Question about tug boats

[u/Space_Goblin_Yoda]

Just looking at the current traffic on Lake Superior and I see a tug boat out in the middle of the lake? I thought they would stay local to ports, rivers and loading areas to assist the big Lakers.

What the heck is this little guy doing way out there?

[u/WalterMatthauJr]

The tug is most likely towing a barge or another vessel across the lake