Naval Architect JB Marine Consultancy Naval Architect  

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Weight Analysis and Flotation

For a ship or boat to float at it's design waterline, a careful analysis of the weight and centre of gravity is required. Matching the calculated centre of gravity of the vessel to the designed centre of buoyancy of the hull is necessary to achieve the designed flotation. Sometimes, weight locations require modification (i.e. position of generators) and sometimes it is necessary to redesign the hull form to move the centre of buoyancy.

Weight calculations are generally thought of as being one of those tasks that no-one wants to do! This is mainly because it is quite laborious and requires some meticulous care in checking all components that comprise the design.

The weight calculation will normally refer to the following conditions:

• Lightship condition, i.e. the bare, dry weight of the vessel

• Maximum Loaded Displacement condition, i.e. including all items of the vessel, ready to leave the harbour for a voyage (including fuel, stores, crew, effects, etc...)

• Variable Load; fuel, water, stores, consumables, etc...

• Other loading conditions, such as half-load, 10% load, maximum KG, etc. which refers to the lightship plus a proportion of the variable load.

JB is able to undertake weight calculations for your project. If you want a full design, then we can undertake the full hull design/optimisation in conjunction with the weight analysis.

If you would like JB to assist you with a weights/flotation issue, or if you would like more information, then please contact us:   

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