Slow steaming and CII: the speed lever

Service speed is the single largest lever an owner controls on the Carbon Intensity Indicator. The attained CII set by MEPC.336(76) is a ratio of annual CO2 emitted to transport supply, and main-engine fuel scales with roughly the cube of speed while distance scales only with the first power. Drop a Panamax bulker from 14 knots to 12 and main-engine fuel per day falls about 37 percent; the voyage takes 17 percent longer, so auxiliary burn over the leg rises a little, but the net annual CO2 still drops far faster than the modest loss of distance. That asymmetry is why two knots can move a ship across a full rating band when no other operational measure can. This article works through the mechanism, the band arithmetic, the year-on-year tightening trajectory, the corrections that interact with speed, and the fleet-level cost of holding a schedule once you slow down. The numbers tie back to the CII Attained calculator and the Slow Steaming calculator so you can reproduce them on your own ship.

How CII is measured: AER, not actual cargo

CII for the great majority of cargo ships is the Annual Efficiency Ratio. AER divides total annual CO2 in grams by the product of the ship’s deadweight in tonnes and the total distance sailed in nautical miles. The unit is grams of CO2 per deadweight-tonne-nautical-mile. The choice of deadweight, not cargo carried, is the defining design decision of the metric and the source of most of its quirks. A ship gets credit for its full carrying capacity on every mile, loaded or in ballast, so the denominator is fixed the moment the keel is laid. The numerator, total CO2, is the only term an operator can change from one year to the next.

CO2 is computed from fuel, not measured at the funnel. Each fuel’s mass burned over the year multiplies by a carbon-conversion factor Cf, the tonnes of CO2 produced per tonne of fuel. VLSFO and HFO carry a Cf of 3.114; MGO sits at 3.206; LNG, on a tank-to-wake basis under the current guidelines, is 2.750 before any methane-slip adjustment. The fuel data comes straight from the ship’s IMO Data Collection System report, the same Statement of Compliance machinery that already underpins the bunker-delivery-note reconciliation. So the AER chain runs fuel to CO2 to a ratio against a fixed denominator. Because distance and deadweight are both fixed for a given trading pattern, attained CII moves almost linearly with annual fuel. Halve the fuel and you roughly halve the attained value. That linearity is what makes slow steaming so direct: the saving you compute on a single voyage carries through to the annual rating without dilution.

The DCS reporting boundary matters here. The fuel counted is everything consumed between the first departure and the last arrival of the calendar year, including time at anchor, in port if the main or aux engines run, and on ballast repositioning. The distance counted is the distance over ground actually sailed. There is no carve-out for a long ballast leg or a slow-steamed weather diversion; both add CO2 and distance, but only the CO2 hurts the ratio if the extra miles do no transport work. The interaction of idle time, ballast distance, and the cube law is where the metric stops being intuitive, and it is where most of the year-end surprises come from.

The CII framework under MEPC.336(76) applies to cargo, ro-pax, and cruise ships of 5,000 gross tonnage and above on international voyages, the same population that already reports under the IMO DCS since the 2019 reporting year. The metric went live for the 2023 calendar year, so the first Statements of Compliance carrying a letter grade were issued in 2024 against the 2023 data. That timing means the operational track record an owner is graded on began the moment the rule took effect, with no run-in period; a ship that steamed hard through 2023 in ignorance of the trajectory carries that year into its three-year D-rating count. The metric is annual and backward-looking, so a speed policy set in mid-year can only fix the remaining months, which is why the speed decision is usually framed as a full-year budget rather than a per-voyage one.

There is a second, finer point about the denominator that bites on short-sea trades. Distance over ground includes every mile of a coastal zig-zag, of a deviation around traffic separation schemes, and of a current set, so two ships of equal deadweight on the same nominal route can post different AER values purely from how their masters were routed. A ship pushed off the great-circle track by 8 percent of extra distance dilutes its CO2 over more miles and so reads a lower AER, which is one of the metric’s perverse incentives discussed under the limitations below. For the slow-steaming decision the practical consequence is that the distance term is not as fixed as the deadweight term; it moves with routing, and an owner optimizing CII should hold routing constant when sizing a speed cut, or the two effects will tangle.

