Monitoring of hull condition of ships

In this thesis five bulk ships from Kristian Gerhard Jebsen Skipsrederi AS has been monitored over time in order to discover the increase in resistance due to fouling on the hull and propeller. Each ship has reported weather and ship data twice a month. These reports have been used to discover the resistance due to fouling by correcting all other added resistances from each measurement in the given time period. When all other resistance types are corrected for, each measurement is as if the ship travelled in calm weather. Then these results can be compared. The resistance types that are corrected for in this thesis are: Added resistance in wavesAdded resistance in windAdded resistance due to steeringSpeed loss due to shallow water When each measurement has been corrected for these resistance types, they are corrected to a reference speed and draft to be able to compare the results properly. In addition, the extent of the added resistance due to yaw angle because of lift forces from the rudder has been investigated and found to be neglectable. It has been found that the increase in resistance due to fouling is relatively linear the first two-three years. After three years the increase in resistance gets exponential