Section 2 Construction under Main Engines

201. Construction under Main Engines

1. Girders upon which main engines are installed are to be of sufficient length as to the engine foun- dations, and the form is not to have any abrupt changes or discontinuities.

2. Girders are to be effectively supported by frames and brackets in order to maintain sufficient lateral strength and rigidity.

3. Where engines which have large unbalanced inertia force or large unbalanced moment of inertia are installed, the strength and rigidity of the girders supporting those engines are to be made especially sufficient.

4. Fixing bolts for main engines are to be have adequate shank length in order to lower their rigidity and effective means to avoid loosening.

5. Where engines which are subjected to large exciting force due to piston side thrust are installed, the connections of girders with frames and brackets are to be made rigid, and resonance is to be avoided against the vibration in the horizontal direction.

6. Webs of girders may be constructed with timbers interposed between FRP in order to increase the rigidity against compression or bending. In this case, the connections of FRP with timbers and of timbers with bottom shell laminates are to be effectively bonded.

7. The bonded connections of girders with bottom shell laminates, frames and brackets, as well as their mutual connections are to be T-type joints using ample roving cloths and the width of joints is to be sufficient. In this case, the direction of roving cloth fibres is not, as a rule, to be oblique to the connecting line.