The Surface Effect Catamaran – Progress in Concept Assessment

Abstract

The surface effect catamaran incorporates twin high length‐to‐beam cushions to support a low length‐to‐beam platform. The performance characteristics of the resulting vehicle, i.e., the resistance and head sea motions, are equivalent to a higher length‐to‐beam surface effect ship. The high lateral stability which results from the widely spaced hulls and cushions of the surface effect catamaran provides several advantages not inherent in conventional surface effect ship configurations. These advantages are manifested by high cross‐structure height and reduced structural loads without reduction in static or dynamic roll stability. For an 800‐ton ship the widely spaced cushions provide a capability of controlling off‐head sea types of motions and the virtual elimination of green water over the deck up through Sea State 6. Model tests have validated cushionborne and hullborne resistance computer prediction programs. Head sea motions tests have justified the use of high cross‐structure height to minimize high slam types of structural loads. Preliminary design and model tests indicate the potential for the surface effect catamaran to operate as an open ocean ship in smaller sizes than heretofore thought possible. In addition, its planform and large volume provides pay‐load capabilities of much larger ships.

The Security Apparatus and the British Left, 1950s–2000s (Part II)

“…Special Branch gathered intelligence on the planning of the demonstrations, 58 revealing that protestors believed that "the continuation of sporting ties between British [sic] and South Africa bolsters the morale of the apartheid regimes and their supporters" 59 and wanted to "focus attention on South Africa's anti-apartheid policy by denying white South Africa any sporting outlets beyond their own country." 60 To avoid burdening police with serious public order maintenance duties, endangering diplomatic relationships with other African countries and disrupting trade relations with South Africa as a consequence of the likely public disorder that the tour would have caused, Home Secretary James Callaghan requested of the Cricket Council that the South African team tour be canceled. 61 But the planned demonstrations against the rugby tour went ahead.…”