3.5 Classical techniques for assessment of hull structures
At present, assessment of hull structures relys on close up survey and ultrasonic thickness measurement. Modern and more reliable techniques to assess a whole ship easily are earnestly desired.
3.6 Inadequate sensibility for seriousness of defects in hull structures
Hull structures of a ship bear loads from cargos, ballast water and waves not constantly but variably and at random. And, a structure seldom encounters the severest condition as the basis of its design.
Engineers in charge of repairing have experienced many ships who have been satisfactorily operated in spite of marked defects in her structures. But, the ship owes such satisfactory operation most probably to luck that she has not encountered the critical sea condition estimated at the time of her design. As it is very rare for an engineer in charge of repairing to see structural damages occurring under the critical condition, there seem to be many enginers who have not seen such damages.
An engineer in charge of repairing tends to establish his own theories for technical dudgement according to his experiences. Accordingly, there are some possibilities that assessment or repairs of ageing hull structures are done with such inappropriate theories.
4. Suggestions to solve the problems
All problems described in Chapter 3 come from conservative systems and customs in shiprepairing. With extension of the traditional movements, epochmaking advancement of technology for assessment, repairing and maintenance of ships cannot be realized.
In the first place, in order to solve the problems, the speaker is proposing technical exchange between shiprepair yards and united efforts of all concerned to establish advanced technology of shiprepairing. In Japan, there is a growing tendency to realize the proposal. Technology for shiprepairing may hopefully hold a position as a field of technologies for naval architecture in the Society of Naval Architects of Japan.
After the movement makes steady headway, problems described in Chapter 3 will be solved positively.
