Shipwrecks


Anchors

wooden-stocked anchor
An old-style wooden-stocked anchor stowed alongside on a sailing ship. Note the two hawsepipes where the mooring chains enter the bow.

Not all artifacts are easily recoverable. Ship's anchors often weigh in the hundreds or thousands of pounds and require a well-planned expedition to bring back to shore. At right is an assortment of anchors, from the old-fashioned "Fisherman's" anchor of the 1800s to the modern stockless or "naval" anchor, and its small cousin, the Danforth anchor.


Wooden Ship Framing
Wooden Ship Framing

Wooden ships have been constructed for thousands of years. Around the world, many different construction techniques have been used, some of them quite extraordinary. The ancient Greeks stitched the planks of their warships together edgewise to form an extremely light frameless load-bearing shell, much like a modern airplane fuselage. However, most wooden ships are built using a basic framing system that has changed little over the centuries.


paddlewheel

The paddlewheel predates even the steam engine. Horse-driven paddlewheel ferries have been in use for hundreds of years. Compared to screw-type propellers, the design and construction of a paddlewheel is much simpler, and therefore they remained the dominant method of propulsion through the mid-1800s, with some examples remaining in use until after World War II.



steam-powered winch
A steam-powered winch on a schooner barge. Note the various drums for drawing up anchor chain, towing hawsers, etc, and the anchor chains themselves going down through the deck into the chain locker below.

Prior to steam power, the only force available on a sailing ship to perform all the necessary work was the men on board. For some tasks, such as raising the anchor, it might be necessary to yoke the entire crew to a multi-deck manual capstan. On the largest vessels, even with every available man, this might take several hours to complete. With the advent of steam power, a "donkey engine" and a single engineer could do the work of many men, in less time, and these were soon installed in almost all vessels.


Scotch boiler ( cutaway )
A typical Scotch boiler ( cutaway )

Boilers are one of the most common shipwreck features, found on almost all engine-powered vessels. The purpose of a boiler is to produce high-pressure steam for the engine to propel the vessel. Steam boilers have been in use from the early 1800s to the present day.


Shipwreck Essex
Type:
shipwreck, steamer
Built:
1890, Philadelphia PA USA
Specs:
( 272 x 40 ft ) 3018 tons
Sunk:
Thursday September 25, 1941
ran aground on Block Island - no casualties
Depth:
30 ft

Printed from njscuba.net