"Mālama pono" - This is a general well-wishing phrase meaning "take care" or "be well," and can be used to wish someone a safe journey.
"E ola i ka makani" - This means "May you live with the wind," wishing for favorable winds.
"E ola i ka moana" - This means "May you live with the ocean," wishing for safe passage through the sea.
"E ola i ka holo" - This means "May you live with the journey," wishing for a smooth and successful trip.
You can combine any of these phrases, like "Mālama pono, e ola i ka makani a me ka moana." This would translate to "Take care, may you live with the wind and the ocean."
Important note: While these phrases capture the essence of "fair winds and following seas," remember that Hawaiian language is full of nuances and subtleties. Using these phrases respectfully and understanding the context is important.