The next leg from Wick to Kirkwall in Orkney required careful preparation, because we needed to cross close to the Eastern end of the notorious Pentland Firth.
This has ferocious tides but, more seriously, is peppered with rocks and deep underwater reefs that create enormous turbulence. Ships, even the navy, are wary of the Firth. In some conditions it can be deadly for small craft.
tide by tide 