A while ago on the cpakayaker listserve there was discussion that boaters, even casual ones, had the responsibility for knowing, understanding, and keeping current on the nautical rules of the road, exclusion areas, etc.  It was pointed out that the changes are published in the Notice to Mariners which is updated just about weekly on the web. 

Also, a while ago, I posted about NOAA now providing free booklet charts for the entire Chesapeake Bay area.  These are free, downloadable to your PC, and can be printed on standard 8.5 x 11 paper.

 

Now, NOAA has incorporated the Notice to Mariners into the BookletCharts, which will be updated weekly to include all the notices in effect. 

The NOAA bookletcharts are available via www.NauticalCharts.gov/bookletcharts

 

Print them and use them folks.

After a day at home yesterday - JP working on her skinboat and me outback aerating the yard with the atlatl and darts, we took a hike on another part of the AT today.  Quiz for today:  What connections exist between Bowie and this rock?

About two years ago the navigation class that I was supposed to teach at our club's kayak class weekend was rained out.  So I put together several navigation related questions and posted them to the CPAKayaker list serve.  I was recently asked if I still had them around, so here they are:

 

Ok, so the navigation and rules of the road classes got washed out at Lake
Anna this year.  If you would have attended, you would know that aides to
navigation come in different colors:

Question #1

Cans, which mark the port side of channels, are green.
Nuns, which mark the starboard side of channels, are red.

Some aides are green and red, marking branching channels.

Aides that are white and red mark safe water.
Aides painted black and red mark isolated dangers.

Yellow is for special use.

But do you ever see blue on an aide for navigation?

Answer #1

Yes, those are the two applications of blue in the US.

One is the Francis Scott Key Buoy is shown at approx 39 degrees 13 min 30 sec lat x
76 31 30 long, just north of the spot where the key bridge crosses the Fort
McHenry channel.  It is labeled on most charts as N Bu R W, which means Nun,
Blue, Red, White. 

Question #2


When we go to paddle across a river or channel, or a lake, we generally pick
an object on the far shore to paddle toward.  If there is no wind and no
current, and we paddle straight, we will arrive at the object we picked via
the shortest distance from our starting point.  However, in real life things
like wind, current, waves, and other factors can cause us to paddle a course
that is not a straight line from start to finish.  One of the methods to
insure that you are paddling in a straight line to your destination is to
use ranges.

A range is when you can see one object at your destination point, and can
also see a second object DIRECTLY behind the first object.  As long as you
are able to paddle toward the first object and keep the second object lined
up directly behind the first, you are paddling the shortest possible course
to your destination.  For example, let us say that you want to paddle across
the Potomac river from the Maryland side.  On the Virginia shore you can see
a white house along the shore. By shifting a few yards one way or anoher you
can get a water tower to line up directly behind the house.  Now as long as
you paddle your kayak so that the water tower stays directly behind the
white house you will be paddling the shortest course to the white house from
your starting position on the Maryland side.  The farther the distance
between the two objects that you are using as ranges, the greater accuracy
you will be able to maintain on your paddle toward your destination.  If the
water tower is only 200 feet behind the white house, your course will not be
as accurate as it would be if the water tower was 1000 feet behind the white
house.  When picking objects to use as ranges, try to pick one object at
your destination point and try to find an object on the horizon to use as
your second point.  This may mean shifting your starting position a hundred
feet one way or another to begin with, but it will shorten your overall
trip.  Near objects can be buildings, docks, or a tree.  Far objects can be
radio towers, water towers, smokestacks, or the notch of two hills or mountains.

When using a range, you will sometimes find that the second object will
appear to move out from behind the first object you are sighting on for your
range.  This means that you are no longer on the direct route to your first
object and need to correct your course.  In our example of crossing the
Potomac from Maryland we made a range of a white house with a water tower
that lined up directly behind the house.  If, as we paddle across toward our
destination, the water tower appears to move out to the right of the house,
do we need to paddle to the left or to the right to correct our course and
get the house to line up with the water tower again?

