How to Find Latitude and Longitude on a Nautical Chart

Any GPS receiver will find Latitude and Longitude along your sailing routes at any moment. But as a skipper, have you plotted this information onto a nautical chart to check your position? Boost your sailing navigation skills to the next level with this vital sailing skill!

Navigating with Latitude

Cartographers create a grid-like web on your navigation chart. Latitude lines run in a horizontal direction. Longitude lines run in a vertical direction. Imagine the earth, balanced on her axis without a tilt. Wrap a “belt” around the earth, divide it in two and you have the equator–birthplace of Latitude. Label the equator 0 degrees.

Latitude lines parallel the equator to the north or to the south. To plot Latitude to find out where you are, you measure how many degrees you are north or south of the equator. Latitude reaches a maximum of 90 degrees at both north and south poles. Always label Latitude N, if north of the equator, or S, if south of the equator.

In chart navigation, use the scales on the right or left side to find your Latitude. These scales are broken down into degrees, minutes and tenths of a minute, or degrees minutes and seconds. One degree of Latitude equals sixty minutes; one minute of Latitude equals sixty seconds. Here’s a simple way to remember this:

1 degree = 60 minutes.

1 minute = 60 seconds.

Navigating with Longitude

Return to your imaginary globe. To measure Longitude, you again divide the earth in half, but this time lengthwise. Locate Greenwich, England on your globe. Draw a line around the earth that intersects Greenwich and both north and south poles. Cartographers call this the Greenwich, or prime meridian–the birthplace of Longitude. Label the Greenwich meridian 0 degrees.

Longitude lines parallel the vertical Greenwich meridian to the east or to the west. To find longitude, you measure how many degrees you are east or west of the Greenwich meridian. Longitude reaches a maximum of 180 degrees on the other side of the earth, at the International dateline. You must label Longitude E, if east of Greenwich, or W, if west of Greenwich.

Use either the top or bottom of the chart to measure Longitude. Like Latitude, Longitude is broken down into degrees, minutes and tenths of minutes or degrees, minutes and seconds.

How to Convert Increments of Minutes

All nautical charts show minutes broken down into increments so that you can plot parts of a minute. For example, if your gps position shows 23-13N; 82-16W, there are no increments to worry about. But, if your gps position shows Latitude 23-13.278N; Longitude 82-16.786W, you have increments of minutes. Before you plot your position, round off increments to the closest tenth of a minute. Round off like this: Latitude 23-13.3N; Longitude 82-16.8W.

Look at the Latitude scales (right or left side) and Longitude scales (top or bottom) on your chart. Are minutes broken down into tenths or into seconds?

Some charts show degrees, minutes, and tenths of a minute. The minutes will be broken down into 10 small segments. Each small segment equals one-tenth of a minute. Other charts show degrees, minutes, and seconds of a minute. If your chart shows degrees, minutes, and seconds, you will need to multiply the “tenths” of a minute by 6. Follow this example:

GPS reading (with minutes rounded as described earlier): Latitude 23-13.3N; Longitude 82-16.8W.

Multiply the increment of Latitude minutes like this.3 X 6 = 18 seconds.

Multiply the increment of Longitude minutes like this.8 X 6 = 48 seconds.

Plot: Latitude 23 degrees, 13 minutes, 18 seconds; Longitude 82 degrees, 16 minutes, 48 seconds.

How to Plot Latitude and Longitude

Use a pair of dividers to plot your position by Lat and Long onto the chart. Read the degrees and minutes from your GPS. Find the closest degrees and whole minute of latitude on your GPS.

For example, for Latitude 23-13.3N, you would look for 23 degrees, 13 minutes on the right or left side scales on your navigation chart. Push one point of your dividers into the 13 minutes. Open up the other leg 3 small segments (three tenths), above the 13 minute mark. If your chart shows seconds instead of tenths, open up the other leg of your dividers 18 seconds (.3 X 6) above the 13 minute mark. Place a pencil mark where the dividers touch the exact Latitude.

Next, plot your Longitude. Use the same exact method to plot your Longitude. Make sure to use the top or bottom chart scales to plot your Longitude. When you’ve found your Longitude, place a pencil mark where the dividers touch the exact Longitude.

Find Your Exact Position

Align your parallel rules or any other straight edge so that the top long edge touches the Latitude pencil mark. Make the parallel rules or straight edge perpendicular so that when you draw in the Latitude line, it will be parallel to all other latitude lines. Draw a light pencil line across the body of the chart to a location close to where you marked the top or bottom Longitude scale.

Repeat this same method to align and draw in your Longitude line. Where the Longitude pencil line intersects the latitude pencil line shows your exact position. You should now have a cross. Place a dot where the two lines cross. Circle the dot. Erase the light lines drawn from the edges of the chart to clean up the chart and keep your plot neat.

Use these easy steps to find Latitude and Longitude on your nautical chart fast. With these sailing skills, you will be well on your way to become a confident sailing skipper-anywhere you choose to go sailing!

