Switching guides

Hours of Rest without
the sales call.

ISF Watchkeeper is the Hours of Rest software crews inherit. It was built for commercial shipping fleets, and it is bought like it. There is no price on the site. You email sales and wait for a quote.

Two ways to keep the same record.

How it is boughtWatchkeeper is licensed per vessel on a quote. It grew up as Windows desktop software for cargo fleets, and there is a mobile version now, sold the same quote-only way. The Muster App has its price on the pricing page and a 14-day trial you start yourself.
Where the day gets loggedCrew log rest on their own phones. Hours of Rest are computed on the phone itself, so a crew member logs the day and sees the verdict with no connection at all.
What a breach looks likeCross an MLC limit and the rule is named on the spot. A non-compliant day cannot be saved until a comment explains it, and the crew member, their HoD and the Captain settle it in one thread.

Checked against MLC 2006 as it is entered.

10 hours in any 24

Checked against every 24-hour window the day’s work opens or completes, not just the midnight-to-midnight day.

77 hours in any 7 days

A rolling week, looking back from each day’s work. Every rest period counts toward this one.

The two-period rule

When rest is recorded in more than two periods, only the two longest count toward the 10 hours, and one of them must be at least six hours.

Every logged day comes back rested, borderline or non-conformity. The rules themselves are set out in the Hours of Rest guides, and you can check a day on the Hours of Rest calculator.

The monthly sheet, signed and kept for inspection.

One row per day, half-hour columns, daily rest totals, and the rolling 24-hour and 7-day minima. Comments print on their own sheet.

At sign-off the PDF is stored for inspection and a copy is emailed to the seafarer. How hours of rest works

MLC hours of rest is part of Plus: £175 a month per vessel, unlimited crew. Information correct on 23 August 2026, as per the official website of the service named: ISF Watchkeeper products.

Related pages

The real cost of separate apps

The arithmetic, side by side.

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