NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Logs vs Knotmeters
From: Alexandre Eremenko
Date: 2008 Mar 29, 22:09 -0400
From: Alexandre Eremenko
Date: 2008 Mar 29, 22:09 -0400
More on logs. Norie (1828) describes the use and construction of the "common log" with rope and knots. He says that "in Ships of War and East Indiamen, it is usual to heave the log once every hour, but in Merchant ships only once every two hours." Leckey (1919 edition) has a very nice chapter on logs. He says that timing pieces of wood from bow to stern is called the "Dutchman Log" (See my previous message). He says this is fine for speeds up to 5 knots. Then he describes the "common log" (with knots), "patent log" (with propeller and dial near the propeller) and the "taffrail log" (with propeller on the taffrail) by Walker and Sons. He says that none of these is very good for the speed of 12 knots and more. He favors "outrigger logs", permanently fixed (not towed) but still based on a propeller. He credits this invention to Mr. Frank Pett in Dover and it is clear from the text that the invention was recent. He also mentions "experiments with electrical logs", still propeller-based, as very promising. Alex. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---