The deck log, written the way the watch is kept.
Offline on the ship. Signed before it is official. Ready when the surveyor asks.
Written from the bridge. At sea since 2002, deep-sea master since 2018.
| Time | Position | Co / Spd | Wind · Sea |
|---|---|---|---|
| 0500 | 36°12.4′N 014°48.9′Esigned · 2/O |
097° / 12.6 | NW 4 · 3 |
| 0600 | 36°10.1′N 015°04.3′Esigned · 2/O |
097° / 12.4 | NW 4 · 3 |
| 0700DRAFT | 36°07.9′N 015°19.6′Esrc: NMEA 0183 GGA · GPS1 |
097° / 12.5src: NMEA VTG | NW 5 · 3src: manual |
Illustrative screen. Sample values, not a real voyage.
The paper log is honest. It is also slow, and it is hard to search.
Corrections, strike-throughs, handwriting at 0400
A wrong figure gets a single line and initials. After a heavy-weather watch the page is correct and almost unreadable, and the next officer has to work out what the handover actually said.
The same noon position typed four times
Deck log, noon report, the office email, the charterer's form. Each copy is one more place for a transposed digit, and nobody can say which one was first.
Flipping pages while the inspector waits
"Show me the steering gear tests for the last two weeks." The entries exist. Finding them across three books and two months, with the PSC officer standing at the chart table, is the hard part.
One record. The ship writes it, the office reads it.
The ship keeps working with no internet. The office gets a copy, not the right to overwrite a signed entry.
On the ship
Primary record- Watch flow in paper-log order. Hourly position, handover, soundings, weather, steering, engine movements.
- Offline core. Runs on the bridge with no link. Recording never waits for the office.
- Drafts from sensors and voice. NMEA 0183/2000, Signal K and voice notes prefill a draft. The officer confirms.
- Signature closes the entry. Officer of the watch signs; master countersigns where the book requires it.
- Audit mode on board. A fixed PDF and hash chain for any date range, without calling the office.
In the office
Synced copy- Fleet daily. One view of the last signed entries across the fleet.
- Missing watches. Unsigned or absent watch entries, flagged per vessel and per day.
- ORB consistency. Oil Record Book entries that do not add up, raised for the ship to check (MARPOL phase).
- Revisions, not overwrites. An office correction becomes a separate, named revision with a reason.
- Export. PDF and structured data for the DPA, the superintendent, or an investigation.
Not a fleet-performance or voyage-optimisation suite.
Built from the watch, not from a form.
The watch flow was written by a master
Entries come in the order a paper deck log is kept: hourly position, watch handover, soundings, weather, steering, engine movements. An officer who knows the paper book knows where to type.
Offline on board. The ship's entry wins.
The core runs on the ship. When the link drops, recording carries on. When it returns, the office syncs. If both sides changed the same entry, the ship's signed entry stands and the office change is kept as its own revision.
Sensors draft. Officers record.
NMEA 0183/2000 and Signal K fill a draft with time, position, course, speed, wind, depth and engine hours. The source is shown on the line. A sensor reading is never the official record until the officer confirms it.
A voice note opens a draft, nothing more
Speak the entry on the bridge wing and a draft appears. It does not lock until the officer has read and signed it. If the transcription invents something, it is corrected before signing and never reaches the audit trail.
Deck log first. Engine and MARPOL books after it is stable.
For merchant ships, not yachts. One book is finished properly before the next one starts.
| Book | Scope | Status |
|---|---|---|
| Deck log | Watch entries, positions, weather, steering, soundings, master's remarks. | First · in development |
| Engine log | Watch readings, engine movements, running hours. | Next |
| Oil Record Book Part I | Machinery space operations, MARPOL Annex I. | MARPOL phase |
| Oil Record Book Part II | Cargo and ballast operations on oil tankers, MARPOL Annex I. | MARPOL phase |
| Garbage Record Book | Discharges and incineration, MARPOL Annex V. | MARPOL phase |
| Ballast Water Record Book | Uptake, treatment and discharge under the BWM Convention. | With MARPOL books |
Pick the days the inspector asked for. Hand over a closed package.
Audit mode builds a fixed record for a chosen date range: an unchangeable PDF in the page layout a surveyor expects, the hash chain that proves nothing was edited afterwards, every signature, and who entered each line.
Port State Control usually asks for a specific window: the last 14 days of steering gear tests, the arrival draft, the passage plan check. Choose the range, print or send the PDF, and keep looking at the officer, not the pages.
- RangeAny span of days, fixed at export. Later revisions are listed, not merged in.
- DocumentRead-only PDF, laid out like the paper book page by page.
- IntegrityEach entry carries the hash of the one before it. A changed line breaks the chain.
- SignaturesOfficer of the watch, master, and any office revision with name, time and reason.
- ProvenanceFor every value: typed, sensor draft, or voice draft, and who confirmed it.
Illustrative package. Hashes and names are placeholders.
The ship does not wait for the satellite.
Every entry is written on board first. The office copy follows when there is a link, and once it lands, the signed record exists in two places.
Written on board first
The ship system is the primary record. A lost link, a slow VSAT or a dead office server does not stop an entry or a signature.
Synced when the link returns
Queued entries go to the office in order, with their hashes, so the office copy can be checked against the ship's chain.
On conflict, the ship's entry wins
If the office changed something the ship also changed, the ship's signed entry stands. The office change is kept as a separate revision with name, time and reason. Nothing is overwritten.
Two copies of the signed record
After sync the signed record is held on board and in the office. Either side can rebuild an audit package without the other.
Illustrative log. Times in UTC.
Not class approved. Not flag accepted. Here is the order we intend to apply.
The design follows the electronic record book principles of IMO resolution MEPC.312(74).
Type approval and flag acceptance are applied for only after the ship system is stable on board. Until then, the paper book stays the official record.
- Now
Design to MEPC.312(74)
Signatures, audit trail, tamper evidence and export built in from the first entry.
- Next
Deck log stable on board
Trial vessels run it alongside the paper log until watchkeepers trust it.
- Then
Apply for type approval
Application to a classification society for the deck log, once the ship system is stable.
- Then
Apply for flag acceptance
Applications flag by flag, following each administration's own process.
- After
Engine and MARPOL books
Engine log, ORB I/II, Garbage and Ballast Water record books, through the same steps.
If you need an approved electronic log on board today, NAVTOR and NAPA have type approvals and flag acceptances in place and are proven across large fleets. We are building something narrower: a deck log shaped by the watch, offline first, with the ship's signed entry as the record.
Written from the bridge. At sea since 2002, deep-sea master since 2018.
Pelorus is built by a serving merchant master who has kept the deck log as a cadet, as officer of the watch and as master, and has opened it for port state, flag and class inspections more times than anyone keeps count of.
The screens follow the paper book because that is how watchkeepers already think. The rules come from the bridge: nothing becomes official until an officer signs it, and nothing the office does can quietly change what the ship signed.
Tell us about your ships.
We are looking for a small number of operators to run the deck log on board alongside the paper book.