do i only need my radar at night

do i only need my radar at night
While we were at our local yacht club for a weekend of fun and camaraderie,
instead of heading home Sunday afternoon, we decided to stay through Sunday
night and take the boat back to the marina early Monday morning. This seemed like
a great plan as we could get out another bottle of Port and have an evening cigar
with the other boats that also planned to stay another night. The Monday morning
tides looked good and coincided with sunrise almost perfectly. Our plan was set, we
would get under way at 0630, have breakfast and get dressed for work in route,
and as soon as we are back in the slip with the boat secure we would be off to start
the new week. The 45 minute ride down the Calaveras River and San Joaquin deep
water channel is usually serene with not many boaters on a cool Monday morning.
Everything was going as planned when we exited the Calaveras River and made the
turn into the Stockton Deep water channel. It’s chilly outside but we are toasty
warm in the pilothouse with a hot breakfast cooking, a fresh cup of hot coffee in
hand and the first mate is getting ready to take hot shower. Approximately ¼ mile
ahead I spotted the dreaded toule fog, hanging low on the water and looking pretty
thick. As we entered the fog bank our visibility went to near zero so we immediately
went into limited visibility mode; putting breakfast on hold, transferring control to
the weather helm, slowing our speed, activating the fog horn, making sure the
navigation lights are on, and checking our position. At this point some skippers
would be trying to remember how to turn the RADAR on. In our case, the boat
never leaves the dock without the RADAR operating. Good weather or bad our
RADAR is always on so it was simply a matter of adjusting the range and we are
ready. My flybridge is open to the elements but offers an excellent 360 degree view
and allows me to hear very well. While not as warm as the pilothouse, with a jacket
on and a hot coffee in hand, standing at the flybridge helm on a chilly fall morning
it is just another kind of boating fun.
Fully surrounded by thick fog we start navigating down the Stockton Deep Water
Channel when my second fog whistle is answered with another. Only this one is the
deep low tone associated with large commercial ships. A quick adjustment on the
RADAR range, and yes, there it is, just a few miles upriver is the unmistakable
return of a large ship. I take a quick plot of his position and activate the ARPA
(Automatic RADAR Plotting Aid) in an effort to determine his course and speed.
The ARPA function takes three minutes to obtain an initial fix with course and speed
and six minutes to plot an accurate vector. While the ARPA computer was doing its
calculations I was also doing them manually. My initial plots showed the ship to be
going in the same direction as us but at a greater speed. It was a long three
minutes waiting for that initial ARPA information, but when it displayed it confirmed
my estimation, that ship was down bound at nearly twice our 4 kts speed and may
overtake us before we reach the turn to Fourteen Mile Slough! In three more
minutes I will have much more accurate information. Making good use of the next
three minutes waiting for the computer, I hail the pilot on the ship to confirm that
he knows we are ahead of him. In our brief radio exchange we have confirmed that
his RADAR operator knows that we are in the river, has us plotted, and we have
agreement that we would stay in the channel, close to the starboard side, and that
he would overtake us on our port side. This is turning out to be an exciting morning.
While using our RADAR to navigate in the channel and to track the position of the
bulk carrier that was closing the distance between us, for nearly the next hour we
navigated the Deep Water channel with fog whistles answering each, that large
target getting closer every minute, and continuously calculating if we would be
overtaken before turning into Fourteen Mile Slough. The bulk carrier never did
overtake us, but with less than 150 foot visibility we never did see him even though
our RADAR showed him to be less than ¼ mile behind us when we made the turn.
Commercial captains operating vessels in San Francisco are required to hold a
USCG RADAR certification and re-certify regularly. Not because I have been through
the certification classes, but because we always use our RADAR, our skills are
current. By being able to competently operate our electronic aids to navigation
there is far less stress when conditions like this occur. Having kept our speed slow
and only passing a few fishermen out for that early bass, we arrived safely at our
dock just a little later than desired.
Most marine RADAR manufacturers provide good documentation on the basic
operation of their set. Each device operates a little differently but the basics are the
same. Some high end units have controls for sea state, rain, clutter, short pulse
length and interference, to name a few. All modern RADAR sets have an AUTO
mode that uses preset settings for these controls except the gain and range. If
properly installed and calibrated the AUTO setting will get you better than 90% of
the performance. This is a good place to start as you familiarize yourself with your
particular set. Properly adjusted, even small boats paint a good return on most
modern RADAR units.
RAdio Detection And Ranging, RADAR. The first concept was demonstrated in the
late 1880’s, a primitive system developed by Tesla in 1917, and the first functioning
system was operational in 1934. The same basic principle is used in today’s modern
sets; an electromagnetic signal is transmitted, it reflects off of distant objects and
is received by the set, range and bearing is calculated and then displayed. The
powerful signal processing capabilities we have on today’s units enable our
recreational RADAR’s to have easy to understand displays and easy to use controls.
Here is a shot of the RADAR display one late summer afternoon in San Francisco
Bay when the fog rolled in. On a RADAR display we are usually in the center and
indicated here by the +. The range is 1.5 miles and each ring is 0.5 miles as shown
in the upper left corner of the display. I am roughly half way between the Golden
Gate Bridge and Alcatraz with the Golden Gate shown at the bottom of the display
and Alcatraz in the upper right quadrant. Angel Island is in the upper left. One half
mile ahead and just off to the left is Harding Rock RACON. Many of the prominent
landmarks in San Francisco have an active RADAR transmitter that sends out a
beacon that is picked up by our RADAR set. The transmitted signal contains a Morse
code letter for identification and in this case it is the letter “K” as shown by the
long-short-long pattern. These RACON’s help us to determine an accurate position.
If you look closely you can see more than 20 targets within 1.5 miles of my position,
all moving in different directions, and at different speeds. This is a pretty typical
display with good target definition that allows safe navigation in restricted visibility.
If this display looks confusing, you need to spend some quality time with your
What lessons did we learn on that early morning cruise? First, RADAR is one of the
best tools you have on your boat if you are competent in using it. The best time to
practice navigating by RADAR is when you don’t need it. Have the unit powered on
and scanning on those bright sunny days so that you can get used to how the set
operates and what the different targets look like. Whether I’m running a passenger
ferry in SF Bay, on a coastal delivery 20 miles offshore, or tooling around the delta,
I practice using RADAR all the time. If there is any possibility that I will be
underway between dusk and dawn, or if fog is forecasted, I will not leave the dock
without an operating RADAR. This is one of the best safety tools you have on board
when used properly.
Second, for safety the use of a fog horn is essential.
Third, making radio contact with another vessel in or near an area of restricted
visibility makes for safe maneuvering. In this instance communicating with the pilot
on the commercial vessel made for a safer transit for both of us.
You made a wise investment when you purchased your RADAR, study the manual,
get comfortable with the adjustments and use or your RADAR, take a class if you
want to become proficient. When limited visibility conditions occur, you will be more
competent in the safe operation of the vessel and may even learn to like operating
at night. RADAR, like any other electronic device, is another tool we use to make
our passage safe. For most, boating is recreation; our time on the water should be
as stress free as possible.
Have a good story to tell. I love a good story. Email me at
Pat Carson is USCG licensed captain and operates commercial
passenger vessels in the San Francisco Bay and Delta area. He is a
partner with Bay Area Yachting Solutions, a company that provides
instruction, local and coastal deliveries, and maintenance of
recreational vessels. To contact, email
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF