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Prismatic Coefficient

What Hull Shape Is Best?

Back at the dawn of maritime history, a coastal dweller first took a log and ventured out on the water. Over time his craft evolved from a rough log to one that had shape at the ends and was hollowed out. These changes to the basic log shape were the first example of modifying a hull form to increase carrying capacity, improve ride comfort, and to reduce resistance. Since then, shipbuilders, naval architects, and ship owners have experimented with hull shapes and the number of hulls to find the "best" design. Let's look at some of those variations to understand the challenges of choosing a hull shape. Monohull Design The basic monohull can be defined by six key numbers: length, beam, depth of hull at midships, design draft, prismatic coefficient, and displacement. Length, beam, and draft are familiar to everyone. Depth of hull at midships gives an idea of the freeboard as well as an indication of the hull strength in bending. The prismatic coefficient is a measure of how much shape there is in the ends of a hull. A high prismatic coefficient means that the ends are full such as a tanker bow. A low prismatic means that the ends are fine, with little volume, such as a tugboat stern. The choice of what dimensions to use depends on the intended use of the vessel. For a passenger vessel, there are considerations of carrying capacity, operating environment, and type of operation


BMT’s Fleet Management System to Debut at Nor-Shipping

Photo: BMT SMART

BMT SMART Ltd., the specialist fleet and vessel performance management company of BMT Group, will launch its new SMARTFLEET Management system at Nor-Shipping in Oslo next month. Technical experts will be on hand to showcase the system and its capabilities whilst discussing with delegates their specific challenges and needs.    Peter Mantel, Managing Director of BMT SMART commented, “Whilst there are cost savings to be made through on-board optimization


Safety: Slip and Fall Accidents in the Marine Environment

Because the exposure to the marine environment and motions of a vessel, slips and falls are a significant source of personal injuries in floating equipment, probably substantially greater than most industry groups. Although there are a good number of publications, books and articles written regarding the subject of slip and falls, there are almost none addressing the conditions found in a marine environment, which influence slips and falls. Consensus


RoPax Propulsion Concept Proves Efficient

Wärtsilä, in conjunction with the Finnish research project SEATECH 2000+, has been developing some new machinery solutions for RoPax vessels. A promising concept is a semi-diesel electric machinery, where mechanical propulsion is combined with a diesel electric power plant. This new RoPax concept was presented for the first time at the Europort 2001 exhibition. The RoPax vessel has a semi-diesel electric machinery featuring a diesel mechanical part driving a conventional CP propeller and a


MHI LNG-FPSO Approval for Two Tank Types

Mitsubishi Heavy Industries, Ltd. (MHI) completed development related to floating production, storage and offloading units for liquefied natural gas (LNG-FPSO), and has obtained two kinds of approval in principle (AIP) from major international ship classification societies. In tandem with intensified activity in medium- and small-scale offshore gas field development, demand for LNG-FPSOs, a new method of gas production offering movable capability, has been increasing globally


NASSCO Licenses LNG Containment Tech to Braemar

Image: Braemar

General Dynamics NASSCO and Braemar LNG BV announce LNG containment technology licensing agreement   General Dynamics NASSCO and Braemar LNG BV, a wholly owned subsidiary of Braemar Shipping Services PLC, have signed a technology licensing agreement for Braemar to use NASSCO’s intellectual property in its design and construction of Flat-Panel, Semi-Membrane, Prismatic-Shaped (FSP) LNG containment systems.   


DSME's New LNG Tank Technology Approved by LR

ACTIB ((Aluminium Cargo Tank Independent Type B) tanks - prismatic, large, independent cargo tanks -  reduce sloshing, suitable for LNG containment The ACTIB tanks, constructed of insulated aluminium 5083, will have the world’s largest storage capacity in an independent, insulated LNG tank system. The volume capacity in the initial design will be nearly three times larger than comparable types currently in operation.


FSP LNG Containment System Construction To Begin Soon

Chairman Zhang Mi

  The joint venture group FSP LNG BV stated that it is taking the FSP LNG Flat Panel Semi-membrane Prismatic Type B containment system through General Design Approval (GDA) with the American Bureau of Shipping in Houston, and is projecting that construction of the first tank will begin at the end of this year.   Formed earlier this year to take the FSP LNG containment system through the general approval process, the group comprises Braemar Engineering


FinMin Says to Stick to Oil Duty Cuts Plans in 2017

Russia's Finance Ministry will go ahead with plans to lower oil export duties next year if prices do not increase significantly, Deputy Finance Minister Ilya Trunin told reporters on Monday.   Russia had scrapped plans to cut the duty for this year due to lower prices of oil, the country's main exporting commodity. Oil producers had expressed concern that the government would increase the tax burden as it tries to make up the shortfall in state coffers.  


Is There Often A Rose Between Shipping’s Thorns?

Graph: Clarksons Research

 Historically, a prime characteristic of the shipping industry has been that when one sector is performing weakly there is generally another that is strong, and that even when most of the markets are down there is often one which provides at least some counterbalance by performing more robustly.    Clarksons Research says that today’s market climate suggest that it’s worth taking a look at this interesting element of the industry’s make-up.  


McClain Appointed MD of Braemar Engineering

Sheila McClain

Braemar Shipping Services Group PLC is pleased to announce that Sheila McClain, Executive Vice President of Braemar Engineering, has been appointed Braemar Engineering's new Managing Director.  Sheila will continue to be based in Houston


DNV GL Okays New Floating Power Generation Concept

A 3D model of the FLPS concept. Note: “FLPS” is the registered trademark of IHI Corporation in Japan. Image: DNV GL

 DNV GL has given IHI Corporation Approval in Principle (AiP) for its FLPS (Floating LNG Power Station) concept.   The formal handover of the Approval in Principle took place in Tokyo on July 5. The design has been found to comply with DNV GL class standards and other relevant industry


Electric Motors for Marine Applications

A waterproof motor with stainless steel exterior (Photo: Empire Magnetics)

Empire Magnetics President Richard Halstead discusses the critical considerations necessary for engines operating in Arctic waters.    A large number of vessels sail in more than one ocean, from warmer seas to arctic waters, so motors for marine applications must be versatile enough to


Overcoming the Propeller Supply Bottleneck

Image: Hydrocomp

Hydrocomp’s ProCad facilitates in-house Process Control of Propeller Design and Manufacture.   Maritime Tactical Systems Inc. (MARTAC) is a Florida-based company building next-generation unmanned vessels for military applications


Great Ships of 2014: Gas Star - 84,000 CBM LPG Carrier

HHI_Gas Star_PHOTO WEB.jpg

Gas Star is the first of two 84,000 CBM LPG Carrier built by Hyundai Heavy Industries for KSS. The vessel measures 225 x 36.6 m, with a depth of 22.2 m and a design draft of 11.6 m.  The ship is powered by a HYUNDAI-MAN B&W 6S60MC-C8.2 main engine with a NCR output of 11,340 kW at 89


Braemar Sub-Licenses FSP Containment System

Braemar LNG BV, the wholly owned subsidiary of Braemar Shipping Services PLC, has issued a sub-license to FSP LNG BV for the design and construction of a new Flat-panel, Semi-membrane, Prismatic-shaped (FSP) containment system, under the terms of the license it holds with General Dynamics NASSCO


Gazprom Building up Resource Base

Geological exploration in Krasnoyarsk Territory

In 2014 Gazprom Group (excluding Gazprom Neft) performed exploratory drilling of above 125,000 m of rocks, constructed 32 prospecting and exploratory (7 and 25 accordingly) wells. Over six thousand linear kilometers of 2D seismic profiles were processed


BOURBON Installs Submarine Cable for Sabella D10 Project

NSTALLATION OF THE CABLE IN PICTURES

BOURBON is participating in a tidal turbine connection project off the island of Ushant (Brittany, France), a first in France. A pioneer in the towing and installation of the first floating wind turbine off the coast of Portugal, BOURBON is committed in the field of renewable energies and is now


MHI Debuts Non-ozone-depleting Refrigerant

Logo

  Mitsubishi Heavy Industries, Ltd. (MHI) has developed a new series of centrifugal chillers, dubbed the "ETI-Z Series," adopting a new refrigerant, HFO-1233zd(E), that offers outstanding environmental compatibility. The various models in the new series will be progressively


Bal Seal Adds Low-friction Seals Test Service

Photo: Bal Seal

Test service enhances Bal Seal offering for low-friction seals, verifies friction and leak rate for seals up to 22 in. diameter   A new test service introduced by Bal Seal Engineering, Inc. offers verified performance results for Bal Seal low-friction spring-energized seals used in


Altair's LNG Containment Concept Earns AIP from ABS

Classification society ABS has granted Approval in Principle (AIP) to Troy, Mich., based Altair for the Cubic Donut Tank System (CDTS) LNG containment concept. The CDTS concept is adapted from a patent first filed nearly 40 years ago. The principle behind the initial design concept is the


Foreship: New CFD Methodology

flyer_bowshot WEB.jpg

In the quest to model real conditions faced by ships at sea for design purposes, earlier this summer Foreship unveiled details of a live project that has factored real sea states into CFD-based hull form optimization. The company reports that the results of ‘in wave’ analysis had


Hard Problems Demand Soft(ware) Solutions

ABB

Make no mistake, the commercial maritime industry will always revolve around heavy duty machinery and mega-machines designed to weather some of the toughest operating conditions on earth. But in recent years a proliferation of Software Solutions has evolved to help the machines operate more


Conflicting Objectives in Ship Design

Figure 1: Detailed geometry for STAR-CCM+ simulation of ship self-propulsion

Enviro, Safety Regulations Conspire to Complicate  the Marine Classification Business “ABS is first and foremost a safety company,” says Richard Korpus, “but safety can arise on many different fronts. It can refer to the safety of a high-valued asset


Sea Hawk Debuts VMG Hard & Fast Racing Finish

Fresh Water Boaters Hard, Fast Racing Finish Sea Hawk

Sea Hawk today  announced the introduction of VMG Hard & Fast Racing Finish, a revolutionary new bottom coating geared specifically for fresh water sail boaters and power boaters looking to enhance the performance of their vessels. VMG






 
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