Maritime Diversion Cost Calculator: What an Unplanned Medical Port Call Costs

What makes up the cost of a medical diversion?

When a vessel diverts to land an ill or injured crew member, the bill arrives in four parts. First, time: the vessel steams off-route to a port of refuge and back, and every extra hour carries the vessel's charter or opportunity cost. Second, fuel: the additional distance is burned at the vessel's service consumption, priced at current bunker rates. Third, the unscheduled port call itself: agency fees, pilotage in and out, towage, launch services, port and harbour dues — costs the voyage plan never budgeted. Gard's P&I Rule 31 captures the list precisely: the extra costs of 'fuel, insurance, wages, stores, provisions and port charges attributable to a diversion, over and above the costs that would have been incurred but for the diversion'.

The fourth part — the casualty's onward medical care, repatriation and crew replacement — usually lands with the P&I club rather than the voyage account, but it is real money in the industry averages. The calculator above estimates the first three parts for a single voyage; the sections below explain exactly how, and what is deliberately left out.

How the calculation works

The model is deliberately simple and fully inspectable. Extra time equals twice the one-way deviation distance divided by the vessel's speed, plus the hours spent in port. Time cost is that extra time multiplied by the vessel's day rate divided by 24. Fuel cost is the extra steaming time multiplied by the vessel's daily fuel consumption (converted to per-hour) and the bunker price per tonne. Port cost is a single line for the unscheduled call — agency, pilotage, towage, dues and launch services combined. The total is the sum of the three.

Every default is taken from a published source. Day rates come from Clarksons Research's 2025 full-year averages as reported by Riviera Maritime Media (container ship charter earnings US$45,287 per day; MR product tankers US$22,949; VLCCs US$63,160) and from Baltic Exchange dry bulk assessments (capesize around US$37,000, panamax around US$20,000, supramax around US$22,000 per day in July 2026). Offshore wind rates come from the BVG Associates / ORE Catapult guide: about £2,000 per day for a CTV and about £30,000 per day for an SOV, both excluding fuel. Speeds and fuel consumption are taken or derived from Table 35 of the IMO's Fourth GHG Study 2020 — the standard public reference for fleet-average speed over ground and fuel use per vessel class — and, for CTVs and SOVs, from ORE Catapult's O&M vessel benchmarking report (320 and 1,000 litres per hour in transit respectively). The bunker price default of US$500 per tonne of VLSFO sits between Ship & Bunker's forecast full-year 2025 global average of US$547 (published July 2025) and its sub-US$500 forecast for 2026.

The port call default of US$25,000 is an estimate assembled from published component figures — pilotage running to several thousand dollars per movement, tug call-outs of US$8,000 or more each, mooring gangs, agency and harbour dues — which put worked examples for a deepsea vessel in the US$10,000–31,000-plus range. Every input can be overridden, so operators with their own disbursement data can substitute real numbers.

What this calculator does not include

The estimate covers the voyage-level costs of one diversion: time, fuel and the port call. It deliberately excludes helicopter medevac (published government rates put a medium SAR airframe around US$15,000 per flight hour), the casualty's hospital treatment ashore, repatriation and crew replacement, off-hire and deviation disputes under the charterparty, cargo claims, schedule knock-on across subsequent fixtures, and P&I deductibles. It also excludes the operational cost of the disruption itself — a missed laycan or a lost weather window can dwarf the steaming cost.

This is why a single-voyage estimate often lands below the industry's all-in average. The most cited benchmark — approximately US$180,000 per medical diversion — comes from a 2013 study for the International Maritime Health Association covering 23,299 vessels. Its authors itemised roughly €78,750 in extra fuel, €25,000 for a helicopter evacuation and €60,000 in indirect costs such as crew replacement, arriving at a combined figure of about €163,750 — the basis for the US$180,000 per-diversion benchmark as cited by VIKAND. Run a panamax bulker through this calculator at the defaults — a 200-nautical-mile deviation and a 12-hour port stay — and you get roughly US$80,000: entirely consistent with the benchmark once you note that the helicopter, medical and indirect blocks are missing from the voyage-level number. Treat the calculator's output as the floor of the exposure, not the ceiling.

How operators reduce diversion exposure

The decision to divert always rests with the master, supported by the designated person ashore and, where evacuation is involved, the rescue coordination centre. Telemedicine does not move that authority — it changes the quality of the clinical information the decision rests on. A structured assessment by an experienced physician, in real time, replaces a lay description of symptoms relayed over a satellite link.

The published evidence suggests that this matters commercially as well as clinically. The IMHA study concluded that judicious use of telemedical assistance could reduce unnecessary medical evacuations by around 20% — a saving it put at some €152 million a year — and Ideagen cites industry data indicating that 30–50% of planned evacuations can be avoided through telemedicine consultation — because the condition can be safely managed on board with follow-up, or because the timing and destination of the landing can be planned into the schedule rather than forced onto it. The reverse case is equally valuable: earlier identification of a time-critical condition gives the master a clearer clinical basis for diverting or requesting evacuation without hesitation. The objective is never fewer diversions at any cost — it is the right decision, made on better information, every time.

Sources

• Henny et al., International Maritime Health (2013) — diversion cost itemisation (≈€163,750: fuel €78,750, helicopter €25,000, indirect €60,000), 23,299-vessel fleet, ~20% of diversions avoidable
• IMHA study cited by VIKAND — average medical diversion cost US$180,000; ~20% reduction in unnecessary diversions
• Ideagen (2026) — 30–50% of planned evacuations avoidable through telemedicine consultation
• Clarksons Research via Riviera Maritime Media (Jan 2026) — 2025 average earnings: container ship charter US$45,287/day, MR tanker US$22,949/day, VLCC US$63,160/day, tanker sector US$34,893/day
• Baltic Exchange dry bulk assessments via HandyBulk (July 2026) — capesize US$37,156/day, panamax US$20,236/day, supramax US$21,960/day
• BVG Associates / ORE Catapult, Guide to a Floating Offshore Wind Farm — CTV charter day rate ~£2,000/day (excl. fuel), speeds up to 30 kn
• BVG Associates / ORE Catapult, Guide to a Floating Offshore Wind Farm — SOV charter day rate ~£30,000/day (excl. fuel), operational speeds up to 15 kn
• IMO Fourth GHG Study 2020, Table 35 — fleet-average speed over ground and fuel consumption per vessel class and size (2018 activity data)
• ORE Catapult (2021), Setting a Benchmark for Decarbonising O&M Vessels of Offshore Wind Farms — CTV 320 l/h and SOV 1,000 l/h in transit; average transit speeds 23 kn and 12 kn
• Ship & Bunker (July 2025) — VLSFO global average US$547/t across full-year 2025; forecast below US$500/t through 2026
• Gard P&I, Rule 31 Diversion expenses — covered cost components: extra fuel, insurance, wages, stores, provisions and port charges attributable to a diversion
• Ship Universe — port call cost components: pilotage, towage call-outs from US$8,000/tug, mooring, harbour dues; worked examples US$10,680–31,000+
• US Coast Guard (2015) — H-60 helicopter reimbursable standard rate, US$14,979 per flight hour