Sailing Navigation Secrets – Mark Your Nautical Chart With Magic Art!

Did you realize that you can make your chart easier to see, with less clutter? And that you can do this with simple office tools to save eye strain, make sailing navigation safer, and chart work easier? Use these easy steps for safer sailing navigation anywhere in the world.

Use “bright and bold” highlights to make vital chart symbols stand out.

Know exact locations of perfect anchorage spots before you arrive there.

Identify reliable depths compared to unreliable depths on your chart or plotter.

Tools You Will Need:


*Direction measuring instrument (parallel rules, Weems plotter).

*Yellow, orange, and blue highlighters.

*Colored blue, green, magenta pencils.

*Fine felt-tip pen.

*Scotch magic tape (permanent or removable.

Scan, Mark, and Protect Your Costly Charts

Master navigators always use a step by step process to plot their sailing routes, scan all along the sailing route for danger, and mark the most important spots like shoals, wrecks, emergency “pull-off-the-road” anchorages, and major aids to navigation that affect your sailing safety.

Follow these seven simple steps in the order shown anytime you plot a course for day sailing, cruising, or distance voyaging. It will keep you safe and you will have the confidence that you can see “at a glance” what lies ahead.

1. Use parallel rules or Weems plotter. Plot each course along your sailing route with light pressure with your pencil. Use light lines in this step. That way, if you need to erase, you can do this without effort or marring the chart.

2. Scan along each sailing course line to make sure the course does not cross over dangerous shoals or shallow depths. If it does, erase that leg and change it to a safer course or break it into two courses to avoid the hazard.

3. Use bright colored highlighters or colored pencils to make dangerous wrecks or important aids to navigation (buoys, lights, or landmarks) near the course.

4. Look for deep water pockets off the course line where you could anchor for rest or in an emergency. Make shoal depth contours stand out by tracing over them with a dark blue colored pencil (or similar marker).

5. Stay in water with a depth at least twice your draft. Coastal charts often show water depth contour lines in six foot increments that begin at 30 feet. That means the next depth contour would be 24 feet, then 18 feet, 12 feet, and 6 feet. Mark the outermost depth contour that’s equal to at least 2X your maximum draft.


If your draft is 5 feet, you should mark the 12 foot (or higher) contour curve. Set your depth sounder, GPS, or chart plotter alarm to trigger at that depth. This gives you time to turn the boat toward deeper water.

6. Check each course again for dangers. Recheck each plotted course to make sure the direction marked agrees with the direction indicated by your plotting tool. When satisfied, go to the final step.

7. Run a length of tape over the top of each of the light penciled course lines. Run your fingers over it several times to make sure it adheres to the chart surface. Lay a straight edge on top of the tape and darken in each course line with the felt tip marker. This makes your courses stand out in any light or weather condition.

Use your pencil to write the course in degrees magnet on top and the length of the course leg on the bottom of the line. When you label, write onto the tape. This protects the paper chart and the tape surface can be written on and erased as needed.

  1. Captain John’s Sailing Navigation Tip:
    How do you remove the tape when you’re done with the cruise? Use one of these two fast methods. Scotch makes a ‘removable magic tape’ brand. It isn’t as sticky but works well on a dry surface. Or, heat the edge of a blunt kitchen knife with a lighter. Run the knife along the tape and peel as you go. Keep the knife edge warm for best results.

Beware of Spotty Soundings!

Chart plotters fall far short of nautical charts when it comes to detailed soundings. Their small screen real estate forces the manufacturers to sacrifice detail in order to keep the screen uncluttered. This reason alone should be enough to convince any prudent skipper to carry navigational charts.

Scan your chart for signs of inconsistent or scattered soundings. Large gaps between soundings warn that this area hasn’t been surveyed well enough for safe sailing navigation. Keep clear of areas with spotty, inconsistent soundings to avoid grounding or hitting an underwater, uncharted obstruction.

Spoil areas (also called a fish haven or spoil bank) are where debris like garbage, old cars and trucks, and construction site material are dumped. Theses depths change all the time, so they will never be shown. Stay clear to stay safe!

Now you know the fast, easy way to get your chart set up for safe sailing navigation to save you time and effort once you go sailing.

Nautical Star Tattoos The History, Meaning And Symbolism – What A Strange Mix!

The history, meaning and symbolism of nautical star tattoos is

a hotly debated topic. Today many different groups have

adopted the Nautical star tattoo as a symbol for their own

movement and they have all ascribed their own meaning and

history to the symbol. Thus has lead to a wide

disagreement as the the meaning of the tattoo.Historically

most everyone agrees that Sailors were the first people to get

nautical star tattoos. In fact the very word nautical

relates back to sailing. So this connection has been

pretty firmly established. Most people would agree the

sailors were a pretty superstitious group historically and

sailor lore abounds with superstitious and fantastical stories

of life and death and being lost at sea. Early on

sailors navigated by the stars at night and the north star

became the symbol for finding ones way home. Once you

know where the north star is you can point your ship in the

right direction to get home. So the star became a symbol

for finding ones way home or more symbolically even finding

ones path in life. Therefore many sailors would tattoo

nautical stars on their forearms as a good luck symbol in

hopes of returning home.

