Does The Sailor's Knife work offline?
Yes. The Sailor's Knife is a single HTML file that runs entirely in your browser. No internet connection required after download. Your data never leaves your device.
\
The Sailor's Knife
Eight nautical tools plus emergency MOB — works without shore power
Maritime & NavigationKnife 24 of 50
$39
One-time purchase · Instant download30-day money-back guarantee
$39
What it does
The Sailor's Knife v2.0 gives mariners eight practical tools and an emergency system in a single HTML file. Convert nautical units, reference the Beaufort wind scale with sea state descriptions, calculate tide heights using the rule of twelfths, compute compass corrections for variation and deviation, browse knot guides by category, reference IALA Region A and B buoyage systems, plot dead reckoning legs with leeway and tidal set on a dynamic chart, and check sunrise, sunset, twilight times, and moon phase for any date and position. The MOB button instantly logs your position and starts a timer. Everything works completely offline — perfect for passages, anchorages, and ocean crossings.
LIVE DEMO — TRY IT NOW
Demo unavailable. Please try again later.
INCLUDED TOOLS — 8 TOTAL
\Nautical Unit Converter
\Beaufort Scale Reference
\Tide Calculator
\Compass Deviation Calculator
\Knot Reference Guide
\Buoyage System Reference
USE CASE 01\Caribbean Trade Wind Passage
\DR Plot
\Astro Almanac
USE CASE 02\English Channel Crossing
USE CASE 03\Norwegian Fjord Navigation
USE CASE 04\Offshore Emergency Response
USER'S GUIDE
Download PDFFull documentation with detailed instructions for every tool.
DELIVERYSingle HTML fileDownload instantly after purchase
PRIVACY100% localYour data never leaves your machine
OWNERSHIPOne-time purchaseNo subscription, no recurring fees
PRO TIP
The file works in any modern browser — Chrome, Firefox, Safari, Edge. Save it to a USB drive, email it to yourself, or keep it in your cloud storage. It will work anywhere, anytime, forever.
Sovereignty as a Service
$39. Yours. Forever.
EXPLORE THE SAILOR'S KNIFE
By Profession
By Use Case
Problems This Solves
FREQUENTLY ASKED QUESTIONS
OTHER PRODUCTSIs The Sailor's Knife a subscription?
No. The Sailor's Knife is a one-time purchase of $39. No monthly fees, no renewals, no price increases.
What is included in The Sailor's Knife?
The Sailor's Knife bundles 8 maritime & navigation tools into a single HTML file: Nautical Unit Converter, Beaufort Scale Reference, Tide Calculator, Compass Deviation Calculator, Knot Reference Guide, Buoyage System Reference, and 2 more.
Where is my data stored?
Entirely in your browser's local storage. Nothing is uploaded, transmitted, or tracked. You can export your data as JSON at any time and import it on another device.
Which browsers and operating systems does The Sailor's Knife support?
Any modern browser — Chrome, Firefox, Safari, Edge — on Windows, macOS, Linux, ChromeOS, iOS, or Android. The same file works everywhere.
Can I try The Sailor's Knife before buying?
Yes. The interactive demo on this page is the full knife running in an iframe. Try every feature in your browser, no signup required.
Sovereignty as a Service