Famous Maritime Passages — Alaska & Hawaiʻi

The Inside Passage runs from Puget Sound, Washington to Skagway, Alaska — threading 1,100 nautical miles through a labyrinth of islands, fjords, and tidal channels. Tidal range in southern SE Alaska reaches 14–18 ft; currents through narrow passages like Wrangell Narrows require careful timing. The passage is famous for its whale density, especially humpbacks feeding on herring near Frederick Sound. Prince of Wales Island offers some of the most remote anchorages in North America.

Prince William Sound is a semi-enclosed sea ringed by the Chugach Mountains and home to dozens of tidewater glaciers. Whittier connects to Anchorage via the Anton Anderson Tunnel. Valdez sits at the head of Valdez Arm and marks the terminus of the Trans-Alaska Pipeline. The sound sees strong williwaw gusts — localized outflow winds that accelerate down glacier valleys with no warning. Monitor Kilo's real-time wind from buoy 46060 (SW PWS) and anemometers at Whittier and Cordova.

Cook Inlet is home to the second-largest tidal range in North America — Anchorage regularly sees 35–38 ft tides on spring cycles. The upper inlet has dangerous glacially-silted mudflats that look like beaches but act as quicksand. The bore tide at Turnagain Arm is a genuine tidal bore — a 6–10 ft wall of water advancing at 10–15 knots that can be surfed by experienced kayakers at the right anchorages. Tidal currents in the mid-inlet run 5–8 knots and must be factored into passage planning.

Shelikof Strait — separating Kodiak Island from the Alaska Peninsula — is one of the most meteorologically intense waterways in Alaska. Cold outflow from the Alaska Range collides with Gulf of Alaska moisture to produce violent williwaw squalls. Sustained 60-knot winds with minimal warning are documented multiple times per year. The strait has no useful harbors for 40+ nautical miles in certain sections. Passage should only be attempted by experienced offshore mariners with fully equipped vessels. The reward is access to world-class halibut grounds and the remote beauty of Katmai.

Chatham Strait is a 150-mile north-south channel between Admiralty Island and Baranof/Chichagof Islands — one of Alaska's deepest inland waterways at over 2,000 ft. It serves as a major migration corridor for humpback whales in late summer. The strait channels northwesterly winds and can produce steep short-period chop. Tenakee Springs, a tiny village with a public bathhouse, is a popular stop for cruising boats. The northern exit at Cross Sound is exposed to Pacific swells from the west and can be rough in any westerly wind.

Kenai Fjords National Park protects 669,984 acres of coastline carved by the Harding Icefield — one of the largest non-polar icefields in North America. Seward is the gateway: a 4-hour drive from Anchorage. The outer coast faces unobstructed Pacific swells and is passable only in settled weather. Tidewater glaciers calve constantly — ice chunks can be football-field sized and roll unpredictably. Resurrection Bay provides a sheltered corridor south of Seward for the first 15 nautical miles before the coast opens to the Gulf.

The Aleutian chain stretches 1,200 nautical miles from the Alaska Peninsula to Attu, the westernmost point in North America. Unimak Pass — the widest and safest passage between the Pacific and Bering Sea — processes a large fraction of trans-Pacific shipping. The Aleutians are famous for catastrophic weather: williwaw winds exceeding 80 knots, horizontal rain, and multi-week fog are all documented. Passage by recreational vessels is an expedition undertaking requiring AIS, SSB/INMARSAT comms, liferafts, and EPIRB. The fishing, however, is unparalleled.

The Kaiwi Channel — colloquially 'the channel of bones' — is the 26-nautical-mile stretch of open ocean between Maui Nui and Oahu. It is the venue for the Molokai Hoe outrigger canoe world championship each October and the legendary Molokai-2-Oahu paddleboard race. Northeasterly tradewinds funnel through the channel, frequently building 15–25 knot winds and 8–12 ft combined seas. Even experienced captains plan crossings for 4–6 AM departures when trades are lightest. Current can set vessels 2–3 nm west of track.

The ʻAlenuihāhā Channel separates the south coast of East Maui from the Kohala and Kona coasts of the Big Island. Its 30-nautical-mile width is channeled by the massive volcano slopes of Haleakala and Mauna Kea, which accelerate the northeast trades to 30–50 knots on bad days. The channel is notorious among inter-island sailors: published wind averages understate conditions significantly because the wind gradient from calm-on-Kona to howling-midchannel happens within a few miles. Most sailboats plan north-to-south (Maui to Big Island) downwind passages. Return trips require careful weather windows.

At 70 nautical miles, the Kauai Channel is the longest inter-island passage in Hawaii. Most boats depart Nawiliwili (Kauai) at midnight to arrive at Honolulu with morning light — a 12–15 hour overnight sail. Kauai sits at the northwestern end of the main Hawaiian Island chain, directly in the path of northeast trades and North Pacific groundswell. The Na Pali Coast on Kauai's northwest shore is accessible only by sea in summer and is one of the most dramatic coastlines in the Pacific.

The Pailolo Channel between North Maui and Molokai is only 10 nautical miles wide but is among the most important humpback whale habitats on Earth. The warm shallow waters of the AuAu Channel and surrounding Maui Nui waters host the vast majority of the North Pacific humpback population each winter. Federal law requires vessels to maintain 100 yards from whales; approaching closer is a federal violation. The channel sees heavy whale concentration January through March. NOAA's Hawaiʻi humpback whale sanctuary rules are enforced by USCG District 14.