For those not yet familiar with the waters at the Northern end of Vancouver Island, Nahwitti Bar is an underwater shelf that rises from the depths of the Pacific Ocean, beneath Goletas Channel. As a west facing bar it generally protects Pacific Ocean high seas rising in the Goletas Channel during west gales. Crossing this bar is one of the many challenges faced by mariners navigating the waters around the Island.
Information excerpted from
Sailing Directions PAC202 Department Fisheries and Oceans, Canada
"Tidal Streams in the Goletas Channel and across Nahwitti Bar set east on the flood and west on the ebb. In the east part of Goletas Channel, tidal streams do not exceed 3 kn but at the west end, in vicinity of Nahwitti Bar they sometimes attain 5.5 kn.
Nahwitti Bar extends from the west end of Hope Island across the west entrance to Goletas Channel. Tatnall Reefs on the south part of Nahwitti Bar extend NW from Vancouver Island. The fairway north of Tatnall Reef is about 0.8 mile wide with depths of 11 m. Depths on the seaward side of the bar increase very gradually. On the inside of the passage they increase suddenly to about 72 m. A swell is nearly always present on the bar. In bad weather with a west wind opposing a strong west-going tidal stream there is a very heavy sea on the bar that breaks and is dangerous to small vessels. In strong west gales, the sea breaks across the bar and it is dangerous to attempt crossing the bar.
Tidal streams set fairly across the Nahwitti bBar in the direction of the channel and attain 5.5 kn The flood sets east the ebb sets west. The duration of the HW and LW slack is about 12 and 17 minutes, respectively.
Heavy rips and overfalls are formed when the tidal stream is opposed by strong winds. These rips and overfalls can be dangerous to small craft. The best time to cross the bar is at or near slack water.
It is reported that small vessels can avoid crossing the Nahwitti Bar by passing south of the Tatnall Reefs and following the Vancouver Island shore. Weser Island can be then passed on either the north or south side. Shelter can be found in the bay on the east side of Cape Sutil if required."