Answer #2


To get back in line with the range that we have established using the house
and water tower we would have to paddle to the left.  This would put us back
in line with the two objects we are using for a range and allow us to
continue our paddle as planned.  Our drifting out of alignment was probably
due to wind, waves, or current.  To stay in alignment with the range
objects, we will need to angle to kayak slightly into what is causing us to
drift.  Your kayak will now be pointing slightly to one side of the range
objects, but you will be travelling toward them.  The angle between the
direction the kayak is pointing, and the direction of your intended course
is called the ferry angle, which you may have seen discussed in some of the
posts about Navigation Question #2 last week. 

QUESTION #3:

Before setting out on your trip, you can actually calculate what the ferry
angle would be in general situations.

Let's say that the potomac crossing is six miles.  You can paddle at 3 miles
per hour.  You know that the incoming tide will have a predicted speed of 1
mile per hour during the time you will be on the water. 

Take a compass sighting on the range made by the two range objects we
selected by using your deck compass.  Point the kayak at the range.  Read
the compass.  Let's say the compass heading is 270 degrees.  Note that this
compass reading is when you, the house, and the water tower are all in line
with each other and the boat is pointing at the range objects.

Paddling at 3 miles per hour, you will be on the water for two hours. 

The current, at 1 mile per hour, will push you upstream (directly north) two
miles if it takes you two hours to do the crossing. 

If you start paddling directly toward your range objects you will end up in
Virginia two miles upstream of your range objects, and have to paddle two
more miles than your planned six to reach the Va. landing point.  You need
to compensate for the tidal current.

On your chart, draw a line from your Md. starting point (label this point A)
through the two range objects you will use.  Where the line intersects the
Va shore label this point B.   Draw a line perpendicular to line AB through
point B.  Measure this line to find a point two miles south of your line AB
across the potomac.  Label this new 2 mile point as C.  You now have two
sides of a triangle.  Complete the triangle by drawing a line from C to A.
The angle that is between the lines AB and AC is your ferry angle.  This is
the angle that you need to keep the bow of the kayak pointed in to cross the
potomac along your intended course of AB. 

This angle is slightly less than 20 degrees.  Round it off to 20, since
compass navigation in a kayak is rarely more accurate than plus or minus
five degrees.  Your course from Md to VA along the range line was 270
degrees by the compass reading.  Subtract 20 degrees from this to get 250
degrees.  As you paddle across the potomac, you should keep your boat angled
to read 250 degrees on your deck compass, and keep your boat in line with
the two range objects.  This will get you across along the line AB. 

That's the theory.  Real life is a little different.  Wind, tide, current,
and waves vary and our 250 degree heading is a best guess before starting
out.  Still,  I'd rather use a best guess than find myself two miles away
from my intended landing point!  In practice, I always try to end up
slightly "above" my intended landing point.  In this case, since the current
is pushing me toward the north, I'd like to end up over near the Virginia
shore slightly south of my landing point and be able to drift down easily to
it, than paddle against the tide.  This is particularly important if
paddling against wind and waves.  It's demoralizing to make a bumpy crossing
only to find that you now have to paddle against the wind and waves to get
to where you were trying to head in the first place.  As you paddle across,
keep an eye on your compass and the range, and adjust your angle and
paddling speed as needed.

Back to theory.  Given:

Compass heading to the va shore from md is 270.
It is  6 miles from MD to Va.
Paddling speed is 3 mph.
There will be incoming tide for the first 1/2 of the trip.
Incoming tide will be 0.5 mph heading north.
There will be outgoing tide for second 1/2 of the trip. 
Outgoing tide will be 1 mph heading south.

What should your compass read as you paddle across?

Hint #1:  The range will tell you when to change.


Answer #3

On your chart, draw a line from your starting point in Maryland to your
anticipated landing point on the VA shore.  This should line up with the
house and water tower we are using as ranges.  This is line AB, A being on
the Md shore.

Since the tidal current will change half way through the trip, mark a point
halfway along this line. This is point C.

For the first half of the trip, the tidal current is going upstream at 0.5
mph. 
Trip length is 6 miles / 3 miles per hour = 2 hours.
0.5 mph current x 1 hour (halfway) = 1/2 mile for how far the tidal current
will try to push you upstream.

Draw a line perpendicular to your planned range route from the halfway point.
Measures off 1/2 mile DOWNSTREAM along this line.
Mark this point.  This is point D.

