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Marine Charts for Google Earth !

Fantastic aerial views of marine charts on to Google Earth!

Check out EartNC limited to North America at the moment:-(


EarthNC for Google Earth is the first ever integration of NOAA ENCs, marine weather and real-time positioning data directly into the Google Earth platform. EarthNC Marine charts feature full-integrated Google Earth renderings of over 600 official NOAA and 70 U.S. Army Corps of Engineering ENC charts.


Sailors now see satellite images of sailing areas with links to :

  • bathymetric data
  • AIS data
  • Weather data
  • Navigation aids
  • Tide data
  • National radar

They even claim that with a laptop running Google Earth and a low-cost GPS receiver, you can use EarthNC as a real-time chart plotter.!!

What a shame they havent got the UK and Europe covered – lets hope the do a deal with the authorities here too.


HTC 7501 Better than a laptop on board ?

HTC 7501HTC have started to ship the HTC Advantage X7501.I think you could easily use this small but very capable device as a substitute for a laptop on board. It has USB ports for interfacing to a NMEA/Seatalk multiplexer and has enough hard disc to store maps and enough power to run charting software….

This is a PDA + GPS + Camera + a multi-region Phone that :-

  • Runs Microsoft Windows Mobile 6
  • 8 Gb hard disc
  • 624 MHz CPU
  • mini SD storage card
  • 3 megapixel camera with auto focus and flash
  • Built-in GPS
  • 5-inch VGA display
  • HSDPA/UMTS (2100 MHz for Europe, 850/1900 MHz for USA)
  • Quadband GSM/GPRS/EDGE for all regions
  • WiFi b/g
  • Bluetooth.
  • Has Direct Push Technology
  • QWERTY keyboard
  • TV Out feature to output contents to an external display such as a Projector or TV when doing presentations or sharing photos
  • You can also print out documents by connecting to a Bluetooth or network printer

…this is the shape of real portability and low power consumption, it can even be a backup GPS …


2.4 GHz 8.5 dBi Omnidirectional Wireless LAN Marine Antenna

If your are looking to increase the signal reception on your laptop while in the marina you may want to check out the antenna from Hyperlink Technologies.

Constructed for all weather operation, the YSC-HG2409UM-RSP features sealed collinear brass elements inside a durable UV-stable machine white fiberglass radome. A sealed end cap and drain holes in the base help prevent moisture build-up inside the antenna.


Protecting electrical contacts

An American friend swears by spraying this stuff from Boeshield on just about everything… he says it is far more robust than WD40 and was developed by Boeing for aircraft use..their is also a testimonial at The Rust Store

From their web site they say:-

Above Deck: Spray on all metal surfaces and wipe off excess.

  • Mast Head Sheaves
  • Stranded Rigging
  • Swage Joints
  • Turn Buckles
  • Snap Shackles
  • Spinnaker Pole Ends
  • Sail Slides
  • Head Foils
  • Stanchion Bases
  • Hatch Hinges
  • Sliding Hatch Covers
  • Canvas Snaps

Below Deck: Spray liberally and Do Not Wipe

  • Instruments
  • Electronics
  • Battery Terminals
  • Running Lights
  • Electrical Connections
  • Engine
  • Steering Linkage
  • Thru Hull Fittings
  • Plumbing Joints
  • Bilge Pump


AIS Class A – What is SOTDMA?

The operation of AIS depends on the Self Organizing Time Division Multiple Access (SOTDMA) data communication technology, which was developed in the 1980’s.

It allows for large numbers of transmitters to share one single narrow band radio channel, by synchronizing their data transmission to an exact timing standard. Under SOTDMA each minute of time is divided into 2250 time slots or 26.67 ms each time slot. With a transmission speed of 9.6 kbps this translates into 256 Bits/time-slot, sufficient for one AIS report.

The exact timing signal of the GPS receiver is essential to synchronize the time slots of communicating AIS ships, as well as providing the position data for each ship. When a ship first “talks” to another ship, it takes up an unoccupied time slot, and it reserves a time slot for its next contact, depending on the status of the vessel according to the standards

For example a ship sailing at 23 knots updates its information every two seconds and therefore “reserves” a time slot 75 slots on from the first contact (2250/30=75) and so on).

The range of the system is the VHF horizon for each AIS-ship, with the ship in the centre of its own communication “cell”. The size of this cell will adjust to the traffic density, if slot capacity starts to run out, the system will automatically discard targets at a greater distance and assign those time slots to targets of greater importance.