The cube law: speed to power to SFOC to CO2

The physical reason speed dominates the ratio is the relationship between vessel speed and the power the propeller has to deliver. For a displacement hull in its normal operating band, delivered power rises with speed raised to an exponent near three:

The admiralty-style exponent $n$ sits near 3 for most full-form ships. Tankers and bulkers, with blunter bows and slower design speeds, run closer to $n = 2.8$. A modern fine-form container ship pushing into its wave-making regime can climb to $n = 3.2$ or higher near the top of its speed range. The Speed-Power Cubic Fit calculator lets you regress your own sea-trial or noon-report pairs to get the exponent for a specific hull rather than assuming three.

Power is not the whole story, because the engine does not burn fuel in exact proportion to power. Specific fuel oil consumption, the grams of fuel per kilowatt-hour, varies across the load curve. A modern slow-speed two-stroke is tuned for a best-SFOC point somewhere between 70 and 85 percent of MCR; pull the load down below about 40 percent and SFOC creeps back up as combustion efficiency falls and friction takes a larger share. So the fuel saving from slowing down is the cube-law power drop multiplied by the longer running hours, then adjusted by the way SFOC drifts at the new load. The chain from speed to attained CII runs through every one of those links.

A worked version makes the cube concrete. Take a bulker on a 6,000 nautical mile loaded leg, reference speed 14 knots, main-engine consumption 42 tonnes a day at that speed, auxiliary load a flat 3 tonnes a day, burning VLSFO at Cf 3.114. At 14 knots the leg takes 429 hours; main-engine fuel is about 750 tonnes and aux about 54 tonnes, so 804 tonnes total and 2,504 tonnes of CO2. Slow to 12 knots and the power ratio is $(12/14)^3 = 0.63$, so the main-engine rate drops to roughly 26.5 tonnes a day; the leg now takes 500 hours, so main-engine fuel falls to about 552 tonnes and aux rises to 62 tonnes. Total fuel is 614 tonnes, CO2 about 1,912 tonnes. The two-knot cut saved 24 percent of voyage CO2 against a 17 percent increase in time. Push to 10 knots and the power ratio is $(10/14)^3 = 0.36$; main-engine fuel drops to roughly 380 tonnes over the now 600-hour leg, aux climbs to 75 tonnes, total 455 tonnes, CO2 about 1,417 tonnes, a 43 percent CO2 cut. The aux term is what eventually limits the benefit: at very low speed the hotel and engine-room load runs for so many extra hours that it claws back part of the main-engine saving. You can vary speed, rate, and exponent on the Slow Steaming Fuel Savings calculator to find the fuel-optimum speed for a specific leg.

The same numbers carried up to a full year show why the per-voyage cube law dominates the annual rating. Run that bulker on a trading pattern of 80,000 nautical miles a year at the 14-knot pattern and it burns on the order of 5,000 tonnes of fuel, posting roughly 15,500 tonnes of CO2; at 82,000 deadweight the attained AER works out near 2.37 grams per deadweight-tonne-nautical-mile, which falls in the D band for most bulker size bins under the 2023 required line. Hold the same miles at the 12-knot pattern and the annual fuel drops toward 2,700 tonnes, CO2 near 8,400 tonnes, and the AER falls to about 1.28, which clears into A or B. Two knots moved the ship two full bands, and no other single operational change comes close. Feed the annual fuel figure straight into the CII Attained calculator and the band drop reproduces.

The SFOC drift on a real engine sharpens the picture at the low end. A MAN B&W or WinGD slow-speed two-stroke specified for a best-SFOC point around 75 percent MCR might burn 165 grams per kilowatt-hour there; pull it down to 30 percent load and that can rise toward 175 to 180 grams per kilowatt-hour, a 6 to 9 percent SFOC penalty that partly offsets the cube-law power saving. So the fuel saved from a deep speed cut is the cube-law power drop, multiplied by the longer hours, divided by the worsened specific consumption. The CII SFOC and Fuel Mix quick check lets you put your engine’s actual SFOC curve into the chain rather than assuming a flat figure, which matters once a ship is steaming below 40 percent MCR for most of the year.

Required CII and the 2 percent annual trajectory

Attained CII means nothing on its own. It is graded against a required CII that tightens every year. The reference lines in MEPC.337(76) set, for each ship type and size bin, the median 2019 carbon intensity from the IMO DCS data. The required line for a given year is that reference value cut by a reduction factor, the Z factor, defined in MEPC.338(76). The published factors are 5 percent for 2023, 7 percent for 2024, 9 percent for 2025, and 11 percent for 2026, each measured against the 2019 baseline. That is a 2-percentage-point reduction step every year, so a ship that does nothing watches its required line drop while its attained value stays put.

