Deadeyes & Blocks

deadeye
deadeye

Deadeyes (above and right) and blocks (below) were used in the rigging of old-time sailing ships. In either case, the purpose was to gain mechanical advantage through the use of compound pulleys. This was especially necessary in the days before powered winches, when the only working force onboard was literally manpower.

deadeye

Deadeyes were used mainly in static rigging, such as mast stays. Although there are no moving parts, a deadeye still functions as a pulley, albeit with greater friction. The name deadeye is thought to come from the resemblance to the eyes of a skull. Deadeyes were always used in pairs as shown, although they are usually found singly, the lanyard between having long since rotted away.

block

A block really is a pulley, with one or more rollers to decrease friction. Blocks were used in live rigging, such as for trimming sails. Pairs of double or triple blocks ( with multiple rollers on a common axle ) could accomplish the same mechanical advantage as a deadeye. Modern sailboats still use such arrangements, often with built-in ratchets.

Before the advent of high-strength steels, blocks and deadeyes were constructed from very dense, tough woods, such as elm or lignum vitae. As a result, these articles often survive well in the sea and may be recovered by divers in relatively good condition.

In the latter part of the nineteenth century, wooden deadeyes and rope stays were replaced by metal turnbuckles and steel wire, while multiple blocks were replaced by steam-powered winches, which could function without the need of force-multiplying pulleys. Therefore, finding a wooden deadeye or block is a good indication of the age of a wreck.

rigging
The sails and rigging of a square-rigged sailing ship - the Charles W. Morgan. There are literally hundreds of lines, as sailors call them; 'ropes' to the rest of us.
rigging

Detail of the standing rigging of the mainmast of the Charles W. Morgan, showing the stays and deadeyes. Some of the running rigging is also shown, with blocks and pulleys. It is impossible to depict these details at the level of resolution of a computer monitor. Go and see the ship for yourself at Mystic Connecticut.

rigging
rigging
The complexity of a large sailing ship
rigging
block
Captain Ed Febo with a double block recovered from the Sea Girt wreck.
block
Both the frame and the rollers are wood.
deadeye
Deadeyes recovered from a schooner wreck. These are lower ends, that would be attached to the hull by shackles.
deadeye
This is the upper end of a deadeye, upside-down, with strapping still attached. The strapping is wire cable, wrapped in manila cord and tarred canvas strips; only the "deadeye" itself is wood.

Gammarus

Amphipod crustaceans typically range in size from 2 to 50 mm, although a few may be larger. Amphipods are common in aquatic ecosystems throughout many parts of the world, inhabiting marine, brackish, and freshwater environments. A few species are also terrestrial. Amphipod means "different foot", a reference to the varied legs that are evident in the illustrations, as opposed to isopods.

The order Amphipoda, which contains nearly 7,000 described species, is divided into three suborders: Gammaridea, Caprellidea, and Hyperiidea. Gammaridea, with more than 5500 described species, is not only the largest amphipod suborder but also contains all of the freshwater and subterranean taxa. Approximately 21 superfamily groups, 95 families and more than 1000 genera are recognized within this suborder.

Printed from njscuba.net