Latham & Matthews put this “in the mouth of the Thames c. 10 miles north-west of the Foreland”. This map makes it look perhaps further out, and its location is used for the map shown here.
The overlays that highlight 17th century London features are approximate and derived from Wenceslaus Hollar’s maps:
Open location in Google Maps: 51.788232, 2.076416
The Galloper is a sandbank, around 50 km offshore from the Felixstowe area, around 11.5 km long and less than 1 km wide. The general depth of the area is 30-50 m to the west and 20-30 m to the east. However the depth over the Galloper itself decreases from 20 m to as little as 2 m. The geology is predominantly gravel and sand over the London Clay. The tidal range in the character area is within the range of 3-4 m at Mean Spring Tide (DTI 2004).
As a result of its proximity to the ports of Harwich and Felixstowe the northern half of the area comes within the jurisdiction of the Harwich regulatory system. It is subject to restrictions concerned with high speed craft, submarine cables and traffic separation and is covered by Vessel Traffic Services (VTS). The southern half of the area does not fall under the jurisdiction of Harwich but is subject to restrictions concerned with high speed craft, submarine cables, changing depths and draught restrictions. A submarine network cable runs north-south through the area connecting the United States with the UK, Germany and the Netherlands.
The Galloper sandbank is avoided by shipping. The area has potential to contain submerged prehistoric landscapes, features or artifacts, having been dry land prior to 8000 BP. However, no investigation work is known to have been done in this area.
In 2007 planning consent was given to Greater Gabbard Offshore Winds Ltd for the construction of a windfarm comprising 140 turbines over two sites. The larger site covers much of the Galloper sandbanks, the second site is on the Gabbard sandbanks. Overall the area is expected to produce 500 MW of energy - enough to power 415,000 homes, more than the domestic demands of Suffolk.
For more info, see https://archaeologydataservice.ac.uk/archives/vie…
Chart showing the number of references in each month of the diary’s entries.