FLOATING BOX BY E. FRANKENBERG, HANNOVER, GERMANY, 1896: SIDE VIEW, SECTION

Joachim Schult trans Inge Moore, Curious Boating Inventions,Taplinger Publishing Co, 1974

He also had a variation on the theme patented [right], in which 'with the aim of increasing the volume of air surrounding the body the watertight cloth enclosure is enlarged into a box shape above the knee and sealed with a harmonica-type lid (with access hatch), so that, if necessary, several persons can be accommodated.' There was only leg-room for one, though!