UT 790 CD Deepwater anchor-handler

Stability with efficiency

Normally a larger beam for greater stability would imply extra hull resistance, but the UT 790 benefits from a new 23m form that has lower resistance than traditional 20 and 22m designs and combines a wave piercing bow that pierces through the water rather than riding on top of the waves.

This allows the vessel to run continuously at service speeds regardless of sea-state and eliminates slamming. At speeds of 14 knots and violent storm conditions (waves higher than 9m), tank tests show no water above forecastle deck level. In extreme wave heights, water will be visible at the forecastle long before the situation gets critical, allowing power to be reduced and the maintaining of generous safety margins.

The UT 790 CD re-thinks anchor handler layout, moving the engines further aft and locating the secondary winches low down, where the engine room would traditionally be, to help improve stability and free-up space.

The UT 790 CD has the same fibre and rope capacity operating with four secondary winches as a traditional anchor-handler has with six. The vessel has the power and capacity to handle cable, chain and rope down to 2000 metres, and fibre rope down to 3000 metres.

Another notable feature is the extra buoyancy in the cargo railings, providing further stability and safety in case of extreme heeling levels.
 
Locating the engine room astern also reduces engine noise and permits shorter exhaust ducting which includes a Mecmar wet exhaust system, with cooled exhaust leaving the ship at sea level.

As there are no exhaust casings the enhanced 360-degree view from the bridge significantly improves safety.

Cleaner and safer operation 

An innovative triple screw hybrid mechanical/electrical propulsion system combines a central controllable pitch propeller (CPP) with two Azipull thrusters with nozzles for the best in propulsive efficiency. The system allows the UT790 CD to use the minimum fuel to do the job in its various operating modes, with maximum flexibility.

Modes range from sailing in diesel-electric mode at 10 knots and sailing in mechanical mode using only one engine at 14 knots, to combined systems for maximum pull and an efficient system with a high level of redundancy for dynamic positioning. Click to view main modes.

Rolls-Royce Bergen engines meet Clean Design class rules without further exhaust cleanup. Catalytic converters can be fitted to the generator sets, giving ninety per cent NOx reduction.
 
With its special redundant drive solution, the forward azimuth thruster can be powered by two independent switchboards, enabling the UT 790 to achieve the same DP2 capability with three thrusters than conventional solutions with four.
 
The UT 790 CD comes with a full Rolls-Royce Safer Deck Operations (SDO) system, including anchor-handling cranes, chain wheel changer and torpedo anchor-handling system. SDO introduced four years ago is seen as standard equipment on high-end anchor handlers. It improves safety by keeping the crew away from danger zones, while maintaining operational flexibility and efficiency.