Maritime Hull and Machinery Book report Essay

Introduction This book about the elements of shipping Emphasis is also placed on professionalism and the need to have the latest technology and professionally qualified personnel to operate a shipping service today. It remains essential reading for the shipping executive along with students and academics with an interest in the shipping industry. Hull and Machinery includes studies about cutting by a wedge of longitudinally stiffened plates for application to the grounding resistance of single hull and double hull ships. Two types of ship hull design were used as prototypes for the development of small scale models. A conventional longitudinally stiffened Single Hull (SH) and the Undirectionally Stiffened Double Hull (USDH) design. To model the cutting experiments the complex deformation patterns observed in the damaged specimens were simplified to obtain a closed-form upper bound for the steady state cutting force required for the USDH specimen. An existing closed-form upper bound solution for the wedge cutting initiation force of a single plate was applied to the longitudinally stiffened single hull specimens by smearing the geometry to obtain an equivalent thickness single plate. A total of eleven cutting experiments were conducted using six different wedge geometries. Early work in grounding prediction has been to perform plate cutting experiments which produced empirical formulas for the work to cut a flat plate. The main purpose of Hull and Machinery is to provide the ship owner with an expectation of status quo regarding a vessel’s operational ability during a maritime enterprise. Since marine perils are a risk that the ship owner assumes each venture. Improper design and the improper selection and use of materials is the primary cause of most non-damage related structural failures. Contrary to common belief, actual manufacturing defects only rarely figure into structural failures. It should come as no surprise to any surveyor that the ship building industry, much like the automotive industry which, after more than 70 years of mass production, backed up with their enormous financial resources, is still fraught with frequent design defects. Body Efforts have been quite significant in quantifying the force required to cut a single plate, but do not account for the effects of stiffeners and inner hull that exist in the actual geometry of ships. In order to adequately predict the lift and drag forces in a ship undergoing a grounding accident and the subsequent extent of damage. Global lifting of the ship against gravitational forces is done. There are Friction forces between the bottom hull plating and the grounding surface, plastic deformation of the hull girder, and forces required to fracture the hull structure. In grounding, the ship initially lifts and rides over the rock causing only hull indentation. Once the force due to the weight of the ship overcomes the plating membrane strength,   the hull plating ruptures. Kinetic energy of the ship is given up to friction forces, plastic deformation, and fracture as tearing over a length of the hull plating ensues. The work in this book report it does not account for the lifting and subsequent rupture of the ship, but assumes that the tearing of the hull plating is well progressed. The indentation and rupture of a ship hull is the structural design of a ship typically starts by determining the loading conditions that the ship will be experiencing during its service life. Normal operation includes loading conditions such as bending of the hull girder (hogging, sagging, and still water), cargo live loads, structural dead loads, liquid loads, cyclic fatigue, and exterior hydrostatic loads. The ship is also subjected to infrequent loads such as flooding and dry docking, and in the case of naval vessels, combat loads such as underwater explosions. The structure is designed, analyzed, and optimized to withstand the normal loads to some allowable stress level, and to remain intact under extreme loads subjected to a vertical load is considered a separate mechanism. Mission characteristics such as payload capacity and endurance determine the size of the ship. This establishes the length, beam, and depth of the ship, and, hence, the structural dimensions. Modern ships make use of this principle of construction. The said construction is the sum of its many parts while a fiberglass boat hull is essentially one component. The combination of molded hull and deck joined together creates a unified whole that is much stronger than the sum of its parts. But ships are proportionately far heavier and are subjected to different stresses. While the bottoms of hulls take the major brunt of stresses, and must be designed to withstand them, the construction still plays a major role in providing strength to the overall structure. In actual operation under heavy conditions, the hull sides of most boats will deflect to greater or lesser degrees depending on how well it is designed. This is the result of impact loading, bending and torsional loading on the hull caused by high velocity over waves, porpoising and so on. If you’ve ever wondered why there are ships have rub rails falling off and weak and damaged hull/deck joints, you probably thought that this was primarily due to hitting up against dock pilings. But the real reason is that there are ships who have poorly designed hull/deck joints that are simply lap joints screwed together. It is the stress transferred from the hull bottom to the hull sides and thence to hull/deck join that causes the screws that join these parts together to break loose. Putting screws into fiberglass is a terrible means of making connections. Screw joins are simply too weak to work effectively. Partial bulkheads are really nothing more than frames and do not serve any greater function than frames. It is a mistake to call a hull partition with two doors in it a bulkhead, for it is really only a partition or a partial bulkhead at best. Surveyors often mistake partitions for bulkheads. Remember that to be classified as such, a bulkhead must be serving the purpose of tying the four sides of the hull together (bottom, deck and sides). If the shot full of holes and openings, it’s not achieving that purpose. Conclusion It is important to be aware of the nuances and exclusions from Hull and Machinery cover as well as to be aware of cover options and requirements. For instance, although the ship, equipment and spare parts are covered by the Hull and Machinery insurance, loose items that accompany the ship in its trade, but which cannot be deemed to be a part of it, e.g. stores and supplies are covered under the ITCH, but not under the Plan. As a result, the ship owner may consider purchasing additional insurance cover for items falling outside of the Plan’s cover provisions. However, many times, the loss and/or damage of such items fall well below the deductive. Another important consideration is cover of items that are not normally on board the ship for an indefinite or prolonged period of time. The Plan’s prerequisite for covering equipment and spare parts under the Hull and Machinery cover is that they are normally on board. Therefore, an individual assessment should be made. Even less did I anticipate the effect on how the hull would handle with a 41% overall weight reduction. Scale model testing revealed the boat to be so light that it would pitch and roll so violently that it would be uninhabitable to human beings. It developed a whip-snap roll in a 3†² sea that would literally throw people off the deck. Or when pitching, launch them like a trampoline. However, there has been some extension into production building mainly so-called niche markets such as race boats, both power and sail. And to the extent that it is clear that the production boat building industry does not possess the necessary capital resources, nor the profit margins to sustain them, their incorporation of this technology into production building is very likely to continue along the lines of trial and error. What this portends for the surveyor are the risks of failing to locate design failures during surveys, failures involving design, materials and construction techniques that fall into the realm of the experimental. Make no mistake about it experimentation with new materials directly into a product is the norm, not the exception. With this basis understanding of the principles of good hull design, we can now begin to study the effects of what happens when these principles are violated. References Branch, Alan E. Elements of Shipping 7th Ed. Routledge Publication. N.Y. ISBN 0748760393 US Cost Guard Guide to Regulations for Passenger Vessels. (2001). http://www.uscg.mi/ng/9-m/nvic/301/n3-01.pdf Kahloism. (1971). Ship Construction. http://www.freepatentsonline.com/3625174.html Shipping Container. (1974). http://www.freepatentsonline.com/3782619.html