Feasibility Of a Lightweight Buoy Mooring Concept

Abstract

Abstract This paper describes the feasibility analysis and field test of a novel buoy mooring concept.* Successful field tests on the Severn River near Annapolis, Maryland, indicate that the concept is ready for engineering development. The technique allows for repeated latching to and release from a bottom emplaced anchoring station. Means are provided for relocating the bottom anchoring station, which may be very accurately positioned at initial emplacement. Thus, the need for resetting heavy anchors every time a lightweight buoy must be restationed can be eliminated. Introduction A major concern of those who use the waterways for travel and commerce is accurate knowledge of local bottom topography. This concern is seen in the duties of the sounding man made famous by Mark Twain and other writers. Indeed, Samuel Clemens adopted the call of the Mississippi river pilots "Mark Twain", indicating a depth sounding of two fathoms, as a pseudonym for his novels of river life. Aids to navigation can be considered as the traffic signs of waterways. They serve to channel traffic, warn of danger, and alert mariners to their location. The United States Coast Guard is responsible for the accurate deployment and maintenance of buoys in our nation's navigable rivers, lakes, and coastal waters. In certain areas, particularly the Great Lakes, this responsibility necessitates the annual deployment and retrieval of these buoys together with their mooring chains and concrete block anchors. The mass retrieval of these buoys is a preventive measure to protect the buoys from ice damage in the winter months. This repetitive operation involves excessive ship operational time as well as the gross expenditure of materials and labor. Present technology has advanced to enable the development of lightweight buoys. These can be constructed of such advanced materials as sandwich cores, glass-reinforced plastics, or composites, and can reduce the arduous task of buoy deployment. In fact, the lightweight buoy would lend itself to deployment from a small tender or buoy boat. The problem still exists, however, of handling the 2000-lb, or greater, anchor that must be annually deployed and retrieved from rather sizable vessels. A requirement exists for a device or system that can accomplish repetitive mooring of lightweight buoys in water of less than 100-ft depth. Such a system must be inexpensive, simple to operate, reliable, and deployable with high accuracy in repetitive moorings. Introduction (Continued) The Coast Guard does not necessarily have to identify every natural or manmade hazard. However, when they do mark such hazards in the interest of safety to navigation, they must do so accurately and competently. This fact has been seen in such litigation as SOMERSET SEAFOOD COMPANY versus the UNITED STATES (193F. 2d 631, 1952) where the responsibility of accurately stationing buoys was clearly established. In this case, a commercial vessel was sunk by a submerged wreck which was marked by an adjacent Coast Guard buoy.