The "Southwest Mohawk" or "Coffee Wreck" is nothing like its namesake. Artifacts found on the wreck indicated that it was a late eighteenth-century sailing ship and not a barge.
Building artificial reefs is a lot more than just throwing junk in the ocean. The material needs to meet standards for cleanness and suitability, and it needs to end up where it is intended, and not somewhere else. Concrete and stone are easy, as they go straight down wherever they are dropped.
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.
Steam engines are a common sight on New Jersey shipwrecks. Usually the highest point of relief on the entire wreck, the engine makes a good orientation point and is often used as a tie-in as well. Old steam engines were quite sturdily constructed, and last a long time in the ocean, although because of their value they were salvaged when possible.
Right: The single-expansion steam engine of the Delaware, viewed over the top of one of the four boilers.
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.
Iron and steel began to replace wood in ship construction in the middle to late 1800s. Timber-poor Europe ( especially England ) led in the development of iron ships, while America, with its vast reserves of lumber, continued to build wooden ships for some time longer. However, as the economical size of ships grew to surpass what could be built of wood, America too began constructing iron ships. For a few years, composite ships were built with iron frames and wooden skins, as seen at right, but difficulties with corrosion between the wood and metal soon led to hulls built completely of metal, both sailing ships and steamers.
In this modern age of radio, these signal flags are a quaint anachronism that is no longer used, although they were once very important in ship-to-shore and ship-to-ship communications. Each flag stands for both a letter value and a shorthand message. The letters are expressed here in the modern international phonetic alphabet, in which A-B-C would be spoken Alpha-Bravo-Charlie (see below).