Norsk Marinteknisk Forskningsinstitutt

Trondheim 20141211

A-LEX – Work meeting

Technology challenges

Tor Einar Berg Ørjan Selvik

Presentation abstract

• Technology challenges related to Arctic shipping could be grouped in these topics:

− Navigation and communication

− Traffic surveillance

− Escape, evacuation and rescue

− Vessel and offshore unit design and necessary modifications for operations in Arctic waters

• This presentation focus on handling of drifting vessels to prevent total loss or grounding

− New methods for prediction of path of drifting vessel are needed

− More knowledge on vessel flow around a drifting vessel is needed to understan how to position the rescue tug when reparing an emergency towing line

− Installation of emergency towing gear on vessels operating in Arctic waters could ease the work to set up a robust emergency towing system

Technology challenges

•Traffic surveillance

•Path prediction of drifting vessel

•Operation of towing vessel close to a drifting vessel

•Towing point on drifting vessel

•Towing force monitoring Kamaro towing

Traffic surveillance

• AISSAT

− One dot = 1 ship day

• NORVTS

− Surveillance of ship traffic, identify nonconformities

− Prevent situations by being in contact with ships and offshore units

− Act and alarm if needed

− Administer the governmental towing resources

AISSAT-1 data showing vessels in Arctic waters

Path prediction of drifting body

Drifting body test performed by dropping dummy from KV Andenes – as part of NTNU thesis by Øyvind Sjåstad Bech

A-LEX – calculation of drifting path of disabled vessel

• Cargo vessel designed by Rolls-Royce Marine

• LOA: 120m

• Breadth: 20.8m

• Ice class None

Bilde: http://www.rolls-royce.com

Case parameters – environmental conditions Case: Ship with engine black-out at the Kara Gate

• Waves

• Hs 5.0m

• Tp 11.0 s

• Direction 90°

• Pierson-Moskowitz

• Wind

• Speed 20 m/s

• Direction 300°

• Current

• Speed 0.25 m/s

• Direction 120°

Result – waves, wind and current Drift speed ~4kn

-6000

-5000

-4000

-3000

-2000

-1000

0

1000

-1000 0 1000 2000 3000 4000 5000

Nort

h [

m]

East [m]

DRIFTING TEST

ALEX2 Waves, wind and current

Ship symbols are shown every 120 seconds.

10

20

30

40

50

-1000 0 1000 2000 3000 4000

Headin

g [

deg]

Time from start of manoeuvre [sec]

Heading

ALEX2 Waves, wind and current

ALEX2 Waves, wind and current: Heading

Operation of towing vessel close to a drifting vessel • In a number of cases tugs have been

unable to establish an emergency towing line due to harsh weather conditions

• In Tromsø workshop the captain of a Norwegian Coast Guard vessel asked for more knowledge on water motions along a drifting vessel

• Towing vessel manoeuvrability in harsh weather – reduce effect of thrusters due to ventilation

KV Harstad – Kamaro towing operation

Towing point on drifting vessel • Only tankers about 20000 dwt are

required to have a strong point for emergency towing

• Emergency towing systems needed for certain types of vessels

• Where to make an emergency towing connection on bulk carriers, passenger or fishing vessels?

• Operational problems on steel vessels with aluminium superstructure

Smitt brackets work to 100/200/300/400te loadings and suit chain sizes up to 96mm. The bracket is acritical part of an Emergency Towing System

Towing force monitoring

• Tension monitoring for towing wire needed

− Initial system on KV Harstad was removed prior to the Kamaro towing

− New system will be installed on KV Harstad in the near future

• Aiviq had a tension monitoring on their towing winch under towing of Kulluk

− Overload alarms were misunderstood by 3rd Mate on watch

Rescue operation – prior to Kulluk grounding

Tow force monitoring – on Aiviq during Kulluk towing

IMO mandatory emergency towing system

• Mandatory towing arrangements Since 1 January 1996 all new tankers of 20,000 dwt and above have had to be fitted with an emergency towing arrangement fitted at either end of the ship. Existing ships had to be fitted with such an arrangement not later than 1 January 1999.

• What about other types of vessels?

Emergency Towing System

Rapp Bomek has developed a safe, economical

emergency towing system that complies with IMO rules

for tankers above 20 000 dwt. The light compact system

is stowed on deck in a watertight compartment fixed to

the deck, with no wires, chains or ropes to get in the

way during normal operation.

The system has a relatively low weight and is as good

as maintenance free and is quick and easy to use, not

requiring any firing, hauling or fastening to the damaged

ship.

No reference to emergency towing is found in the Polar Code