2. Towage Service.—
This is rendered by the tug to the tow. Tugs are usually specially built and equipped for the business and supply a very important aid to commerce and navigation. The service is generally by contract or informal agreement and includes both the short work in shifting vessels in port and the long voyage and season contracts along the coast and in the canals and Great Lakes. It may be performed in various ways. Sometimes the tug is lashed to the tow and supplies motive power only and sometimes she pulls several vessels behind her upon hawsers from each to the other of great length. The legal relations, however, are usually the same.
The tug should be supplied with hawsers of sufficient strength to hold the tow in any weather which may be reasonably anticipated, unless the tow itself supplies them. Where the tug is given full control, it should arrange the order of towage and the distances apart. It should also arrange, by an understood code of signals, for shortening, lengthening, or casting off the lines, as exigencies of navigation may require. Vessels of heavy draft should be placed behind those of lighter draft. The speed of the tug should be such as is reasonably safe for the condition of the tow and sudden jerks and turns must be avoided. Disaster does not necessarily absolve the contract of towage. On the contrary, it is quite settled that it is the duty of the tug to continue to do all in its power to get its tow out of situations of difficulty and danger, short, of course, of sacrificing its own safety. It is not relieved from its obligation because unexpected difficulties occur and may not lightly abandon the tow to its fate. Extraordinary services under a towage contract may secure a salvage reward, but too great haste in abandoning it will impose a corresponding liability.