Title: System-Based Ship Design of a Deep-Sea Mining Vessel

Author / Sponsor: Astrid V. Solheim, Brage R. Groven, Jan M. Røsbjørgen, Aron Wigdahl, Svein Aa. Aanondsen, Per Olaf Brett, Bjørn Egil Asbjørnslett / Norwegian University of Science and Technology (NTNU). Research funded by the NTNU Oceans program.

Date: Published Online September 2024; appears in Ship Technology Research 2025, Vol 72 No 2.

Report Length: 15 pages (pp 73-87).

BLUF: Applying System-Based Ship Design (SBSD), the authors lay out a 230 m nuclear-powered production vessel able to lift, dewater, store and trans-ship up to 0.8 million tons of ore each year from Norwegian Sea sulphide deposits. By budgeting space, weight and power for every task first, then shaping the hull around them, they show a practicable concept built largely from proven offshore-oil technology. Data gaps persist in hydrodynamics, radiation zoning and shuttle logistics, but none appear fatal at this early stage.

The mine site sits on the Norwegian Extended Continental Shelf between Svalbard and Jan Mayen. SBSD begins with three production goals, 300, 500 and 800 kt wet ore per year, which translate to base slurry flows of 354, 454 and 944 t h-1. A 15 percent design margin lifts the mid-case flow to 590 t h-1, keeping annual availability near 74 percent. SBSD next explodes the mission into functional blocks (slurry lift, dewatering, storage, ship-to-ship transfer, hotel, power) and sizes each block with supplier data and comparable ships before any lines are drawn.

The “wrapper” that encloses the blocks is 230.7 m long, draws 16.27 m and carries an unusually full block coefficient of 0.867 to house bulky plant. Lightweight is 27,709 t; deadweight 75,416 t; loaded displacement 103,125 t. Beam is tentatively fixed at 32 m by reference to ultra-deep drillships pending tow-tank work. These numbers give a length-to-beam ratio of 7:1, slender enough for transit yet stout in mid-body for process equipment.

Ore moves into multiple raised wing tanks so the ship is not over-stiff; metacentric height stays between 2.3 m (ballast) and 3.0 m (full load). Forty-seven ballast tanks holding 19,229 m³ let operators trim both heel and longitudinal center-of-gravity in changing sea states, while the high block coefficient gives generous reserve buoyancy for future upgrades.

A 20 m internal turret moonpool secures the riser buoy. The vessel can disconnect in significant wave heights above 5.6 m, a value set by turret bearing limits rather than hull strength. Disconnect capability preserves the expensive riser if winter storms exceed design seakeeping margins.

Incoming slurry passes double vibrating screens to strip coarse debris, hydrocyclones for density cut, then a high-g centrifuge train. Only particles smaller than 8 µm accompany the return water to depth, limiting surface plumes. Three conveyor belts (upper, mid and lower) share ore evenly into raised storage tanks and later feed it aft to the transfer station. Task-level mass-flow analysis shows 57-154 t h-1 dry ore through the plant across the three cases, matching the slurry inputs.

When holds are full, locks open under the tanks and conveyors carry ore aft to a 76 m heave-compensated boom. The boom maintains 40 m side clearance to a bulk carrier and pumps 10,000 t h-1, emptying the vessel in roughly 8.5 hours while tolerating up to 5 m significant wave height. Angle adjustment and draft compensation keep the discharge hopper aligned as load-out lightens the ship.

Operating profiles peak at 30.7 MW; designers install 35 MW to allow contingency and growth. A thorium molten-salt reactor forward of mid-ships feeds an all-electric grid of five azimuthing thrusters and a bow tunnel. Nuclear choice removes the need for fuel bunkering, cuts local emissions and supplies reliable hotel and process power for multi-year campaigns. Equipment layout keeps the primary circuit far from accommodations and simplifies cable runs to large process motors.

Accommodation totals 5,905 m² and 16,628 m³ about 54 m² per person for an estimated 110-strong complement. Cabin mixes privilege six senior officers, reflecting offshore norms. Nuclear systems demand larger fire-fighting stores, radiation shielding between the reactor and living spaces and dedicated muster routes, all captured in SBSD’s safety block.

Total capital expenditure is 6,980 MNOK, including extraction unit and subsea pump. Roughly 82 percent lands in steel, outfit and machinery; build labor exceeds 0.9 million hours, or 20,069 NOK per lightweight ton. Relative ratios benchmark at 42,505 NOK per gross ton and 17,516 NOK per annual ton of ore capacity, comparing favorably with large FPSOs.

The concept relies on assumed resistance and propulsion data—model tests are needed to validate power demand for the full-bodied hull. Radiation zoning around the molten-salt reactor awaits class-society guidance. Shuttle-fleet sizing, particularly in winter weather windows, must be optimized alongside bulk-carrier charter costs. Addressing these items will push the design from concept toward class approval.