Loud horn blasts are heard outside Jupiter’s anchorage near the Gordon Channel where massive cruise ships steam southbound from Alaska. We track the ships’ electronic signatures live on our chartplotters, but see nothing of them as they transpass in heavy fog.

Captains follow the convention described in the International Regulations for Preventing Collisions at Sea (COLREGS) Rule 35, Sound Signals in Restricted Visibility: A power-driven vessel making way through the water shall sound at intervals of not more than 2 minutes one prolonged blast.

Celebrity Obsession, Disney Sorcery and Arctic Magnet, each in turn, audition a thundering basso profundo as they travel sightless and unseen. Our double blind choice is unanimous: Arctic Magnet speaks strongest and longest.

Advection sea fog occurs when moist air moves over colder water, cooling the air to the dew point, and August often carries this condition into our summer cruising grounds. Local boaters have renamed June Junuary for the predictable relapse into cold, rainy weather, and Faugust follows July.

It is one of many recent foggy days and Jupiter’s gravy-eyed crew sees nothing further than 500 feet during the entire days travel. It is clear under blue skies where Jupiter now lays, but outside at every azimuth restless banks and boas of glaucous mist tease vision from anxious seafarers.

Marine fog often lies horizontally in a layer so thin that the helmsman can look upwards to blue sky and sunshine casts shadows across the foredeck, but ahead and outward nothing at all. Jupiter glides into misty opaque bands lain athwart her heading before reemerging into fulgid seascapes.

After gazing endlessly into opacity, it is difficult to judge scale and distance, as though the mind has given up knowing what to expect with no episteme.

Helmsmen learn to pilot on instruments, chartplotting and radar tracing competing with the timely need to peer myopically ahead into the grey miasma scouting for logs eager to hole the boat, disable the running gear, or worse.

Fog may dissipate at sunrise, after breakfast, lunch or not at all. Waiting sometimes works out, but if a timed tidal passage or long voyage is needed Jupiter is underway in many weathers.

Contemporary electronics make low visibility passages possible, but retaining situational awareness requires discipline and all hands crosscheck. It is compelling, challenging and hauntingly beautiful.

In Maine it is said: If you do not go in fog, you do not go at all. The same might be concluded for British Columbia in August.

When a serene sea beckons, Jupiter rounds Cape Caution, southbound, along with other vessels large and small, without seeing them, cape or continent at all.