For example permits could be issued to travel through locks at specified times and those permits could be traded among towboat captains .

比如，可以通过许可证的发放将船闸通行 限定在指定时间内，而且许可证 也可以在 拖船船长之间进行交易。

Diagnosis for faults of rotary propulsion apparatus operating system in towboat and general methods to deal with it

拖轮 全回转式推进装置操纵系统故障判断和处理的一般方法

Test of the optimum routing and service for the operation of ocean towboat in winter season

冬季远洋 拖轮作业的最佳航线服务试验