Fast Dead Slow Ahead

EUROPEAN tug owners and pilots today sounded an alert about dangers posed by ultra-large box ships.

it is wrong to consider a minimum speed of 9-11kt as ‘dead slow ahead’ when dealing with 10,000teu vessels.

http://www.safetyatsea.net/

Several of the new large container vessels have a very large main engine output. It seems that engine manufacturers, classification societies and ship owners have focused on economics for a sustained service speed.
Due to considerations of fuel economy and technical limitations the engine regimes are strictly computer controlled.
In reality these ships have a minimum speed ( dead slow ) in excess of 6 knots, even up to 10-11 knots.
Although pilots and tugboats serve almost any ship or structure taking into due consideration the manoeuvring characteristics and limitations we have received reports that indicate that high minimum speeds cause problems.
With a displacement of 80.000 – 100.000 ton navigation at 8-11 knots
• difficulties due to bank effect and interaction between vessels on canals and restricted fairways
• surging and danger to break lines when passing jetties EMPA Secretary General or terminals
• safe speed when approaching berths/locks.
• approach and making fast tugboats, especially at the bow.