If nothing else, offshore oil and gas production platforms can be useful waypoints but there's a good chance you could be scaring the pants off the folk on the rig and its standby vessel and playing havoc with production. Russell Robertson of Step Change In Safety explained it thusly: "The problem from the rig / installation side is that at around 20 NM, the vessel which is probably using the unit as a convenient way point becomes, to all intents and purposes, an errant vessel and potential threat because it is on a collision course with the unit. "The fact that, at around 5 -7 nm, the vessel will change course and go off to ruin someone else's day cannot be assumed by the rig and standby vessel. I just feel that the marine staff on the vessel need to be aware of the disruption that happens on a drilling rig or production unit when this situation occurs." Despite the resultant havoc, these incidents rarely get officially logged because the vessel doesn't enter the 500 metre zone around the rig or drill ship. Still, there are enough casses of ships clobbering platforms that there's no room for complacency. So, give a thought to the folk on the rig and help them keep their pants on.