Shipstern Bluff Swell Window
Tasmania, Australia · part of the Shipstern Bluff spot guide
- Swell window (from)
- 140°–250° (SE–WSW)
- Best direction
- ~205° (SSW)
- Period sweet spot
- 14–18 s
- Open-ocean height (Hs)
- 8–26 ft
- Resulting faces
- 6–30 ft
Open-ocean vs. the face: the heights on buoys and forecast models are significant wave height (Hs) in deep water. What you ride is the breaking face, which depends on period, direction and this break's bathymetry — that's why the two rows above differ. PierMonkey's spot ratings already do this conversion for you.
The window runs from south-southeast through south to southwest, best in the south-southwest band around 200–225° as swell funnels up the edge of Tasmania to hit the reef nearly head-on. Long period is essential — roughly 14-to-18 seconds and up — because it draws the most water off the reef and builds the step; short-period wind swell does not produce the marquee wave.
The reef amplifies dramatically once over threshold, so the breaking face climbs far faster than the open-ocean height: below about a metre it barely breaks as a slab, a metre-plus at long period gives 6-to-8-foot faces, and three metres and up produces 20-to-30-foot faces. Read the alert threshold as open-ocean height, never the face.