Sailors and pleasure boat enthusiasts will all be aware of how difficult it can be to keep an image in view as their vessels roll on even gentle seas. Traditionally mariners have favored relatively low magnification of 7 times combined with a large aperture of 50mm to compensate and to allow a wide field of view for scanning the horizon. The large aperture can also be handy when finding ones way back to the harbor in dim light as the more light captured by the binocular, the brighter the resulting image.
They also tend to favor sturdy traditional porro prism designs which can take a knock and of course survive a splash, of course porro prism designs also assist with the preferred wide field of view. Lately we've seen image stabilization also become favored with those who can afford it.