| X = maximum length of gangway when extended Y = minimum length of gangway when retracted K = The minimum distance to maintain between the centre of rotation of the gangway and the centre of rotation of the ram (K) a and ' = The total angle the gangway can achieve. G = width of fixing bracket The drawing have been studied considering a vertical transom.Variations of the transom angle and the different heights of dimension K will produce different values of angle a and |