A pocket monocular may be the answer.
For a given magnification, monoculars are lighter and
easier to hold steady, and simpler to use because there is only one set
Many sailors also appreciate the fact that they
can use their other (now spare) hand to hold on to the ship!
• 10x magnification through a 25mm object
• Tough rubberised casing and supplied with
a leatherette belt pouch. 4.5" long.