Analysis of Hull Coating Renewal in Ship Repairing

Abstract

Hull coating (external blasting and painting) renewal (repair) is a part of routine ship maintenance. It is carried out only when the ship is in a dock (graving dock, floating dock, or slipway). For a regular maintenance schedule, the scope of hull coating repairing works dictates the duration of stay of a ship in the dock. It is very vital therefore to estimate the scope of work for hull coating before docking. As soon as the ship is docked, a joint hull inspection by representatives of the owner, drydock, and coatings supplier accurately determines the hull coatings scope of work. Most of the time, the inspection result does not match with the preplanned dock operation schedule. Hence, the overall dock operation schedule gets affected due to delay or early undocking of a ship. Hull coating repair and related information for 149 cargo ships were collected from a single shipyard. It was analyzed and presented in both tabular and graphical forms to show the relationship between the scope of work and the age, size, and type of ships. The physical size of a ship has a great influence on the hull blasting and painting repairing works irrespective of design parameters and types of the ship. Using ship dimensions, actual surface area, and other factors, a method of estimating the hull coating scope is proposed. In this article, the authors have made an attempt to identify the independent variables that influence the scope of work (dependent variable), and suggested the possible interrelationships between the dependent and independent variables, which appeared to be linear.

Ship Painting Process Design Based on IDBSACN-RF

“…To analyze the effect of the maximum depth of decision tree max_depth on the classification results, set the minimum sample required for internal node re-division as 2, the minimum sample of leaf nodes as 1, the number of decision trees n_estimators = 70, the maximum depth of decision tree max_depth ∈ [1,10]. The results of the maximum depth of decision tree optimization are shown in Figure 5.…”

“…When the decision tree depth is varied in the range of [4,10], the accuracy fluctuates in the range of 0.001, indicating that the algorithm has good robustness. To analyze the effect of the maximum depth of decision tree max_ depth on the classification results, set the minimum sample required for internal node re-division as 2, the minimum sample of leaf nodes as 1, the number of decision trees = _ 7 0 n estimators , the maximum depth of decision tree ∈ max_ [1,10]…”

“…DBSCAN defines a "cluster" as the largest set of density-connected samples derived from a density-reachable relation. If x is the core object, the set consisting of all samples is density-reachable from x is shown in Equation (1).…”

“…Ship painting is one of the three pillars of modern shipbuilding and is used throughout ship construction [1]. The design of the ship painting process mainly includes the selection of coating matching, the development of surface treatment level, the development of secondary descaling grade and the design of the process routine [2].…”

Coating Matching Recommendation Based on Improved Fuzzy Comprehensive Evaluation and Collaborative Filtering Algorithm

“…Ship painting is one of the three pillars of modern shipbuilding processes and is used throughout the shipbuilding process [1,2]. As the anti-fouling barrier of the hull, the coating is essential for the structural integrity, hydrodynamic performance and service life of the ship [3].…”