AOG (Aircraft on Ground) Equivalent for Vessels: 6-Hour Service Plan
What 'AOG' looks like at sea: a six-hour service plan for vessels with a broken-down electrical system in port, structured around the four levers — diagnose remotely, ship the part, dispatch the engineer, paper the class.
The aviation comparison — and where it breaks down
In aviation, 'Aircraft on Ground' (AOG) means a specific thing: the aircraft cannot return to revenue service because of a single defect, and every hour on the ground costs the airline a measurable amount. The supplier network is structured around that fact. A part is dispatched from a regional hub, an engineer is rostered to receive and install it, and the paperwork to release the aircraft back to service is written in parallel with the work.
Vessels rarely use the AOG language, but the equivalent state happens regularly. A bulker waiting on a single 24V DC PSU for the cargo control system. A tanker that cannot complete a fuel oil transfer because the IAS lost a PLC analog input card. A container ship that needs an MSB feeder breaker replaced before the next port call. In each case the vessel is not 'down' — it can still float — but it cannot complete its commercial purpose. Every hour at anchor costs the operator. The supply and service chain that handles this state is what AOG-equivalent for vessels looks like.
The four levers — what gets pulled in parallel
An AOG-equivalent response runs four work streams in parallel, not in sequence. Sequencing kills the timeline. The four streams are: (1) remote diagnostic with the ship's electrician or duty engineer, (2) part identification and shipment dispatch, (3) engineer dispatch to the port of attendance, and (4) class and flag-state paperwork preparation. By the time the engineer arrives, the part is at the gate, the diagnostic is confirmed, and the report is half-written.
If any one of those streams is left until the previous one completes, the response cycle stretches from hours to days. The discipline of an AOG-equivalent service is to start all four within thirty minutes of the call, even when the cause is not yet known. The remote diagnostic is what disambiguates the part requirement; the part dispatch is what releases the freight before the courier cut-off; the engineer dispatch is what books the flight before the airport closes; the paperwork stream is what makes the survey sign-off a formality rather than a negotiation.
Hour 0 to 1 — intake and remote diagnostic
The intake call captures the bare minimum: vessel name, IMO, current port, agent contact, the system that is faulted, and the visible symptom. We do not ask for a part number on the first call. The ship's electrician usually does not have one to give yet, and asking forces them to interrupt the diagnostic to walk to the storeroom.
Within the first hour we connect to the ship's electrician by phone and walk the diagnostic. Most marine electrical faults can be narrowed down by symptom and a half-dozen targeted measurements. If the chief engineer is willing, we ask for photographs of the failed panel, the LED status pattern on the affected card, the nameplate of the upstream PSU, and any current alarm strings on the IAS. From those four artefacts, the experienced ETO on the diagnostic line can usually identify the part to the SKU level — and the supply line can start the part dispatch stream.
Hour 1 to 2 — part identification and dispatch
Once the SKU is identified, the supply line confirms stock at the nearest distribution hub. We hold a working spares inventory for the most common failure points on the systems we service: PLC analog input and output cards, 24V DC switched-mode PSUs, MCB and MCCB replacements in the most common ratings, contactors in the 18 A to 200 A range, common AVR boards, and common navigation system fans and PSUs.
If the SKU is in our inventory and the vessel is in a US port, the part can be on a same-day freight courier within sixty minutes. If the part has to come from a maker's distribution hub, we initiate the maker-to-courier handover in parallel with the engineer dispatch. The aim is to land the part at the agent's office or the vessel's gangway no later than the engineer's arrival.
Hour 2 to 4 — engineer dispatch
We hold a rostered duty ETO availability across the US East Coast, US Gulf and US West Coast. The engineer leaves the office or home with a pre-packed go-bag of test equipment and a vessel-specific case file generated from the intake call. By hour four the engineer is typically at the gangway of a vessel in any major US port — closer for the largest hubs (Houston, New York/NJ, Long Beach), further for outliers (Anchorage, Honolulu, Duluth).
The engineer arrives with the part if the part originated from our inventory, or arrives ahead of the part and stages the system for installation if the part originated from a maker's hub. The point is that the vessel does not wait for the engineer-and-part to arrive in series. By the time both are at the gangway, the diagnostic is confirmed, the install plan is agreed with the chief engineer, and the report template is open.
Hour 4 to 6 — installation, commissioning, paperwork
Installation timing depends on the part and the system. A 24V DC PSU swap is roughly twenty minutes plus a controlled re-energise. A PLC analog input card is forty minutes including the configuration upload from a backed-up project file. An MCB or MCCB replacement is sixty to ninety minutes including primary injection if the rating warrants it. An AVR replacement and commissioning runs three to four hours including load-step verification.
While the install runs, the report is being written in parallel. By the time the engineer signs off, the report includes the diagnostic chain, the measured values before and after, photographs of the defective and replacement parts, the calibration certificate IDs for any test equipment used, and the recommended forward-action items. The report is formatted to the requesting class society's template. The chief engineer receives the report by email before the engineer leaves the gangway.
What the vessel needs to do to make this work
Three things from the vessel's side compress the timeline more than any other factor. First: a duty engineer or chief electrician who can answer the diagnostic call and execute four to six measurements on instruction. Second: a gangway access pre-cleared with the agent and the terminal — getting an engineer through US port security with no prior coordination can add hours that none of the four work streams can recover. Third: a vessel-specific spares register that is up to date — if the ship's electrician knows that the failed card has a sibling installed in a parallel non-critical location, the diagnostic can validate the failure mode by swap-test before the new card arrives.
Operators that work with us regularly tend to keep a documented intake protocol on the bridge and in the engine control room: a single phone number, a single email address, and a one-page form that captures the four data points we need on the first call. That preparation reduces the intake-to-engineer-arrival cycle by a measurable amount.
How to start an AOG-equivalent dispatch
There is one entry point: the emergency lane in the service wizard, or the 24/7 number on the floating rail. The intake operator routes to the duty ETO immediately. We do not gate emergency intake behind a customer login or a form completion — that is a deliberate decision documented in the founding decisions log.
If the vessel is not yet in port but will be within the next 24 hours, the right move is to open the case now and let the diagnostic stream run in advance. The part can be staged at the agent's office before the vessel berths, and the engineer can be on the gangway as the lines are made fast.
FAQ
- What is the realistic shortest cycle time from call to engineer at the gangway?
- Roughly two to four hours at the largest US hubs (Houston, New York/NJ, Long Beach), four to six hours at most other US ports, longer for Alaska and Hawaii. Diagnostic and supply streams begin immediately regardless of the engineer-arrival cycle.
- Do we charge an emergency premium?
- Out-of-hours and emergency dispatch is priced on the same RFQ-first basis as planned work. The quote reflects courier and travel cost; there is no public price list.
- What if the part is not in any US distribution hub?
- We initiate the maker-to-courier handover in parallel, and stage the engineer for the install ahead of the part arrival. If a maker-direct shipment will not land in the survey window, we propose a documented equivalent and let the superintendent make the final call.
Open an emergency dispatch
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Pre-stage AOG spares
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