Tug boats are built in difference sizes for different purposes. Salvage tug boats are the bigger one with modern communication equipments and facilities. They used to wait in ports in fully alert condition where always one person on watch for listing communication for any possible distress calls from any where in the seas or port area.
If they got any distress call, the tug moves on full speed to get to that ship in trouble as the first tug may get the offer for the salvage operation where big money involved. Some time towing a big ship may take nearly two months to reach a port. Normally they tow ships which are going to be scraped for metal while the ship is not moveable by ship’s engine.
The salary of the tug boat crew is not great like merchant ship but they have plenty of spare time for entailment like fishing, watching videos, talking in VHF with passing crew members.
Tug boats which are towing the bunker barges.
Here crew members has to work non stop as at any time any ship may come for bunkering purpose. Some time they have to work more than 16 hours. Some time for days there may be no work too. In some countries shore leave to this tug boat people are not allowed.
There are many seaman lived their entire contract period with out seeing the land. Sending money to their home will be done by the agents and personal provisions and mails too brought by the agents.
Timber log towing barges, supply tugs and many kind of them are available. For unknown reason many tug boats went in to the seas while towing big size barges with heavy load.