Use your NAVAID to calculate course along this line from point A to point D.
This would be your ferry angle compass reading to hold for the first half of
your trip.
It should be about 260 degrees.

The tidal curren will change at the time you are in mid river and begin
flowing out. 
It will flow out at 1 mph.

From point B on the Md shore, draw a line perpendicular to line AB.

Outgoing tide of 1 mph x 3 miles distance / 3 mph paddling speed = 1 mile
current push downstream. 
You will need to compensate for the current by aiming 1 mile upstream FROM
YOUR POSITION AT THE TIME THE CURRENT CHANGES. This is important.
Let's assume your have done all your calculations and paddling correctly,
and that the current for the first half of the trip was as predicted.  You
should be at point C in your kayak.

Measure 1 mile upstream from point B along the line perpendicular to AB.
Call this point E.  Draw a line from point C to point E.  This is your new
ferry angle course.  It should be about 290 degrees.

In theory, you will paddle off the Md shore using a ferry angle compass
reading of about 260.  Halfway through your trip, when the tide changes, you
will change your ferry angle course to be 290 degrees, and end up at your
destination on the VA side.

Why did we do this navigation calculation along a route that had a range?

The range will act as a double check for our ferry angle caculations and
will tell us when the current changes.  As you paddle along, keep checking
the range.  Adjust your planned ferry angle to keep the range in line.  This
will compensate for errors or variations in the tidal current data, and wind
effects.  As you reach the point where the current begins to reverse, there
will be a period of slack current, and then the reverse current will begin
to occurr.  Keeping your range will allow you to compensate for these periods. 

As a good general rule, never rely on only one way to navigate.  In this
case, the range acts as backup to the ferry angle calculations you made.

Question #4


How fast do you go in your kayak?  This is a question to ask whether you are
racing or just out for a casual paddle.  If you know the answer to this
question, then you will start to be able to apply the principles of dead
reckoning to your kayak trip planniing and navigation.

In marine navigation, distance is measured in nautical miles (NM), which are
6,076 feet, or about 15% longer than a statuate mile as measured in your
car.  Time is measured in minutes and hours, and speed is measured in knots.
One knot equals a speed of one nautical mile per hour.  The formula looks
like this:

speed = distance/time

If you paddle 8 nautical miles in 4 hours, your speed would be:

8/4 = 2 knots.

How can you figure out your typical paddling speed?  Some of us keep logs of
our kayak trips, where we record the duration of the trip, and the miles
that we covered.  You can measure the miles off of a chart after you get
home.  You can keep track of the duration by using the stop watch function
on most digital watches.  Whenever Jenny and I paddle, we start our
stopwatch functions when we are both on the water at the launch point.  We
keep the watches running through lunch stops, water, and shore breaks.  When
we return to the launch point at the end of the day we stop the watches.
Over several trips this gives us data that may look like this:

5/14/00  10 miles  4.3 hours
6/3/00   14.5      7.0
6/11/00  11.0      4.5

Over these three trips, we have paddled 35.5 miles in 15.8 hours.  Our
average speed, including breaks, was 35.5/15.8 = 2.25 miles per hour, or 2.3
knots.  As we add more trips to the list, our calculation of average speed
for the two of us paddling becomes more accurate.  If you know your average
speed you can figure out how long it will take you to paddle somewhere. Say
you want to launch from your favorite put in and paddle across to a county
park.  You measure the distance from a chart, and it is 10 NM.  10 NM x 2
(you have to get home) = 20 NM.  20/2.3 = 8.7 hours of paddling.  Can you
paddle for almost 9 hours?  If not, doing this bit of math just saved you
from a really long paddle back to your launch point. 

Let's say you shorten the trip to a closer lunch spot that is only 6 miles
away.  Roundtrip is now 12 miles, and will take 12/2.3 = 5.2 hours.  This
looks reasonable for many people.  It's good to know the estimated duration
of a trip before you start out for several reasons.  Of course, there are
the dinner reservations you made, and perhaps you prefer to get back to the
car before dark. 

If you keep track of your lunch break times, you can add another important
bit of data to your personal paddling navigation.  Let's assume that on the
three trips listed above each had a 30 minute lunch, and no shore breaks.
Our on-water speed is now:

35.5/14.3 = 2.5 knots.