The arithmetic of holding a rating is straightforward once the Z steps are clear. Suppose a ship sits exactly on its required line in 2023, a borderline C. In 2024 the required line tightens by roughly 2.1 percent of the 2019 baseline relative to 2023; to stay on the same band boundary the ship must cut attained CII by about the same amount. Because attained CII tracks annual fuel almost linearly, a 2-percent cut in attained CII is close to a 2-percent cut in annual fuel. Through the cube law, a 2-percent fuel cut on the main-engine portion comes from a speed reduction of roughly 0.7 percent at $n = 3$, since $1 - (1 - 0.02)^{1/3} \approx 0.0067$ on the power term, adjusted upward for the aux fuel that does not scale. In rough numbers, a ship needs to shave on the order of a tenth of a knot a year off its loaded average just to hold station against the trajectory, before any margin for fouling or weather. Hold the line from 2023 to 2026 and the cumulative cut is the difference between the 5 percent and 11 percent factors, about 6.3 percent of the 2019 baseline, which translates to roughly half a knot off the 2019 service speed for a typical bulker. The CII Required Line calculator returns the exact required value for a ship type, size, and year; the CII Attained vs Required calculator shows the headroom or deficit in the rating’s own d-vector terms.

The trajectory beyond 2026 is not yet set in the same numerical form. MEPC.354(78) refreshed the G1 calculation guidelines and the working groups under the revised IMO GHG Strategy adopted in 2023 are reviewing the post-2026 reduction factors and the entire CII framework as part of the phase the IMO calls the 2026 review. An owner planning a five-year speed policy should treat the 11 percent 2026 factor as a floor, not a ceiling, and assume the steps continue. The year-on-year CII improvement calculator helps frame how a fixed annual fuel cut tracks against an assumed continuation of the 2-point cadence.

Rating bands and the d-vector boundaries

The five-grade rating in MEPC.339(76) is what shows on the Statement of Compliance and what charterers read. The grades run A, B, C, D, E from best to worst. The boundaries are not fixed gram values; they are set as multipliers of the required CII through four boundary coefficients called the d-vector, distinct for each ship type and size band. The attained value is divided by the required value, and the ratio is placed against the d1 through d4 cut points. A ratio at or below d1 is an A. Between d1 and d2 is a B. Between d2 and d3, straddling 1.0, is a C, the band that means roughly on-line with the required value. Between d3 and d4 is a D, and above d4 is an E.

The width of the C band is what determines how much speed change a given ship needs to cross a boundary, and the d-vectors make that width type-specific. For bulk carriers the d-vector is approximately 0.86, 0.94, 1.06, 1.18, so the C band runs from a ratio of 0.94 to 1.06, a span of 12 percent of the required value. A ship sitting at the middle of D, say a ratio of 1.12, needs to cut attained CII by about 6 percent just to reach the D-to-C boundary at 1.06, and by about 18 percent to reach the C-to-B line at 0.94. Through the cube law those are speed cuts of roughly 2 and 6 percent on the power term. For a tanker the d-vector is near 0.82, 0.93, 1.08, 1.28, a wider band on the low-rating side, so a tanker drifting into E has further to climb. The point that catches owners is that the bands are multiplicative: a ship that has slipped two bands needs a fuel cut measured in the high teens of percent, which is a speed reduction of a knot or more, not a trimming exercise. The CII Rating calculator and CII Rating by Year calculator place a candidate attained value into the correct letter for the type, size, and year, including the moving required line.

A D rating is not an immediate sanction, but three consecutive D years, or a single E year, forces a corrective action plan in the ship’s SEEMP Part III under MARPOL Annex VI Reg.28. The plan must show how the ship returns to at least a C. Speed reduction is almost always the cheapest line item in that plan, which is why a slipping rating and a slow-steaming decision tend to arrive together. The corrective-action arithmetic, how much annual fuel a ship must shed across the remaining trading days to climb back above the D-to-C line, is set out in the CII Corrective Trajectory calculator.

Correction factors and voyage adjustments

The attained CII is not the raw fuel-to-distance ratio in every case. MEPC.355(78) and the G5 guidance allow a set of correction factors and voyage adjustments that remove fuel or distance from the calculation when the consumption did no productive transport work or was forced by a regulatory or safety requirement. These adjustments change the baseline against which a speed decision is measured, so they have to be folded in before an owner concludes how much slow steaming a ship actually needs.

