Once a mooring line is attached to a bollard, it is pulled tight. His teammate Barrichello hit a trackside bollard entering the Bus Stop chicane on lap 17. A tugboat is typically rated by its engine's power output and its overall bollard pull. The bollard pull of the vessel is 158 tonnes. A bell bollard is a style of bollard designed to deflect vehicle tires. Normal pressure comes into being between the rope and bollard, but no friction occurs yet. General styles of racks include the Inverted U, Serpentine, Bollard, Grid, and Decorative. A bollard is a sturdy, short, vertical post. Thus the choice of bollard styles must apply to the NFPA's Code 1710. In an ice bollard ice is chipped away to create a teardrop shaped "bollard". May crashed the caravan into a bollard. Bollard pull can increase up to 30% with ducts. In the final situation the bollard exercises a friction force. Alex Bollard and Lex Vandyke have also covered the song. See Figure 2 for an illustration of error influences in a practical bollard pull trial.