Page 70: of Marine News Magazine (November 2015)

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WORKBOAT DESIGN

P considerably,” adds Dykes. “You have clips versus dogs,

ERFORMANCE

Any discussion concerning performance requirements of coaming(s) versus frame, free opening versus clear open- marine closures will inevitably focus on design pressures. ing, rough opening versus plate cut, for instance. Work-

Closures generally must correspond to one of three tight- ing with builders in different countries around the world ness standards. Water-tight closures must withstand water requires a bit of ? exibility, based on the varied descriptions pressure from either side of the opening, while weather- in closure requests received.” tight closures are intended to withstand pressure from one side only. Spray-tight closures, typically mounted higher on F

EATURES a vessel, are built to withstand penetration from spray and Beyond performance criteria, the second consideration rain, but not standing water. “I ? nd that tightness varia- in closure selection – and a key factor in determining end tions are often misunderstood,” says Mund. “It is environ- cost – is the feature set a given window, door or hatch may mental considerations that impact design pressures. Perfor- be required to include. It is tempting to consider features mance standards are thereby dictated by where the closure as the elements we can physically see. Doors and hatches is located on a vessel, and its exposure to the environment. may or may not include inset windows, for example, and

They will also be determined by additional factors, such windows may or may not be required to open. Should any as meeting relevant ? re-rating requirements, for example.” desired glazing be clear, or frosted for security consider-

One of the challenges facing closure manufacturers is ations? Is Low-E glass required? that of satisfying regulatory requirements when variances Although primarily used in recreational yachts, Smart exist in international standards. “Apart from differences Glass – which can be adjusted from clear to opaque at the in design/build standards, the nomenclature used in dif- push of a button or even remotely, from a cellular tele- ferent countries when describing required features varies phone or iPad – is beginning to ? nd acceptance in some

November 2015

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