Sailors use telescopes of long-focal length to sight distant ships and
landfalls. Most eighteenth-century telescopes of this sort had draw tubes made of wood or carboard. Nineteenth-century instruments were made with brass draw tubes covered with rope, wood or canvas. Most nautical telescopes have a multi-element eyepiece that shows an erect image. And since John Dollond's British patent of 1758, most have been equipped with an achromatic objective lens.
Ref: Deborah Warner, "Telescopes for Land and Sea," Rittenhouse 12 (1998): 33-54.
