Saturday, 24 October 2009

Post-Panamax Ore Carriers: special-purpose bauxite ore vessels

My Company has just taken delivery of the final vessel of a series of five Post-Panamax ore carriers, built at Namura Imari Shipyard. This post describes their construction from concept to delivery.

My Company operate two alumina refineries, and have an annual demand for about 14 million tonnes of bauxite to be delivered for processing. Bauxite is also exported and sold in the international commodity markets, predominantly China.

The initial feasibility study called for a shallow draft bulk carrier which could be discharged at a Panamax berth within the typical gantry outreach. Post-Panamax coal carriers were identified as meeting the dimensions for the load and discharge ports, but were too wide to reach the outboard side using Panamax-outreach gantries. Working with Namura's initial design team, the high-cubic capacity coal carrier hull cross-section was modified for the heavy bauxite ore. The resulting design provided self-trimming holds which brought the ore within reach of Panamax-outreach gantries in an Capesize bulk carrier beam.

The vessel are operating within a sensitive marine environment, and load about 83,000 metric tonnes on 12.2 metres draft - about 40% more than a standard Panamax bulk carrier.

The contact was placed for the five ships, and the first vessel was delivered in 2007, with deliveries spaced about every 6 months until 2009.

I attended the sea trials of the second ship as Owners Representative, off the south-west coast of Japan in late summer 2008. The third ship was under construction in block assembly as we prepared for the trials.

This photo of the No.4 Hold shows the shedder plates which self-trim the ore into the small tank-top.

The Japanese Yard crew took her off the berth - we joined her at anchor to witness the Deadweight Calculation - and then sailed that afternoon for the open water for speed trials. While we were anchored, the ship's freefall lifeboat was launched as part of the barrage of acceptance tests.

Trials took two days, and the ship was accepted as attaining her guaranteed contract speed at the post-trial meeting as we berthed back at the Yard.

2009, and the final ship has just been delivered into service. The Owners Supervision Team has gone their separate ways after four years and five successfully deliveries. The next project is three 250,000 DWT Ore Carriers, commencing construction in 2011.

The Antipodean Mariner
24th October 2009

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