群组

Auxiliary ships
Icebreakers - These are ships maintaining navigation in winter by leading other vessels across ice tracks (and breaking ice-floes). Compared to common ships, icebreakers have a strong bow and different construction of the hull whose purpose is to make ice blocks lift up the vessel. The principle of operation is the following: the ship climbs up the thick ice and cracks it with its hull weight, this way clearing pathways for other ships to cross.




Icebreaker


拖船（tug boat ）


拖船的尺寸较小，但其功率大、强度高、稳性好、操作灵活，主要用于协助他船进行港内操纵，其外形如图所示。大功率拖船还可用于海上拖带。



Salvage tugs (or tugboats) - high-speed vessels with an approximate length of 60 meters, used for towing barges and damaged ships and taking them across narrow canals or fairways. Tugs can do fast and easy manoeuvers to front, back and aside. This feature makes tugboats good assistants to big ships which cannot manoeuver on their own in narrow places and need help.




Salvage tug


Push tugs - vessels used for pushing an assembly of barges; Push tugs have very high superstructures which allow to keep a watch on the vessels in front and way ahead.