When going through the islands just north of Desolation Sound, you encounter several sets of tidal rapids that must be passed near slack water. At full surge, some of the rapids roar with power that would overwhelm most any boat. Sue read the tide/current tables and determined when we needed to pass Dent Rapids and Yaculta Rapids. Different sections of the approach and the exit are at different times than the advertised ones. So we saw as much as 5.5-9.5+ Speed Over Ground at various points. Once through the rapids it was a cake walk to our next anchorage at Van Donup Inlet.