(1) The proposal is contradiction to other Internal Standard (ISO4867, ISO4868, ISO10055 etc.).

(2) Since ISO6954 have been published in view of habitability, it is not necessary to prepare the new standard for the superstructure.

(3) Stress caused by the structural vibration strongly depends on the size, shape and details of the structure. It is possible that stress level exceeds allowable one even if the maximum vibration amplitude is within the vibration limit. Furthermore, fatigue life also depends on the type of connections (welded, bolted, etc.). From those reasons, the effect of global structural vibration on ship structures and machines shall be evaluated individually.

(1) The proposal states "vibration data should be recorded from half-power to full power to evaluate vibration level of resonance. But it is essential for endurance of structure to evaluate the vibration response with machinery running under normal condition. Therefore, it is not necessary to be recorded from half-power to full power.

(1) In general, S-N curve, inclusive of the level of endurance limit, is strongly dependent on materials, type of connections, structural details and so on. Therefore it is not adequate to draw the criteria from single S-N curve.

(2) The proposal states "a 10mm/s rms amplitude measured at the stem would indicate a mechanical problem (Annex B)", only from the investigation of propeller unbalance, in spite of the fact that there are various sources of ship vibration other than propeller forces.

(3) The response for unit loads, that composes a basis of the proposed criteria, is estimated from the investigation on two ships (Annex B). However, it is known that the response largely fluctuates depending on variation of mode shapes, damping and so on. The data, thus, seem to be too little to establish criteria.

(4) The criteria shown in page 6 are determined only in view of machinery reliability and maintainability. So the criteria are not applicable to evaluate endurance of structure itself.

(5) The vibration criteria of the machinery are published individually. At the design stage to evaluate the machinery vibration, we consider the structure including the mounting. Therefore, it is unreasonable to evaluate the hull structure only.