Maintenance records and documents nobody can quietly rewrite

Questions technical managers ask

Is this a real blockchain or a database with hashes?

It is a hash-linked chain with the same tamper-evidence property a blockchain provides: each block commits to its parent, so history cannot be altered without detection. It runs without a public token or gas fee, and public checkpoints let any outside party verify the chain independently — you get the same after-the-fact tamper-evidence — the order and content of what was sealed cannot be altered — without asking a ship's crew to hold a crypto wallet over a satellite link.

What does the timestamp on a sealed entry mean?

It records the moment the entry was sealed, not the moment the work was done. Jobs, certificates and documents are sealed when a person seals them from the ledger console, so a job completed three weeks earlier carries the date it was sealed. Change history is sealed automatically approximately hourly at 25 minutes past the hour, so a recorded edit waits no longer than the next hourly seal before a block covers it; a published checkpoint is produced daily at approximately 02:35 UTC. The chain proves that the sealed entries have not been reordered, backdated or amended since — it does not prove when the underlying work happened.

What can actually be sealed?

Maintenance jobs and their completions, statutory and class certificates, evidence documents and photographs, requisitions and spare-part stock movements — sealed from the ledger console. The change history itself — recorded edits to a maintenance schedule, tolerance, sign-off or reading — is sealed into the same chain automatically approximately hourly at 25 minutes past the hour, and a published checkpoint is produced daily at approximately 02:35 UTC. Anything sealed can be re-verified at any moment against the live record.

Can a record still be corrected after it is sealed?

Yes. A correction is sealed as a new entry and the original entry stays in the chain with its original fingerprint, so nothing is silently overwritten — the sequence of states is the evidence. Verification also compares each sealed record with the live row and reports any that have changed since sealing. In plain terms: no record in this workspace has yet been corrected after sealing, so treat this as how the mechanism behaves rather than something we have watched happen in service.

Does the chain prove everything that happened was recorded?

No — and you should hold us to that distinction. The chain proves that what was recorded and sealed has not been altered since. It does not prove completeness: deleting a maintenance job or a reading is not itself recorded today, so a clean chain means 'nothing recorded was changed', not 'nothing happened that went unrecorded'. Editing is traced; removal is not.

How does an auditor verify a checkpoint?

A checkpoint is a fingerprint plus an entry count, published where anyone can read it. If the records shown during an audit still produce that fingerprint, they are the same records that existed when the checkpoint was published. If a single character changed, the fingerprint will not match.

Does it work offline?

Work done at sea is queued in the offline outbox with its original timestamp and syncs when a link appears. Sealing happens after sync: records you seal yourself carry the moment you sealed them from the ledger console, and change history is sealed automatically approximately hourly at 25 minutes past the hour, with a published checkpoint produced daily at approximately 02:35 UTC — so the fingerprint carries the time it was sealed rather than the time the work was done.