From "The Big Anchor Project":
"16th-17th century anchors
The earliest drawings of an anchor with details of its weight and dimensions appears in “Fragments of Ancient Shipwrightry” attributed to Matthew Baker, dated to the late 16th or early 17th Century.
Most anchors during this period had curved arms, but as larger anchors were required the straight arm anchor was introduced to English vessels. The flukes were generally the shape of equilateral triangles and half the length of the arms. The anchor ring was slightly smaller diameter than the fluke. The anchor stock was roughly the same length as the shank, made from timbers bound with iron hoops. Wooden pegs or treenails were used to secure the timbers in the stock, which was straight on the top and tapered on the other three sides.
In 1627 Captain John Smith published “A Sea Grammer" which provided a list of the different types of anchors carried by ships at that time. It listed:
•The kedger anchor - the smallest of the anchors used in calm weather
•The stream anchor – only a little larger used in an easy tide/stream
•The bow anchor – larger - 4 in total
•The sheet anchor – the largest and heaviest of all used in emergencies.
Anchor weight was in proportion to the size of the ship. A ship of 500 tons would have a sheet anchor weight 2000 pounds of 907 kg’s."
Chart showing the number of references in each month of the diary’s entries.