Underwater excavation is called dredging. A dredge is a machine that scoops or suctions sediment from the bottom of the waterways or is used to mine materials underwater. While the instrumentation of modern dredges is computer assisted, the basic excavation methods of dredges have remained the same since the late 1800s. The two main types of dredges Local 25 members work aboard are mechanical dredges and hydrhydraulic dredges.A suction hose does just that, it’s a pump, pulls, vacuums, or sucks the material or liquid through the hose. They can also be referred to as Delivery Hoses. Typically, suction hoses can be used for both suction and discharge. Each hose is different, double-check with Atlanta Rubber & Hydraulics if you are unsure or if you are considering a specialty hose.

Suction hoses are constructed to maintain their round shape and not collapse when used under the hose’s normal use. Note that using a hose other than its unintended use will damage the hose.Fenders are buffers between vessels and the wharf. The principal function of a fendering system is to provide protection for both wharf and vessel by absorbing the vessel's berthing energy thus reducing the forces on both the wharf structure and vessel. The used of fender allow a reduction of wharf construction costs and provides ship owners with a satisfactory system for ship protection.Industrial chains consist of linked segments of durable metal, such as stainless steel, galvanized steel, and brass. They are available in a wide range of sizes and strengths to lift and transport materials across a diverse set of applications.

The tensile strength of the base material—i.e., the ultimate breaking strength—determines the rating and grade given to the particular chain. The greater the breaking strength, the higher the grade, and vice versa. The grade indicated for a chain helps industry professionals identify the types of applications for which it is appropriate. For example, the strength of galvanized chains relies on the amount of carbon present in the metal; as grade 30 chain has less carbon, it is weaker than grade 40 chain and suitable for service duty applications rather than heavy-duty applications.

A mooring system is made up of a mooring line, anchor and connectors, and is used for station keeping of a ship or floating platform in all water depths. A mooring line connects an anchor on the seafloor to a floating structure. We will focus on mooring Mobile Offshore Drilling Units and Floating Production Systems.

The mooring line can be made up of synthetic fiber rope, wire and chain or a combination of the three. Environmental factors - wind, waves and currents - determine which materials make up the mooring system.