Navigare necesse est

Shipping, Yachting and Merchant Marine

Maritime navigation, nautical culture and law of the sea

Navigare Necesse Est brings together a vast collection of documents dedicated to maritime navigation, the law of the sea, nautical history and seafaring culture. The website provides access to several decades of research, teaching and technical reflections written by P.-A. Reymond, former merchant navy officer, naval architect and specialist in pleasure boating navigation.

The publications cover offshore, astronomical and coastal navigation, nautical instruments, international maritime regulations, naval architecture, maritime traditions, exploration history, maritime safety and contemporary developments in maritime law.

A comprehensive and independent maritime resource

The website is intended for professional sailors, pleasure boaters, students, maritime history enthusiasts, naval model makers, teachers and anyone wishing to better understand the maritime world and how it functions.

You will find content dedicated to:

  • astronomical navigation and nautical calculations
  • nautical charts and navigation instruments
  • compasses, chronometers, sextants and sundials
  • RIPAM / COLREG and maritime regulations
  • territorial waters, EEZs and international conventions
  • ship stability and maritime safety
  • merchant navy and the Swiss merchant marine
  • nautical traditions and maritime culture
  • Vikings, maritime explorations and sea routes
  • naval architecture and yacht construction techniques
  • astronomical phenomena useful for navigation
  • ancient units of measurement and maritime scientific history
  • traditional Lake Geneva boats and nautical heritage

Technical and historical documents accessible to everyone

The texts gathered here were written throughout a career devoted to the sea, navigation and the transmission of nautical knowledge. Some documents are highly technical, others more historical or cultural, but all aim to make knowledge accessible in a clear and concise manner.

The website promotes an independent and well-documented approach based on practical experience, maritime practice and technical popularization.

A living maritime heritage

Beyond the technical aspects, Navigare Necesse Est also seeks to preserve and transmit a maritime heritage that is often overlooked: navigation traditions, nautical vocabulary, historical accounts, ancient methods, forgotten instruments and maritime know-how.

In a world where digital technologies are profoundly transforming navigation, this knowledge remains valuable for understanding maritime history, nautical practices and the foundations of modern navigation.

Multilingual publications

Most documents are available in French, with some also translated into German, English, Italian or Spanish. As translation work is still ongoing, any help or contribution is welcome.

Fair winds and happy reading.


Should you not find the document that interests you in your own language, you can always read it in French, and also sometimes in another language.

Until now, not all pages have been translated into D, GB, E and I. If you wish to help us with this task, we welcome your contribution. Contact us.

Navigare Necessse Est brings together a wide collection of documents dedicated to maritime navigation, navigational astronomy, the law of the sea, nautical history, naval technology, maritime traditions and seafaring culture.

The website offers educational, technical, historical and cultural content intended for sailors, navigation enthusiasts, students and anyone interested in the maritime world.