The voyage adjustments cover legs where the ship was doing something other than ordinary trading. Fuel and distance attributable to a documented period of ice transit through ice classes, to escape from a port under a force-majeure or safety order, or to operating in a recognized war or piracy high-risk area can be deducted. The correction factors cover ship characteristics: a cargo-heating allowance for chemical and oil tankers, an electrical-load allowance for reefer-heavy container ships and gas carriers running cargo plant, a shuttle-tanker dynamic-positioning allowance, and an ice-class structural correction. Each one shrinks the attained value, and each one is documented through the verifier who issues the Statement of Compliance.

The interaction with slow steaming is subtle. A ship that already pulls a large reefer correction has a softer required-line problem than its raw fuel suggests, so it may need less speed reduction to hold a band. A tanker on a long cargo-heating trade keeps a fixed heating burn that does not fall when the ship slows; the heating fuel is corrected out, but the time the heating runs grows with the longer voyage, and only part of that is recoverable. The general rule holds: apply the corrections first, recompute the adjusted attained value, then size the speed cut against the adjusted figure rather than the raw one. The CII Fuel Mix Correction calculator handles the multi-fuel side of the numerator, which matters once a ship runs a blend of VLSFO, MGO, and a low-carbon fuel with different Cf values.

Fleet and schedule consequences of slowing down

A single ship can slow down whenever the charter allows. A liner service cannot, and that constraint reshapes the whole economics. A container loop on a weekly fixed-day rotation runs a string of ships sized so that the round trip divides evenly into the service frequency. Drop the speed and the round-trip time grows; to keep the weekly cadence and the same port rotation, the operator has to add a ship to the string. A loop that ran with eight ships at 18 knots might need nine at 16, or ten at 14. The added vessel is the real cost of slow steaming on a scheduled service, and it is a step cost, not a smooth one.

The trade-off is between bunker savings and the daily cost of the extra hull. If slowing from 18 to 16 knots saves enough fuel across the string to more than cover the time-charter-equivalent of one extra ship, the slower string is cheaper and lower in carbon intensity. When bunker prices spiked in 2022 and again under the cost of compliant fuel, the math favored adding ships on most deep-sea container loops; when bunkers are cheap and charter rates high, the faster, fewer-ships string wins on cost even though it scores worse on CII. The CII rating turns this from a pure cost optimization into a constrained one: the operator now has a rating floor to defend as well as a freight bill. The SEEMP Combined Operational Measures calculator lets a fleet planner stack speed, hull cleaning, and routing savings to see whether the combined effect clears a target band without the extra ship.

Bulk and tanker operators face a different version of the same problem. They are not on fixed schedules, but they are on charter parties with laytime, demurrage, and warranted speed clauses. A bulker that slows to protect its rating may breach a speed warranty or arrive after a laycan, exposing the owner to off-hire or a claim. Just-in-time arrival softens this: if the ship would otherwise wait at anchor for a berth, slowing the approach to arrive exactly when the berth opens saves the cube-law difference with no schedule penalty, because the anchor time was dead time anyway. IMO Resolution MEPC.323(74) invites port and ship cooperation on just-in-time operation, and the fuel it unlocks is the cheapest carbon-intensity gain available, since it changes nothing about the commercial voyage except removing idle steaming.

How this stacks with EEXI, EPL, and ShaPoLi

CII is an operational metric; EEXI is a design one. The Energy Efficiency Existing Ship Index under MEPC.328(76) sets a one-time limit on a ship’s design carbon intensity, and a large share of the existing fleet met it by capping engine power rather than rebuilding the hull. Two mechanisms do that capping. An Engine Power Limitation caps the fuel-rack or governor setting so the engine cannot exceed a stated MCR. A Shaft Power Limitation does the same at the shaft via a torque-and-speed monitor. Either one lowers the maximum continuous power and therefore the maximum attainable speed.

A ship with an EPL set at, say, 70 percent of original MCR has already lost the top of its speed range. Through the cube law, capping power at 70 percent caps top speed at $(0.70)^{1/3} = 0.89$ of the original, so a ship that did 15 knots flat out now tops out near 13.3 knots. That cap is permanent unless an overridable EPL is engaged under the documented conditions for which the override exists. For CII purposes, the EPL ship has had part of its slow-steaming decision made for it: it physically cannot run the high-speed, high-fuel pattern that would push attained CII into D or E. The relationship is detailed in the article on engine derating for slow steaming and on EEXI. An owner who set the EEXI EPL conservatively, then finds the CII trajectory tightening, may have little operational margin left, because the easy slow-steaming room was already spent on the design index.

