Once again, in an attempt to introduce reason to a very simple concept, like a sesame street series we will use similar concepts, just on a different scale.
When a car breaks down and requires a tow truck the local tow company comes with a truck of comparable size. When a highway rig breaks down a much larger tow truck is required. These are not always readily available in smaller communities, therefore the truck must sit and wait for a large tow truck to arrive, sometimes from long distances. In the picture above, a large 200 ton mine haul truck requires an equally sized large tow truck.
Although a smaller vehicle can tow a bigger vehicle on level ground with no turns, trouble always occurs when the combination needs to turn or stop. The smaller vehicle is always pushed out of control by the larger one being towed. Climbing hills or stopping on a down grade is all but impossible with a unit smaller than the rescued vehicle.
If an oil tanker becomes disabled no tug boat can maintain control of a vessel larger than the tug itself unless the conditions are ideal. Like the car/truck analogy the tanker must be in calm waters and barely moving. Any thrust in any direction by any force, tides, currents, winds, waves, momentum, any force will rule the tug as useless as a Mazda sedan attempting to control a fully loaded ‘B’ train chip truck on steep mountain highways.
As the picture above demonstrates, to control or to rescue a stricken tanker requires a rescue tanker of the same or greater size with enough power and ballast to completely control the vessel in all weather conditions.
Tug boats and pilot vessels could be compared to a traffic officer standing in the middle of a busy intersection directing traffic. As long as everything functions well and all obey the directions traffic flows smoothly. As soon as someone disobeys the signals accidents occur. And like a tug in the open ocean, if a vessel is on course to run over the traffic officer, there is nothing he or she could do to stop it.
Rather than accepting the idiotic proposal by Enbridge to have tugs tethered to tankers in Douglas Channel through to Hecate Strait we should be demanding full powered equal sized tow/tractor vessels attached until the vessel reaches open water. With five of these tow tankers stationed in the region one would be available for each incoming and out going vessel with one on standby for emergency rescue demands.
Unlike a truck disabled on a highway, floating/drifting tankers cannot wait for days for help to arrive. In hours they could be breaking up on a pristine shoreline somewhere.
Considering the extreme hazards presented by the product the proposed VLCC tankers will carry this is one logical approach to consider. Tug boats are for guidance only, and as has been so clearly demonstrated with the Shell rig grounding
, their purpose can not be considered effective for rescue or prevention of grounding and break-up.
And as was demonstrated this past November in Prince Rupert with the grounding of the Hanjin Geneva
, pilots on board do not control the ship nor are the captains of the vessel required to follow their instructions.
The picture below demonstrates the purpose of tug boats, to guide an almost stationary vessel into port, nothing more. Only the gullible would accept the proposal by Enbridge as reasonable.