Thrust & Bollard Pull

What you see here is our tow wire under (considerable) tension connected to the Hermod. The force a tug is pulling with is called Bollard Pull and for both the Husky and Retriever this happens to be 160 metric tons. Of course this force is supplied by our main engines and transferred via our propellers to the tow wire. Even after more than 30 years service on ocean going tugs it is still onconceivable for me that propellers (even big ones) are able to get so much grip on a fluid medium like water to produce such an enormous force.