Odfjell brings new scale to chemical trades
‘Bow Pioneer’, delivered this year to Odfjell Tankers of Norway by DSME in South Korea, is the largest type 2 chemical tanker afloat, and is described here by David Tinsley.
Brought into commission in mid 2013 by Odfjell Tankers, one of the leading lights in the chemical trades, the Bow Pioneer ranks as the world’s largest, fully IMO Type 2 chemical tanker by virtue of a cargo volume of just over 86,000m.
Bow Pioneer had been ordered from Daewoo Shipbuilding & Marine Engineering in July 2010 at a price of about US$65 million, substantially less than would have been entailed if the owner had decided to go ahead with a contract some years earlier when design planning had been put in hand.
The exceptional size of the chemical/product carrier is testament to Odfjell’s perception of opportunities for scale, particularly as regards the export traffic from the Middle East, where a major expansion of refinery capacity is under way. The project is also illustrative of recent years’ investment orientation by chemtanker fleet operators towards coated tank vessel designs rather than stainless ships,
At the time of the contract, Odfjell had described the new class, with its design deadweight of 75,000dwt, as a “quantum leap” for the business, offering reduced fuel consumption and emissions per tonne mile in combination with cargo carrying versatility. At the scantling draught, the deadweight is still more impressive at 81,200dwt. With coated tanks throughout, the highly compartmentalised design affords scope across the range of Type 2 and Type 3 chemical categories augmented by the extra flexibility to load oil products. On long voyages, the vessel will benefit from substantial economies of scale.
At the time of writing, a second such tanker was nearing completion at Daewoo’s Okpo yard to the account of National Chemical Carriers (NCC) of Saudi Arabia, with completion anticipated for November. Although the joint NCC/Odfjell pool of coated chemtankers in the 40,000-45,000dwt range was dissolved in June 2013, cooperation between the two organisations has been retained for the two new 75,000dwt vessels, which are being placed under NCC’s commercial management.
The cargo section of Bow Pioneer is subdivided by transverse, corrugated bulkheads incorporating lower stools, and by two longitudinal, corrugated bulkheads to create 10 sets of tanks forming 31 separate cargo tanks. Inorganic zinc silicate coating has been applied to all the tanks, with stainless steel having been used in the cargo lines. The cargo handling layout culminates in a total of 31 individual tank connections at the amidships manifold.
The arrangements cater to the full range of Type 2 and 3 cargoes including methanol, vegetable oils, mono ethylene glycol (MEG), ethylene dichloride (EDC), methyl tertiary-butyl ether (MTBE), xylene, toluene and cyclohexane, as well as refined petroleum products.
In accordance with tank filling restrictions governing Type 2 products, all the cargo spaces are of under-3,000m³ capacity. With their flush internal surfaces, the tanks’ strength members and stiffeners are externally-located, as so clearly evident on the weatherdeck. A raised catwalk has been fitted along the centreline, providing safe access from the front of the superstructure to the manifold platform area, and beyond to the forecastle with its mooring and anchoring gear.
Hydraulically-driven Framo cargo pumps are fitted throughout, whereby 29 deliver a throughput rate of 600m3/h and two are rated for 300m3/h. For oil cargoes, each tank is equipped with stainless steel heating coils fed with steam produced by the Alfa Laval Aalborg boiler plant. An Alfsen & Gunderson drying and dehumidifier system of 15,500m³/h capacity ensures the tanks are moisture-free after cleaning by the multiple, fixed Scanjet machines.
Bow Pioneer is installed with a five-cylinder MAN Diesel & Turbo S60MC-C8 main engine, produced under licence by Hyundai Heavy Industries. This has been specified with a maximum rating of 10,870kW at 103.7rpm and is direct-coupled to a fixed-pitch propeller. The arrangements allow the tanker to make 14 knots at the design draught of 13.2m, on an even keel, at the 85% maximum continuous output of 9,240kW. The prime mover’s five cylinders and power level in relation to the ship’s size would appear rather modest, but the specification is in line with the drive for economical performance and economical speed, which is about two knots less than would have been sought some years ago.
The four auxiliaries are laid out abreast of each other on a platform in the aft section of the main machinery space, and provide an important new reference for Hyundai’s HiMSEN brand. Two of the aggregates are based on seven-cylinder models of the HiMSEN H21/32 engine, and the other two employ five-cylinder versions.
Applied to the ship’s seawater cooling system, the Desmi OptiSave control system and variable speed drives optimises pump speed to precise, required demand, improving energy efficiency to an extent that is expected to yield average annual savings of some 120t of fuel oil.
Bow Pioneer is a name of historical significance for both Odfjell and Daewoo. The original Bow Pioneer was the first vessel ever to have been built by Daewoo, having led a pair of 23,000dwt chemtankers delivered to Odfjell’s predecessor A/S Storli in 1982.
Odfjell currently has four further IMO Type 2 vessels under construction in South Korea. Derived from a medium-range (MR) tanker hull design, the new class of 46,000dwt ‘eco’-type chemical/product carriers has been assigned to Hyundai Mipo Dockyard. Deliveries are due over the period between January and July 2014.
The hull, propeller and derated main engine have been optimised to a lower speed range, with a service speed of 14 knots. The normal continuous rating of the engine will be just 6,209kW at 94.1rpm. Including an anticipated 5% benefit conferred by a Mewis duct, it is claimed that the ‘eco design’ overall will offer a fuel saving of 20% relative to the average consumption of MR tankers as a whole.
PRINCIPAL PARTICULARS--chemical/oil tanker Bow Pioneer
Length overall: 227.9m
Length bp: 219.0m
Draught, design: 13.2m
Deadweight, design: 75,000dwt
Draught, scantling: 14.0m
Deadweight, scantling: 81,200dwt
Gross tonnage: 45,452gt
Cargo capacity: 86,280m³
Cargo tanks: 31
Main engine power: 10,870kW
Service speed at design draught: 14 knots
Class: Det Norske Veritas
Class notations: 1A1, CSR, Tanker for Chemicals and Oil Products, ESP, E0, NAUT-OC, BIS, ETC, TMON
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