To launch a ship or a boat means to put it into water, often for the first time after it has been built.
使 (新船等) 下水 There was no time to launch the lifeboats because the ferry capsized with such alarming speed. 因为渡船倾斜的速度如此之快,根本没有时间把救生艇放下水。
his morning's launch of the space shuttle Columbia has been delayed.
定于今天上午哥伦比亚号航天飞机的发射已经被推迟了。
launch a rocket / missile / satellite