船台是固定的地面支撑，下水支架仅用于下水时。后者在下水时与船体一起滑入水中。

Building berth is the fixed ground support and launching-cradle is only used while launching. The latter will be sliding together with the ship into the water.

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否则应把支架垫在主梁的下水平盖板靠近主梁两点变高处。

Otherwise, the bracket should be placed in the bottom of the main horizontal cover plate near the main beam two points to high.

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