ALL SECURE
The ship is alongside and the lines are being run ashore one after other to make her fast. The number and placement of these lines varies with the location and construction of the pier, the type and size of the ship, and the weather and current condition that are expected.
The tidal current gets on the inshore side of the hull at the bow or quarter, an eddy current develops to further increase the strain on the lines, and the ship moves ahead or astern into the current. The ship rides outward and ahead on the lines, pivoting on them while the lines at the opposite end of the ship pull her in so she begins surging up and down the pier. Surging occurs because there is a greater strain on the upstream lines than on those leading downstream, and causes shock loading that parts lines.
Breast lines, the lines that are most effective in keeping the ship alongside, are overlooked although they should be doubled up like any others. If there are sufficient breast lines to keep the ship alongside, the strain on the lines leading forward and aft remains equal and the ship does not begin surging.
The surging is aggravated by passing ships whose hydrodynamic forces move the berthed vessel first away from and then toward the moving vessel, while also pulling the docked ship off the wharf. A pressure wave moves ahead of the approaching ship, and there is a decrease in pressure between the two ships due to the flow of water as they pass. It is especially important that the ship be kept hard alongside, with sufficient breast lines run and all lines up tight, at berths exposed to passing ship traffic.
Remember to call the ship that is approaching at excessive speed on the VHF radio and tell her to slow down. No longer is it necessary to stand by and watch a catastrophe develop because you cannot communicate. Look over the side and make sure the ship is alongside, then go to the VHF radio and tell the passing ship to pass at minimum speed with the engine stopped to assure that your vessel is not pulled off the pier.
