Summer 1930 - Britannia racing Shamrock V, the first of the J Class cutters. The towering sail plan of 1926, proving not too successful, its height was reduced and in place of the top sail with its top sail yard, the yardless jackyarder was substituted. The picture shows another stage of Britannia’s march towards the modern Bermudan plan, her socketed top mast and top sail yard has given place to the so-called Marconi rig.