The two metrics can therefore pull in step or against each other. A deep EPL helps the early CII years because it forecloses fast steaming, but it also removes the schedule-recovery option of speeding up after a delay, which the BIMCO clause and a tight laycan may both demand. A ship with a shallow EPL keeps that recovery option but has to manage CII actively through voluntary speed policy. The design choice made at the EEXI compliance date in 2023 thus shapes the operational room for the rest of the ship’s life under CII. The wider regulatory frame for both indices sits in MARPOL Annex VI.

Charter-party CII clauses and who pays for slowness

Slow steaming for the owner’s rating can directly conflict with the charterer’s commercial interest in a fast delivery. On a time charter the charterer gives voyage orders and burns the bunkers; on a voyage charter the owner does. The CII rating attaches to the ship and the owner, but in a time charter the speed that drives it is set by the charterer’s orders. That split of control and consequence is what the charter-party CII clauses try to resolve.

The BIMCO CII Operations Clause for Time Charter Parties, published in November 2022, is the most used wording. It obliges the parties to cooperate so the ship can meet its agreed CII profile, requires the charterer to issue voyage orders consistent with that profile, and sets out how the rating outcome and any corrective costs are shared when orders push the ship below the agreed line. The mechanics, what counts as a permitted deviation, how a forced speed-up for safety is treated, and how an end-of-year deficit is allocated, are exactly the kind of cost-split a charter desk negotiates line by line. The detail and the variants are covered in the article on BIMCO CII clauses, and the cost-allocation arithmetic is built into the BIMCO CII Operations Clause cost-allocation calculator.

The points that get fought over are concrete. A warranted speed range, often something like 11 to 13 knots at no more than 85 percent MCR, fixes the band within which the charterer may order. A cap on time above a stated MCR limits the fast-steaming bursts a charterer can demand for a single hot cargo. A bonus-malus on the year-end rating shares the upside and downside. And a fuel-saving split lets the owner keep part of the benefit when it optimizes below the warranted speed. Owners who sign a charter without a CII clause, then receive orders that drive the ship to a D, end up absorbing the corrective-plan cost even though the speed was the charterer’s call. The clause is the contractual counterpart to the cube-law physics: it decides who pays for the slowness that the rating rewards.

Other operational levers that stack with speed

Speed is the largest single lever but not the only one, and the others matter because they let an owner hold a band with a smaller speed cut, preserving schedule flexibility. Hull and propeller condition is the next biggest. A fouled hull can add 5 to 10 percent to required power at constant speed; a hull cleaning or a propeller polish recovers most of that, though the gain fades over the following 6 to 12 months as fouling returns. Trim optimization on a modern hull is worth 1 to 3 percent per voyage at no capital cost beyond the loading-computer work. Weather routing saves 3 to 5 percent on trans-ocean legs by avoiding the head seas that spike added resistance. Waste-heat recovery, a capital retrofit, can displace 4 to 8 percent of main-engine fuel by generating power from exhaust and steam that would otherwise be lost. Energy-saving devices, covered in the article on energy-saving devices, and hull-form retrofits such as a bulbous bow change add a few more percent each.

These stack roughly additively in the small-percentage range. A ship that recovers 6 percent from a hull clean, 3 percent from trim, and 4 percent from routing has cut attained CII by about 12 percent without touching speed, which through the cube law is equivalent to a 4 percent speed reduction it did not have to make. Combine that with a deliberate 2-knot slow-steam and the total fuel cut runs to the high forties of percent, enough on most bulkers to move from a D to a comfortable B. The practical reading is that an owner should exhaust the no-schedule-cost levers first, then use the speed cut to close whatever gap remains, because every percent recovered elsewhere is a percent of schedule flexibility kept. The full operational picture is in the article on slow steaming, and the foundational definition is in what is CII.

