Mirages

Vergennes
N 44 13.60 W 073 19.68

Well, yesterday was the day after Labor Day. Despite the fact that it was a beautiful day with a nice breeze, we found ourselves all alone out in the main part of the lake. Not a single vessel was visible as far as we could see. Wow, what a difference compared to Labor Day or compared to the weekdays last week. However, before the end of the day we did see five other sails, so the reality wasn't quite so black and white. Still it is remarkable how abrupt the end of the boating season is for most people.

As I looked north up the lake, the mirages were prominent in the morning. I've learned that one can almost always see mirages on Champlain looking north or south. They are cool. The most common mirage is that one sees an island apparently floating in the air above the water. Actually the island is below the horizon and we wouldn't see it at all but for the mirage. The mirage is caused by differences in air density near the water surface that refract the light. Many years ago I read an account of people in Washington D.C. Who saw an image village and palm trees in the sky. The account said that it was traced to a mirage of a village in Africa. I don't think I believe that account; it's too extreme. But the physics are the same.

Clinton County Community College occupies a big cream colored building on the top of a hill near Plattsburg and overlooking Valcour Island. The foundation of the building is about 200 feet above the water. Seen from Shelburne, 20 miles to the south, it appeared to be two buildings, one right side up and the other upside down. The two images joined at the ground line of the building. This too is a mirage. It makes the building appear twice as big and twice as bright than it really is. I'm not trying to show off but just this morning I was reading an article in Scientific American about gravitational lensing. The article said that the distortion of images caused by the lensing make the star images appear brighter than they really are. Aha, that's exactly the same effect as I see with the brightening of the community college.

A third type of mirage is commonly seen on highways on very hot days. It is caused when sunlight heading down toward the asphalt is bent back up by a mirage. It appears to the viewer as if a mirror-like surface was suspended just over the road far ahead of you. It can be very bright. On rare occasions, I have seen the same mirage over water.

Sorry that I can't post pictures of the mirages. I can't take zoom shots from a rolling deck. Here are some images taken from the web of the three types I discussed.
































Anyhow, we took advantage of the nice 10 knot northerly breeze to use the spinnaker. It pulled us at 5 knots all the way down to Otter Creek. It was a fun ride, but somewhat melancholy because it will be our last view of Champlain for quite a while.

Yesterday, arriving in Vergennes we were greeted by some strangers who turned out to be blog fans. One of them, Jim, is a friend of another friend, Craig, back in West Charlton. Craig told Jim about the blog and he has been following it ever since our approach to the Yucatan. Jim wanted to see our new engine. He said that he felt like flying to Florida to help us with the repowering project because he empathized with us so much. This morning, we helped Jim's buddies to climb up their mast to retrieve a jib halyard that got away from Jim. Libby and I contributed the use of our boatswain's chair and lent a hand. The other guys had never done that before and they were surprised at how easy the procedure was.

The AC adapter power brick for this laptop died yesterday. I think it had a cheap chopper method of working and it didn't like the non-sinusoidal waveforms that my AC inverter put out. The brick always ran hot and yesterday it died. I have two others on board, but naturally they use different size connectors at the notebook end. Why in the world can't they standardize on connectors for low voltage DC? I had to cannibalize and splice the wire from another power brick to the connector from the broken one. I hope this one lasts.