In 1980, Bob Ward visited every inlet on the Washington and Oregon Coasts, armed with copies of the two contemporary maps. There is only one inlet that matches the two maps: Whale Cove, which lies at 44° 47’ on the Oregon coast, just south of Depoe Bay and north of Cape Foulweather. When he examined the Cove, he understood the secret of the Hondius Inset.
Whale Cove is protected by a spit, made out of hard volcanic basalt. Across the neck of the spit is a fissure, through which the ocean flows at high tide while also covering the low lying rocks, and turning the spit into an island. Maps of Whale Cove sometimes show a spit because the map was drawn from an aerial photograph taken at low tide, and sometimes show an island, because the base photograph was taken at high tide. When Drake found Whale Cove, the original artist drew the shape of the harbor at low tide, perhaps from the crow’s nest, as he waited while soundings were taken to make sure the Cove was deep enough for the Golden Hinde. Then as they sailed in on the high tide, he noticed that the spit was now an island. He drew its new shape, placing it alongside the spit in his sketch, as a personal "aide-
Below is an alternative illustration of high and low tide versions of the Hondius inset sketch.