Limitations

The AER metric measures deadweight, not cargo moved, and that is its largest flaw for slow-steaming decisions. A ship that runs a long ballast leg burns fuel and adds distance, but the deadweight in the denominator is the same full capacity it would carry loaded, so the ballast leg still scores against the ship even though it did no transport work. A ship with a high loaded-to-ballast ratio is rewarded for a trading pattern it may not control, and slowing the ballast leg helps the rating without doing anything for actual cargo efficiency. The cargo-carried alternative, cgDIST, exists in the guidelines for some ship types but is not the default, so most ships live with the deadweight denominator and its distortions.

Idle and port time distort the annual figure in the other direction. Fuel burned at anchor or in port while engines run counts in the numerator, but the ship covers little or no distance during it, so a year with long waiting times can push attained CII up regardless of how carefully the ship was steamed at sea. A slow-steaming policy aimed at the sea passage does nothing for the anchorage burn, and a ship stuck in congestion can slip a band on idle time alone. The metric rewards keeping moving, which is not always within the operator’s gift.

The cube-law saving weakens at very low load. Below roughly 40 percent MCR the main engine’s SFOC rises, fouling of the turbocharger and scavenge spaces can occur on engines not designed for sustained low load, and the auxiliary burn over the longer voyage eats further into the main-engine saving. There is a floor speed below which slowing further costs more in time and auxiliary fuel than it saves, and that floor is ship-specific. Pushing past it to chase a rating can damage the engine and raise total fuel, the opposite of the intent.

Speed reduction alone may not move a ship across a band. The d-vector boundaries are wide for some types, so a ship deep in D may need a fuel cut in the high teens of percent, a speed reduction of more than a knot, which a schedule or a charter warranty will not allow. In those cases the rating cannot be fixed by speed inside the year, and the corrective plan has to lean on hull work, retrofits, or a fuel switch. Treating speed as a universal fix overstates what one lever can do.

The gaming critique is structural. Because the denominator is deadweight, a larger ship gets a better AER for the same transport task, so the metric can favor building or chartering bigger tonnage rather than emitting less per tonne of cargo. A ship can also improve its AER by sailing more miles at the same fuel rate, which rewards distance over efficiency in some edge cases. The IMO working groups have flagged these effects, and the post-2026 review under the revised GHG Strategy is examining whether the metric, the reference lines, and the rating bands need restructuring. Until that review concludes, slow steaming remains the most direct operational change available on a metric that everyone agrees is imperfect, and the speed decision should be made against the adjusted, correction-applied attained value rather than the raw ratio, with the engine’s low-load floor and the charter’s speed warranty both treated as hard constraints.

A further limitation is that the rating compares a ship against a 2019 fleet median frozen in the reference lines, not against the ship’s own historical best. A vessel that was already efficient in 2019 has little room to improve before it hits its engine’s low-load floor, while a ship that was a fleet laggard can post large year-on-year gains from the same speed cut. The metric therefore measures position relative to a static peer median, not absolute progress, and a careful owner cannot read a C rating as a steady-state target because the required line keeps moving under it. The reference lines themselves are type-and-size specific, so a ship that changes trade in a way that shifts its effective size category, or a converted vessel that no longer matches its original type bin, can find its required line and band thresholds no longer represent its real operating profile. These are the cases where a verifier discussion under the MEPC.339(76) rating guidance, rather than a speed change, is the right response.

Finally, the metric says nothing about the carbon content of the energy a ship buys. Two ships burning identical fuel mass score identically on AER even if one runs a bio-blend and the other straight HFO, except through the Cf difference, which is small for drop-in fuels. A genuine decarbonization step such as a switch to methanol or ammonia shows up only through its lower Cf, and the well-to-wake emissions that dominate the climate question sit entirely outside the tank-to-wake CII boundary. Slow steaming and a fuel switch are therefore complementary, not substitutes: the speed cut lowers the fuel mass, the fuel switch lowers the carbon per tonne, and a serious five-year compliance plan needs both because the post-2026 reduction factors are widely expected to outrun what speed reduction alone can deliver.

See also

Calculators

• CII Attained calculator
• Slow Steaming Fuel Savings calculator
• Slow-Steaming GHG, CII Rating Sensitivity
• Speed-Power Cubic Fit calculator
• SEEMP Combined Operational Measures
• CII Required Line by Year
• CII Rating by Year
• CII Attained vs Required
• CII Corrective Trajectory
• BIMCO CII Operations Clause cost allocation

Related wiki articles

• Slow steaming
• What is CII
• What is EEXI
• Engine derating for slow steaming
• BIMCO CII clauses
• MARPOL Annex VI
• Energy-saving devices
• Bulbous bow retrofits