Sunday, July 31, 2011
Another remote part of our world is less remote. Credit what you might call MuirCam.
Mount Rainier National Park officials have installed a webcam at Camp Muir, the 10,080-foot base camp used by many climbers of the 14,411-foot peak. They call it Washington's highest webcam.
Images from the webcam are expected to be of wide interest to climbers, who will be able to check weather and cloud levels.
Weather may be the webcam's biggest challenge. No heating system is in place to keep it from icing up. A random check of the view earlier this week showed a gray blur — which accurately describes much of our July. See www.nps.gov/webcams-mora/muir.jpg.
Posted by Voyage Adviser at 7:20:00 PM
Saturday, July 30, 2011
Wednesday, July 27, 2011
Last Update July 28th at 00:01 GMT
After making good time and seeing my first icebergs the wind changed back to the north. I had two days of 15-20kts head winds with super think fog. I never have been a fan of the fog but when you are sailing blindly, surrounded by icebergs with no radar, things get a bit dodgy. Finally when the fog broke I looked around and saw five bergs within a mile of me. Since then the weather has been very nice, but very little wind. Over the trip the temperature has slowly dropped, to the point that in the fog the other day it was in the 30s. Yesterday it was 56 (13c) and today it was 60 degrees (15c)! 60 degrees at 71 1/2 North?! I’m thinking about heading to the beach and going for a swim (just kidding). Yes the skies are blue and the days are warm, but there is no wind and wind is what matters. It’s been slow going the last five days and I have a feeling that this is the way its going to be up here.
Posted by Voyage Adviser at 5:27:00 PM
Tuesday, July 26, 2011
Why use side scan sonar? How does it work?
Side scan sonars are one of the most sought after and effective tools for underwater search. The reason; they can search large areas quickly and "see" what's on the bottom regardless of water clarity. A side scan finds things by sending out a sonar beam which sweeps over the bottom, reflects off any object laying on the bottom, and returns to the towfish. The sonar beam is tramsmitted and recived by transducers mounted on each side of the towfish. The received signal is sent through the tow cable to a topside processor box. After the sonar data is processed, it is sent to the laptop computer for display. The displayed image is a highly detailed two dimensional picture of the ocean, lake, or river bottom, and any objects lying there.
Side scans with low frequency transducers have excellent long range capability, but lower resolution. Side scans with high frequency transducers have high resolution, but shorter range capability. JW Fishers offers three side scan systems; the SSS-100K with a maximum scan range up to 600 meters per side for large search areas, the SSS-600K with a max scan range of 75 meters but high resolution to locate small, soft targets like drowning victims, and the dual frequency SSS-100K/600K which combines the best features of both high and low frequency in one system.
Posted by Voyage Adviser at 4:33:00 PM