What can you do with this information?  Remember problem #3 where we wanted
to paddle across a 6 mile wide river and we knew our paddling speed was 3
knots?  If you know your on-water paddling speed you can figure out how long
it will take to get from one point to a second point.  Note that this
on-water speed includes any breaks you take on the water to drink, rest, etc. 

Paddling from Pier 7 to the Thomas Point Lighthouse is about 7 NM (don't
quote me on that).  If my on-water paddling speed is 2.5 knots, and sunset
is at 7:00 pm, when do I need to launch in order to get back by sunset?
(Don't worry about currents or wind)

Answer #4


To find the answer:

7 NM x 2 (it's a round trip) = 14 NM total
2.5 knot speed

14/2.5 = 5.6 hours

5.6 hours = 5 hours 36 min.

7pm - 5 hours 36 min  = 1:24 pm.

You need to launch by 1:24 pm.

Question #5


In Question #4 I explained how to use the speed/distance/time formula to
figure out how long a trip, or segment of a trip would be.  This information
can also be used to help you figure out where you are at any point on your trip.

If you have an typical paddling speed on the water of 3 knots, you know that
you will probably travel 3 nautical miles in one hour.  So if you and a
friend launched your kayaks from Pier 7 on the South River and paddled down
the river for an hour, you can figure that you have probably paddled 3
nautical miles.  This is a ballpark estimate of your location on the river.
If you know what the tidal current is doing at the time of your trip, you
can increase the accuracy of your estimated position by adding or
subtracting the tidal current velocity to your paddling speed.  So, if the
current is going out (ebbing) at 1/2 knot at the time you are paddling, you
will have travelled this distance:

 1 hour x (3 knots paddling + 0.5 knots current) = 3.5 nautical miles from
your starting point.

 If the current was coming in (flooding), your distance would be figured as:

 1 hour x (3 knots paddling - 0.5 knots) =  2.5 nautical miles from your
starting point. 

If you have a record in your log book of the effects of wind on your
paddling speed, you can add or subtract the wind effect in these
calculations.  Note that a 15 knot wind does not move you in your kayak at
15 knots!  Let's say your records show that a 20 knot headwind reduces your
on water speed to 1.5 knots.  Our distance paddled for one hour with a 20
knot head wind and an ebb tide of 0.5 knots would be:

1 hour x (1.5 knots paddling speed in 20 knots headwind + 0.5 knots current)
= 2 nautical miles. 

This system works well on a small river or following a shoreline, but it is
still only an estimate of how far you have travelled, and where you may be.
When I wrote about using a range to help cross a river, I also used a
compass heading.  The two methods, which work independantly of each other,
give me two different ways of navigating on my course.  The same idea of two
independant methods also works when trying to figure out where you are.
Method #1 is the speed/distance/time formula discussed above.  Method #2 is
to determine your position by the use of compass bearing fixes.

Let's say you've been paddling along, and slowly realize that you're not
quite sure where you are.  You know your speed/time/distance information,
but that only tells you how far you have paddled, not in which direction.
You look around.  You see a lighthouse, a green navigation aid marked "41"
and a green aide marked "1MH".  Assuming you have a deck mounted compass,
point your boat at each item and note the reading on your compass.  This is
your bearing to each item.  You have:

lighthouse:  240 degrees
green 41:  90 degrees
green 1MH:  0 degrees

Get out your chart plotting device.  You should be able to figure out
roughly where you are on the chart and find the three objects on the chart
that you see around you.  If a person was on the lighthouse looking at you,
they would read a compass bearing that is called the recipricol to the one
you read looking at the lighthouse.  Think of it as the reverse of the
number that you read when looking at the object.  To find a recipricol, add
or subtract 180 from your bearing.  You add 180 if the bearing is less than
180, and subtract 180 if it is more than 180.  (Frankly, I just think of it
as what is on the opposite side of the compass from me).  Here's the
recipricols:

lighthouse recipricol:  240 - 180 = 60 degrees
green 41 recipricol:  90 + 180 = 270 degrees. 
green 1MH recipricol:  0 + 180 = 180 degrees

Now, you can draw a line from each of these objects using the recipricols.
If you do this, the three lines from the objects should form a triangle
inside the larger triangle formed by the three objects.  You are probably
somewhere inside or very near that small triangle.  The more accurately you
do each of the steps involved (taking the bearings, drawing the lines) the
smaller the triangle will be, and the better idea you will have of exactly
where you are.  Here are some hints on how to get better accuracy:

1.  Whenever possible, pick objects that surround you.  In this example, we
had objects north, east, and southwest of the kayaker.  If you don't have
this, try to pick objects that are not all close to each other.  The farther
the objects are from each other the better your accuracy.

