Sunday, February 8, 2015

Radar Love


English Bay with the fog rolling in - photo by Junie Quiroga
Contrary to popular belief it doesn't rain all winter long in Vancouver but, on those clear sunny days a different form of condensation can occur and, that is something called fog. Sunny days mean starry nights and starry nights are much cooler than cloudy ones so when the sun goes down and the land and ocean starts to cool off the rising warm air meets the cool air above and forms fog. Normally this only lasts for the night but, being hemmed in with mountains, the cold air can remain stationary for days acting as a lid over the waterways and keeping the fog in place until the next round of rain appears to clear the air.

View of Vancouver fog from the local mountains
While the view from the local mountains can be spectacular, it makes visibility difficult for city dwellers and non-existent for anyone on the ocean.  There really isn't anything more terrifying than unexpectedly encountering fog and having to cruise blindfolded, particularly if a freighter suddenly appears in front of you. If you were trying to fly an airplane through fog or cloud you would need to have a license with an instrument rating but for boaters there aren't any legal requirements.

Typical GPS device for recreational boaters
It was only recently the government brought in licensing requirements to operate a recreational boat but there are no rules around required instrumentation or how to use any of these devices. Until not so long ago most recreational boaters got along with just a compass and paper charts but, more recently, there have been a large number of marine GPS chartplotter navigation devices for boaters to choose from that integrate ocean charts and satellite tracking (something every new car owner is now getting to experience along with anyone in possession of a smartphone). While a GPS is great for knowing where you are and helping you plot a course to where you want to go, it doesn't help you see anything if you are in fog, and for that you need radar.


Radar is the acronym for "radio detection and ranging" and, while the various components of a marine radar system are quite complicated in their design, the concept and process is actually as simple as understanding how a flashlight operates. Walking in the dark and using a flashlight you're actually sending out light waves that reflect off any object in front of you and bounce back to your eyes with your brain telling you what you're seeing and how far away it is. In the case of radar, radio waves are used instead of light waves to do the same thing.



A piece of equipment called a magnetron produces the radio waves, and an antenna, working as both a transmitter and a receiver, sends them into the air in front and then listens to the reflection to see if anything was picked up. Anything picked up is then processed by another piece of equipment and displayed on a screen that lets the operator know where any nearby ships are and how fast they are travelling. It all happens very quickly with radio waves travelling outward and bouncing back at the speed of light which is 186,000 miles per second or 7 times around the world in one second.

Ship radar display

While the safest way to navigate is in clear daylight, a mariner in the Pacific Northwest can easily get caught out and having radar can be a life saver.  It's mandatory of course for commercial vessels but more and more recreational boaters are having it installed as well.  When you're trying to get home to loved ones it isn't the message you send them that's important but rather the message your radar sends to you.

Freighter appearing out of the fog - photo by Junie Quiroga

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