There it is. "The number of Knots that slipped through a sailor's hand in 28 seconds denoted the speed of the vessel in Knots."
And
"A Knot is placed every 47ft - 3 in."
This knotty info was in the bookstore at the San Francisco Maritime National Historical Site, right near Fisherman's Wharf. We got to board an old ferry and this tugboat - Hercules.
They also have a workshop where craftsman restore old boats and ships. I was intrigued by the 3rd label on this set of drawers of tools.
What was in the Childhood Dreams drawer? It turned out to be wrenches, but I guess it represents why a lot of the volunteers spend time there working on the boats.
Here's the view from the roof of the building at the AirBnB we're staying at. It's a great, large bedroom and bathroom in a fifth floor apartment. The owner is at the other end, and while we're allowed to use the kitchen and living room, we don't have much time. And it's only six blocks from the family. And it was a great price.
But...but...but why 47.25 feet you ask, why 28 seconds? Well: because the relationship between those two numbers is exactly the same as the relation between 6030 feet (aka one nautical mile) and 3600 seconds, or one hour. so one "knot", instead of being a measurement of distance becomes a measure of velocity = one nautical mile per hour.
ReplyDeleteBut what's special about 6030' you ask. Well, it is 1/5400th of the distance between the equator and the geographical pole, or one minute of latitude, the basic unit of navigation and of astronomical observation.
Pedanticaly yours,
Bill Butler
Ashland, Oregon
Wow Bill, you should be working at the SF Maritime Historical National Park. I thought it was fascinating, but was wondering how those particular numbers came up. Thanks for filling in the rest of the story. And, as always, it's good to hear from you.
ReplyDeleteOkay. Today's topic: what is a meter? (39 inches is not the answer.)
DeleteWithout looking it up,I thought it was something like the distance from the king's fingertips on his outstretched hand to his nose. No, I guess that was a yard. So tell me.
DeleteWell, I kinda fluffed the question, because a meter is obviously one thousandth of a kilometer. The point I wanted to make is the geographical root of metric system: A kilometer is 1/10,000th of the distance from equator to geographic pole.
DeleteVery interesting and informative column, even for a landlocked, land lubber like this retired farmer.
ReplyDelete