2.  Pick objects that are discrete.  Pick navigation aides, radio towers,
water towers, the center of bridges, etc that are shown on your chart.  Try
not to use hills (hard to define where the top is on the chart), points of
land (if you're really lost, they often all look the same - especially in
the Chesapeake), or groups of buildings.

3.  The farther the object is from you, the greater the accuracy of your
compass reading. 

4.  Take all of your bearings, then do the math and chartwork.  This will
help keep drift error smaller than if you take one bearing, calculate and
plot the recipricol, and then do the next.  Between bearings you may be
drifting.

Now, remember I mentioned using two methods independantly?  Is the location
you just plotted in rough agreement with your speed/distance/time
calculation?  If you plot your location as 10 miles from your start point,
and your speed/distance/time calculation says you've travelled 3 miles, one
of the two is definitly out of wack.  Recheck each.  If they still do not
agree, and the difference could not reasonably be due to wind or current
effect,  you are not out of luck yet.  There is at least one thing you and
and your buddy in your kayaks can do to try and figure out where you are.
Assume you each have only a compass, chart, plotter or Navaid, and don't
want to paddle any more than you have to in order to determine your
position.  What can you do?

Extra credit for the experienced navigator and navigation geek:  what is the
height of the lighthouse?

Answer #5


Possible things to do to verify the accuracy of your position fix:

1.  Get both boats side by side, about 3 feet apart, and both aimed at one
of the objects on which you can take bearings.  Each paddler should
independantly read their boats' compass.  Do the two numbers agree to within
5 degrees?  Repeat for the other two bearing objects.  Do the bearings from
one of the compasses make more sense than from the other compass?  If so, it
is likely that the one compass is in error - either it is broken, or there
are ferrous or electrical items packed nearby it in the boat that are
affecting its performance. 

2.  Are both charts the same?  Jenny and I often paddle with two different
makes of charts or maps.  Often one chart will show details that the other
does not.  For instance, we have used marine charts in conjunction with MDE
fishing charts; or marine charts in conjunction with topographic maps.
Also, check the reference dates of the charts.  Use the newer chart!

3.  Put a greater reliance on the objects that can change the least.
Lighthouses are rarely relocated by man or mother nature.  On the other
hand, buoys and day marks may be relocated by man, ice, or storms.  Brian
Blankenship and I paddled the Core Banks area of North Carolina several
weeks after the hurricane passed through the area and noticed that many
bouys were well off their charted positions, if they could be found at all.
In question #5, I would place a greater reliance on the location of the
lighthouse than any of the other bearing objects.


>
>Extra credit for the experienced navigator and navigation geek:  what is the
>height of the lighthouse?


52 feet.  There is only one spot on the bay where this combination of
lighthouse and navigational aides exist.

Three days before the weekend I had a choice to make - go to the kayak club trip planning meeting on Saturday, or go take advantage of the predicted 70 degree weekend temperatures and go backpacking.  When I learned the trip planning session was at noon on Saturday, which was going to deprive me of being outdoors both days (I had thought it was Saturday night) the decision to go backpacking was the obvious choice. 

 

I chose the loop formed by the AT trail over Cold Mountain and the Hotel Trail which comes back along the eastern side of Cold Mountain.  After the climb to the top of the mountain, the AT travels across about a mile of balds (wide grassy areas with no trees) with spectaular views. 

 

 

It was a great spot to eat lunch, read a book, and watch the scenery.  Unfortunately, it was also very sunny and I had just gotten a short haircut - and now had the first sunburn of the season.  A nice night in the hammock using the WM Apache bag and the CCF pad (High 72, low 59).  I had planned for the catabatic winds with my hammock pitch, and slept well.  A couple of sprinkles during the night, but not enough to wet things down.  Day two was an easy hike back out on the hotel trail, past a couple of possible future campsites.