Navalyze · Oil tanker · Ship

WONDER ALTAIR

IMO: 9884825
Type: Oil tanker
Average cargo carried: 31,484 t
Flag (estimated): Marshall Islands
Port of registry: Majuro
Technical efficiency: EEDI 3.90 g CO₂/t·nm
Former names: CELSIUS PHILADELPHIA

ISM company (DoC holder) in 2025: Stainless 23 Ltd

Report year

2025 at a glance

From the 2025 THETIS-MRV report. Carries about 31,484 t of cargo on average.

Fuel kg/nm

83.5

Oil tanker median 129 kg/nm (−35%)

CO₂ per transport work (cargo)

8.32

g CO₂/t·nm · Oil tanker median 7.95 (+5%)

Average speed

11.4 kn

Oil tanker median 10.7 kn (+7%)

Fuel per day at sea

22.8 t/day

Fuel consumed

1,609 t

CO₂ emitted

5,050 t

5,129 t CO₂eq incl. CH₄ and N₂O

Distance sailed

19,277 nm

CO₂ ÷ CO₂ per mile

Time at sea

1,694 h

71 days, 19% of the year

Within the oil tanker fleet, 2025

Set against all 1,665 oil tanker ships with a full-year 2025 report. Bigger ships burn more per mile but less per tonne of cargo, so read fuel per mile with the ship's size in mind.

Fuel kg/nmThis ship 83.5 kg/nm · median 129 (−35%)

76.1Ranks 243 of 1,665, lowest first191

Average speedThis ship 11.4 kn · median 10.7 (+7%)

8.0Faster than 71% of oil tanker ships12.1

CO₂ per transport work (cargo)This ship 8.32 g CO₂/t·nm · median 7.95 (+5%)

4.51Ranks 896 of 1,665, lowest first27.7

Middle 80% of shipsMiddle 50%Oil tanker medianThis ship

Where the emissions happen, 2025

THETIS splits each ship's emissions by voyage type. The split sets how much falls under the EU ETS: all of it within the EU and at berth, half of it on voyages into or out of the EU.

Between EU ports8%
From the EU25%
Into the EU65%
At berth in the EU3%

16% of this ship's CO₂ falls under the EU ETS (783 t).

Fuel burned laden

991 t

62% of all fuel; 38% in ballast or unladen

CO₂ at berth

144 t

2.9% of the ship's CO₂, alongside in EU ports

Methane (CH₄)

0.1 t

Mainly from LNG; small for oil, biofuel and methanol

CO₂eq uplift

+79 t

+1.6% CO₂eq on top of CO₂ alone, from CH₄ and N₂O; counted in full from 2026

Over the years

Full-year reports only. The Oil tanker median is the middle ship of all oil tanker ships reporting that year; it moves with the fleet, so a ship can gain on it without changing itself.

Fuel kg/nm

WONDER ALTAIR
Oil tanker median

60.080.0100.0120.0140.0

’212021’222022’232023’242024’252025

Average speed, kn

WONDER ALTAIR
Oil tanker median

10.511.011.512.0

’212021’222022’232023’242024’252025

CO₂ per transport work (cargo), g CO₂/t·nm

WONDER ALTAIR
Oil tanker median

7.88.08.38.58.89.0

’222022’232023’242024’252025

Year on year

Year	Average speed	Fuel kg/nm	Fuel per day at sea	Distance	CO₂ per transport work	Reading
2024→2025	−0.5 kn	+0%	−4%	+21%	−3%	0.5 kn slower, fuel per mile flat; worse than speed alone explains (fouling, weather, loading or trade).
2023→2024	−0.1 kn	+25%	+25%	+174%	+4%	Same speed, fuel per mile up 25%; worse than speed alone explains (fouling, weather, loading or trade).
2022→2023	+0.8 kn	−18%	−13%	−57%	−7%	0.8 kn faster, fuel per mile down 18%; better than speed alone explains (hull, engine or trade).
2021→2022	–	–	–	–	–

Part-year reports are left out of these comparisons. Fuel per mile rises roughly with the square of speed for a given ship, so a change in speed explains much of a change in fuel per mile.

Every reporting year

One row per THETIS-MRV report. A ship that changed operator during a year has a part-year report for each.

Operation

Year	ISM company	Fuel t	CO₂ t	Distance nm	Hours at seah	Average speedknots at sea	Fuel kg/nmthis ship	CO₂ per transport work (cargo)g/t·nm, this ship	Laden fuel
2025part-year	Stainless 23 Ltd	1,125	3,526	13,591	1,184	11.5	82.8	8.72	88%
2025	CASTOR SHIPS S.A.	1,609	5,050	19,277	1,694	11.4	83.5	8.32	62%
2024	Stainless 23 Ltd	1,333	4,200	15,989	1,348	11.9	83.3	8.62	80%
2023	not published	387	1,206	5,833	488	12.0	66.4	8.28	58%
2022	not published	1,085	3,431	13,440	1,196	11.2	80.7	8.87	67%
2021	not published	0	0	–	0	–	–	–	–

Benchmark and verification

Year	ISM company	CO₂ per TW, g CO₂/t·nm	Oil tanker median	vs Oil tanker	Rank	Verifier	Methods
2025part-year	Stainless 23 Ltd	–	–	–	–	ABS	B+C
2025	CASTOR SHIPS S.A.	8.32	7.95	+5%	896 of 1,665	Bureau Veritas	A
2024	Stainless 23 Ltd	8.62	8.06	+7%	997 of 1,787	ABS	B+C
2023	not published	8.28	8.44	−2%	877 of 1,797	ABS	B+C
2022	not published	8.87	8.51	+4%	1,037 of 1,961	ABS	B+C
2021	not published	–	–	–	–	ABS	B+C

Fuel per mile and CO₂ per tonne-mile are the ship's own reported KPIs. Oil tanker ships are benchmarked on CO₂ per transport work (cargo) (TW), in g CO₂/t·nm. CO₂eq adds methane and nitrous oxide and is in the public files from 2024. Rank counts from the lowest figure among that year's oil tanker ships. Methods: A delivery notes, B tank monitoring, C flow meters, D direct measurement. FuelEU GHG intensity is not shown: it needs fuel types, which the public file does not carry. Operators are named only from 2024, the first year the public files carry them; earlier years belong to the ship, not to any company.