Sonabia 2: boring figures
Antarctica February 5 to March 2, 2023 6 persons,1484 nautical miles (nm), i.e., 2750 km. Total fuel consumption 671 liters, 232 engine hours. Averages: 2.88 L/ engine hour, 0.45 liter / nautical mile, 0.38 kg/nautical mile, 0.063 g/ person x nm
64 grams of combustible per mile and person
This corresponds to a very low carbon footprint: why?
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- Sailboats under sail do not use the engine (wow, great thinking).
- Under engine, low fuel consumption (relatively light boat, slow cruising speed, engine compliant with new European norms).
- There is no luxury, no need to waste fuel for excessive heating, strong illumination, bubble baths, etc.
Cruising ships: boring figures
On modern cruising ships, hybrid propulsion (electric motors + fuel or GPL generators) consume and contaminate less than classical heavy fuel engines [2].
Consumption figures are not public, however, here are safe estimates
For a small passenger ship, 200 passengers,in economical mode (observed on AIS: 13 knots in Antarctica) Pessimistic estimate : 100 tons of fuel or equivalent per day. Source [1]. 100 tons per day means 4167 kg/hour, 320 kg/nm, 1.6 kg/passenger x nm. Optimistic estimate: 20 tons of fuel or equivalent per day. Source. Consumption of modern cargo ships [3, table in 1], equivalence cargo ships - cruise ships of similar displacement, using a conversion factor 40% (gross tonnage vs. metric tons; data of several cruise ships available on the web) 20 tons per day means 833 kg/hour, 64 kg/nm, 320 g/passenger x nm.
320g to 1600g of combustible per mile and passenger
Clearly, passenger ships are not environment – friendly, even with modern propulsion systems. Actually, passengers ships consume more than cargo ships, for 2 reasons
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- Luxury. Facilities like illumination, heating, unlimited hot water, restaurants, etc. require energy (produces by engines and/or auxiliary generators).
- Speed. It is necessary to push the engines to meet deadlines and arrive fast on the touristic spots (observed on AIS: often above 18-20 knots).
Environment friendly? slow and rustic navigation
Sonabia 2: engine, Nanni 85HP, Euro norms.
Cruise ship: example of engine [2]
Sources: [1] https://www.marineinsight.com/know-more/how-much-fuel-does-a-cruise-ship-use/ [2] https://www.cruisemapper.com/wiki/752-cruise-ship-engine-propulsion-fuel [3] https://maritimepage.com/fuel-consumption-how-much-fuel-cargo-ship-use/ [4] https://www.cruisemapper.com/wiki/753-cruise-ship-sizes-comparison-dimensions-length-weight-draft
