unnavigatable

From un- +‎ navigatable.

unnavigatable (comparative more unnavigatable, superlative most unnavigatable)

1. Alternative form of unnavigable
   • 1880 May 18, “James River Navigation”, in The Jamestown Alert‎, volume 2, number 43, Jamestown, Dakota Territory:

     A week ago to-day, the launching and christening the first and only steamer on the James river, said to be the longest unnavigatable stream known, took place at Jamestown.

   • 1897 October 5, “Heat, Drought and Fires. Chicago’s Hottest October Day in 27 Years. Smoke from Forest Fires Makes Navigation on Lake Michigan Perilous. […]”, in Fall River Evening News, volume XXXVIII, Fall River, Mass., page 5:

     Lake Michigan has been almost unnavigatable on account of the smoke and fog.

   • 1905 July 6, “Rushing Supplies. Bridge Contractors Making Haste in Time. Rover Getting Very Low and Indications Are That Steamboats Will Have to Suspend for Summer.”, in The Chattanooga Daily Times, volume XXXVI, number 204, Chattanooga, Tenn., page 5:

     Owing to the fact that the river will be so low as to be unnavigatable within the next few weeks, the contractors on the new bridge are having a large amount of supplies and building material brought down the river.

   • 1905 September 21, The Weekly Wymorean‎, volume 23, number 11, Wymore, Neb.:

     At certain seasons of the year the streams of that region are unnavigatable because of the clouds of the insects which fill the air and make life unbearable.

   • 1906 January 10, “He Had Laid Down to Die. But Generous Captain Hoyt Found and Saved Him. At Sea in Disabled Launch. […]”, in Elmira Gazette and Free Press‎, volume 62, number 8, Elmira, N.Y.:

     The launch was found tossing in the heavy seas, coated with ice both inside and out, off the Isles of Shoals, fifteen miles from port, to which point it had drifted after the engine had broken down, leaving the craft unnavigatable.

   • 2005, Torin Monahan, “Flexible Governance”, in Globalization, Technological Change, and Public Education, Routledge, page 140:

     Checking the Board’s Web page on LAUSD.NET reveals a poorly designed, almost unnavigatable textual collage of links to “Understanding Board Meetings,” “Board Rules,” and “Board Agendas,” but finding out where and when is completely oblique.