Feature 2 | SUPPORT VESSELS

Simek delivers North Sea PSV to Simon Møkster

Norwegian shipyard Simek AS has delivered a platform supply, rescue and standby vessel to North Sea Safety KS for ship operator Simon Møkster Rederi AS. Here we take a closer look at the design and technology of Stril Mermaid.

T

he vessel, Stril Mermaid, is of Havyard Maritime AS design type 832 CD RS. Tis design is specially

adapted to the job as a standby safety vessel in the North Sea. The contract for Stril Mermaid was

initially signed on 8 September 2008 and the vessel was delivered to the ship operator in April 2010. Te vessel was initially signed on a spot market contract but has since been signed up to a 5-year fixed contract with Marathon, BP and Exxon Mobil for the Alvheim field in the North Sea (with another 5 years option). According to Simek this is partly due to all of the extras that the owners have put into the vessel compared to a ‘standard’ platform supply vessel (PSV). Stril Mermaid is the second vessel to be

delivered to Simon Møkster Shipping AS from Simek, her sister vessel is Stril Mariner. Stril Mariner was delivered in October 2009 and is included in Significant Small Ships of 2009 publication. Stril Mermaid is a 78.6m loa vessel with

a beam of 17.6m and depth measurement to main deck of 7.70m. Her draught during summer is 6.54m and her deadweight is 3743tonnes. Two of the main generator engines

onboard Stril Mermaid have been upgraded; together with the replacement of one side thruster with a retractable azimuth thruster, such as that seen in Stril Mariner. Te vessel has been built according to the

highest class in Det Norske Veritas (DNV), with the following class notation: 1A1, E0, SF, Dk(), Hl(2,8), COMF-V(3), CLEAN DESIGN, NAUT-OSV, DYNPOS AUTR, Fi-Fi I, OILREC, LFL* for worldwide trading. In addition to the Norwegian Ship Control

rules, the vessel also complies with NOFO Standard for Oil Recovery Vessels of 2009. Te NOFO (Norwegian Clean Seas Association for Operating Companies) Standard is the requirement, set by Norwegian authorities and

26

classification societies, vessels have to meet to be part of the oil recovery fleet operating in case of oil spill in Norwegian waters. The vessel also complies with the

Norwegian Rescue Class Rules for taking onboard 300 persons in an emergency, together with NORSOK and NMEA standards/guidelines. The vessel is divided into watertight

compartments and is double hulled to comply with the Clean Design Class and SF for damage stability. Clean Design means that no fuel oil or any other liquids that are dangerous to the environment are in direct contact with the vessels shell. Between the sea and the harmful liquids there is a minimum of 760mm, containing sea or fresh water. Tis means that if a minor collision or grounding should occur, there will be no spill or danger to the environment. To avoid pollution to the air, the main

generators exhaust system has been fitted out with a selective catalytic reduction (SCR) exhaust gas cleaning system, cleaning the environmentally hazardous carbon monoxide, nitrogen oxide (NOX

)

and volatile organic compounds (VOC) in the exhaust with ammonia, and the nitrogen oxides of the exhaust gas become environmentally natural substances water (H2

O) and nitrogen (N2 NOX ), thus reducing the by approximately 90%. As the vessel is a diesel-electric vessel it

is fitted out with four generators producing electric power to the propulsion and other consumers onboard. By having several engines, you only use the number of engines necessary for the power needed at any time, therefore being more efficient. Aft is the propulsion room where two

Rolls-Royce Marine Ulstein Aquamaster US 205 CRP azimuth thrusters are driven by electric motors of up to 1500kW. Te motors are frequency controlled, controlling the revolutions of the motor from 0–1200rpm, again turning the propellers 0–197rpm.

Forward of the pump room on tank top

is the bulk room with the new Cargomaxx supplied dry bulk system. Te system is an integrated cargo system whereby all cargo tanks can carry dry or wet cargo. Te cargo tanks for the Cargomaxx system are made without the pressurised bulk tanks. The system is developed with the principle to combine liquid and dry cargo in the same tank. With liquid cargo, the tanks work as regular tanks. With dry cargo, the tanks are loaded from ashore with compressed air, which blows the cargo directly into the Cargomaxx tanks. When discharging the dry bulk, this is done by means of the Van Aalst VP (Vacuum – Pressure) type bulk handling system. Te dry bulk will be sucked by vacuum into a re-loader tank. Once a re-loader tank has been filled, the re-loader tank will be pressurised by means of compressed air. Aſter a pre-set pressure has been reached inside the re-loader tank, the pipeline will be opened and the dry bulk will be blown out. Te upper part of the bulk room is fitted

out with various cargo tanks. Forward of the bulk room, through a watertight sliding door, supplied by IMS together with the two other similar doors onboard, we enter the engine room with four off generator sets with Cummings engines, two of type KTA50DM, developing 1291kW, and two of type QSK60DMI, developing 1900kW each, connected to a Marelli generator supplied by Scandinavian Electric Systems AS. In the forward part of the engine room

are situated two electric-driven fire-fighting pumps for external fire fighting according to Fi-Fi I, each delivering 1723m3/h of seawater, of which 1200m3/h is to the two monitors installed on top of wheelhouse and the rest for fire protection by water curtain of the vessel itself. Forward of the engineroom is the

thruster room with one off-side and one retractable azimuth thrusters installed,

Offshore Marine Technology 2nd Quarter 2010 Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44