T&R Bulletin 2-15 (1967) supersedes the existing T&R Bulletin 2-5 (1959) and T&R Bulletin 2-7 (1962).
Over a period of years, Task Group HS-6-1 (Aluminum) of The Society of Naval Architects and Marine Engineers Technical and Research Program has noted the increasing use of wrought aluminum on ships and has therefore endeavored to disseminate information on various facets of its application. This group was assigned the task of evaluating the available alloys, sizes, and shapes of wrought aluminum suitable for shipbuilding and other marine applications. The results of this work are summarized in this publication which is an effort to provide a ship designer and builder in the Americas with a convenient guide. It does not include European practice.
Three Canadian and one United States Great Lake ore carriers were instrumented to measure wave or otherwise induced hull stresses and an extensive system for obtaining wave and sea state records from remote wave recording buoys (both moored and ship launched), wave staffs and gages, ship observations, weather stations, etc. was established. The basic wave data obtained in 1965, 1966 and 1967 in Lake Superior and the Gulf of St. Lawrence is presented in this report. Waves were recorded at fourteen locations and a total of approximately 18, 000 usable wave records were collected.: The analyzed results are presented in various forms, but it .was felt that most naval architects and scientists would only require the original wave data. The details of the manipulation of the data to obtain estimates of the probabilities of occurrence of wave heights and wave frequencies have therefore not been included.
The data presented in these two bulletins have been analyzed and the results and various interpretations presented in a series of papers on July 21, 22 and 23, 1971 published as T & R Symposium Report No. S-2 "Hull Stresses in Bulk Carriers in the Great Lakes and Gulf of St. Lawrence Wave Environment."
Current economic considerations indicate a need for more competitive ships to transport all types of cargoes at a lower cost per-ton-mile than has previously been possible. The dissemination of useful information on the application and use of higher-strength steels in shipbuilding is one means of fulfilling this need. This monograph explores the current design, fabrication, and economic problems associated with the application of higher-strength steels in the major components of the hull structure of merchant ships. Various classification societies' current rules and guidelines are discussed; comments are offered on advantageous ship proportions and certain areas of caution for designers and shipbuilders are defined.
Describes and tabulates general characteristics of available low alloy and high strength steels for use in construction of commercial ships and offshore structures. Includes three ranges of marine higher strength steels, as well as fracture tough, low temperature and cryogenic, abrasion resistant, corrosion resistant and elevated temperature applications. Extensive bibliography provided.
This Bulletin describes two methods for designing the fire protection of aluminum structure in ships, the traditional "A", "B", "C" Class system, and a new approach which bases protection on the fire exposure.
The Bulletin is based on a series of fire tests conducted at the National Bureau of Standards from 1968 to 1970. These tests established the amount of insulation needed to protect the aluminum structure for various lengths of time under a standard fire exposure. They showed that insulation on the fire exposed side of the structure is necessary to prevent melting or weakening of the aluminum, but that insulation on the unexposed side is harmful because it raises the temperature of the metal. The results of these tests have been used to develop formulas, tables, sketches, and sample calculations which are included to make the bulletin a working tool in the design of the shipboard aluminum structure.
Several aspects of the design and behavior of ship stiffened plates are discussed in this bulletin.The stiffened plate which is represented by an equivalent orthotropic plate, is subjected to compressive in-plane edge loads in two perpendicular directions, in-plane edge shear and lateral load. The basic differential equations describing the behavior of the plate in the prebuckling as well as in the postbuckling regions are presented, and a computerized solution is given. Non-dimensional design charts are presented giving the center deflection, critical load, effective width and bending moment in the stiffened plating. The charts are generated to cover a wide variety of values of the biaxial in-plane compressive loads, the in-plane shear, the lateral load, the virtual aspect ratio and the stiffeners and plate geometric characteristics. A computer program is also listed which can be used to determine additional results for values of parameters not covered in the design charts. Interpolation of the results presented in the design charts is also possible. Examples of applications illustrating the use of the charts are given, and description of the input/output operation of the computer program is included.
After covering the general uses of plastics in shipbuilding, this guide goes into the specific materials used in constructing vessels of glass-reinforced laminates. Properties of the basic materials are discussed, along with the handling of materials such as wood or foams that will be used with them. Additional chapters cover the storage of the basic materials and the manner in which they are applied in actual construction. This guide also discusses inspection and testing techniques. The references comprise a complete bibliography on the subject, which is followed by a detailed glossary.
As prestressed concrete ship hulls are becoming more widely applied and proposed, especially for service with hazardous cargoes and cryogenics, concern has arisen of the fatigue performance. Tabulation of the probable stress history of a concrete ship in normal full ocean service shows that the cumulative stress ranges lie well below the endurance capacities of prestressed concrete and its components. Fatigue becomes a serious concern only when the cracks in the concrete are repeatedly reopened under a large number of cycles. This is particularly serious for submerged concrete and for concrete exposed to salt spray; i.e., the typical deck and bottom of a vessel.
Hence, cracking must and can be limited by adherence to present design practices and rules.