cargo handling in port ,
according to the inspection result,ship（crew）can take the mooring opportunity to clear the underwater sea animalcule pollutants or grinding the hull for reducing sailing resistance,
uusually ,the hull is more smooth,the fuel efficiency is higher,
·all the procedures of maintenance and pocess should be listed in ISM maintenance working plan,
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