Reducing pipe penetration costs in shipbuilding

Abstract

Western shipyards have to distinguish themselves by complex ships with short delivery times. This entails that in most cases the production already starts while the engineering has not even been finished. If the pipes and cables are not routed when the steel plate are cut by the CNC machine, the associated penetrations have to be cut manually during section building, which is very expensive.
The ideal situation is to know the location and size of all penetration before the plates are cut. However, this is not realistic in all cases and therefore a new engineering and production approach is devised. If the penetrations are not known on time, large openings are to be made which can later be filled with inserts, when all exact penetrations are known.
It is possible to just open a lot of large openings, or an estimation concerning optimal openings can be performed. In this research, several algorithms have been created to estimate an optimal opening for a certain penetration, and to check whether this penetration fits in the estimated opening. For the closing of the opening, several methods are described as well. An obvious choice is to close using a welded steel insert plate. A less obvious choice is the rather new product called NOFIRNO®. Both solutions have some advantages and disadvantages for different situations.
All the algorithms are validated by comparing the results to actual built vessels. With the accurateness of this validation, a business case has been performed for several opening methods, combined with several closing methods. The final conclusions and recommendations are not unambiguous for each situation.