APPLIED oceanography specialist, Tidetech, has released the results of simulations of its tidal optimisation system on coastal shipping routes, showing significant time savings on optimised voyages, according to the magazine, Digital Ship.

The company said that, in simulations developed for transits through the English Channel, a time difference of 12.8 per cent was shown between 'best case' and 'worst case' passage times when using optimal tide and current based on an 8,000-TEU container ship steaming at 21 knots. Tidetech notes that this is the approximate equivalent of US$9,400 of bunker costs saved on one journey.

Speed optimisation using accurate tidal stream data differs from weather and route optimisation in that it is about choosing the best time to transit a passage where a choice of route is limited or restricted (channel transits, controlled shipping lanes, ferry routes, etc).

With route restrictions and the presence of tides, efficiency is found in timing the journey relative to current/tide and leaving/arriving at the right time to take advantage of the best current and optimising speed to maximise the positive effects of the current.

Using the English Channel as an example, timing a vessel's arrival at the entrance to the channel correctly means that the ship can make the most efficient passage through the Channel by going with the optimal flow of water.

Tidetech's English Channel simulation showed that the best case transit at slow steaming speeds of 19 knots is 32 minutes faster than the worst case transit at 21 knots. Based on an 8,000-TEU container vessel, the company said that this is a difference of approximately 35.8 tons of bunkerage, or approximately $25,000.

"It's clear that no stone is being left unturned in the drive to improve efficiency of shipping the influence of tide and current is an obvious challenge to address," said Tidetech managing director, Penny Haire.

"The reason it's not been addressed before is that the information just hasn't been available - now it is and can make a significant difference if applied correctly."

"Our accurate, high-resolution global tidal data can be integrated into bridge systems allowing ships to make use of advantageous current, steam at more efficient speeds and minimise fuel used and time spent in transit."