navigable

adj

1. Capable of being navigated; deep enough and wide enough to afford passage to vessels.

   “[...] on July 16, 1790, a public meeting [...] unanimously approved of a scheme for making the River Soar navigable from Leicester to Loughborough, and "a cut or rail-way from Swannington and the neighbourhood to the bason at Loughborough."”

2. Seaworthy; in a navigable state; steerable.
3. Steerable, dirigible.
4. Easy to navigate.

   “This Web site isn't very navigable. I can't tell which image links to which page.”