However their modern day meaning is a more debated topic.

Many believe that groups including gay and lesbians, punk

rockers and those in the military have adopted the nautical

star tattoo as a very important symbol. The diversity of

these three groups has lead many to argue the meaning of their


For the military the connection is pretty obviously point

back to the early sailors and the symbolism and meaning is the

same as the early sailors. Many military people get a

nautical star tattoo as a symbol for finding ones path home

safely. Of course this can also include more

symbolically just finding ones way in life.

Here is a quote we found from a member of the armed

services and his interpretation of the tattoo:

“I am in the United States Army, an MP who searched towns

and villages for Al Quida and insurgents. I was in Iraq for 1

year. I have a red and black nautical star on my wrist. The

reason I got it was because when I was out there, I felt it

was a guide to guide me home to my family safely. I got it so

that it would remind me that I am going to make it to see my

son grow up. I am not gay, it doesn’t matter what you believe

it represents, it means something different for everyone. Out

in the desert, I would look up at the stars and think about

home. So anyone can think what they want to, that is what it

means to me. “

Punk rockers have also adopted this as a popular symbol to

have tattooed. The punk movement traces its history and

use of the nautical star tattoo back to Sailor Jerry.

Sailor Jerry is historically one one of the most famous tattoo

artists ever. He was well known for his innovative and

“cool” designs. Punks have taken this symbol and it has

very much the same meaning of finding one way in life.

Being the rugged individualists type Punks are drawing to the

symbolism of true north and finding one own unique way in

life. So the Nautical star has become a symbol for this.

You see many punk bands that have full sleeve tattoos

typically incorporate nautical star tattoos either on their

elbows or elsewhere.

The lesbian and gay connection is the one that does not

seem so obvious at first. Historically back in the

1940’s and 50’s when alternative lifestyles were not the norm

and often women had to hide their alternative choices they

would sport a hidden nautical star. Often they would get

the star tattoo done on the inside of their wrist where it

could easily be hidden by a watch during the day but shown off

in the evening when out on the town. Today many lesbians

where the nautical star tattoo to show their connection with

their early pioneering sisters. Here is a little

evidence to support my points.

“Here’s the passage (with some pieces dropped) from “Boots

of Leather, Slippers of Gold: The History of a Lesbian

Community” by Elizabeth Lapovsky Kennedy and Madeilne D. Davis

copyright 1993 p. 189.

(talking about the 1940’s and 1950’s):

“…During this same time period, the cultural push to be

identified as lesbians- or at least different- all the time

was so powerful that it generated a new form of identification

among the tough bar lesbians: a star tattoo on the top of the

wrist, which was usually covered by a watch. This was the

first symbol of community identity that did not rely on

butch-fem imagery. We can trace this phenomenon back to an

evening of revelry in the late 1950’s, when a few butches

trooped over to “Dirty Dick’s” tattoo parlor on Chippewa

Street and had the tiny blue five-pointed star put on their

wrists. Later, some of the fems of this group also go the idea

one night and did it…The community views the tattoo as a

definite mark of identification…”the Buffalo police knew

[that] the people that had the stars on their wrist were

lesbians and they had their names and so forth. That it was an

identity thing with the gay community, with the lesbian

community”. The fact that the star tattoo was created by those

who were firmly into roles, in fact by the group that was

considered the butchy butches and their fems, suggest that the

force to assert lesbian identity was strong enough to break

through the existing traditions of boldness based in butch-fem

roles. The stars presage the methods of identity created by

gay liberation. In fact, the mark has become something of a

tradition in local circles and has seen a revival since the


This meaning of the symbol has of course created a lot of

problems and arguments among the other two groups of bearers

of nautical stars. Most puck and military people do not

want to have a nautical star that points back to anything from

the lesbian movement so many will say that there is no

connection there and this is false.

Here is a quote from another armed forces member about the

symbolism of the nautical star among the gay community:

“This “gay symbol” is a load of hooey that someone made up

VERY recently. The nautical star tattoo has been around nearly

as long as tattooing itself. The late Celts (or early Irish,

depending on your view of World History) were said to have

been the first to have the tattoos, although evidence of it

being used on ships in Spain has been found pre-dating the

Irish claim.

As a Marine, it’s a very commonplace symbol amongst us if

we have been part of a Boat Raid company, red for port, green

for starboard on varying parts of the body. On ship, I saw

about a million different variations on the Sailors I was was

serving with, obviously harking back to the sailor roots.”

Here is a quote from a punk rocker and his feelings about

the symbolism of the tattoo:

“what idiots..even the military boys dont know what it

really means….JUST SO YOU ALL KNOW!!!!!it was used by OLD

sailors.. and the symbol represents North on a Map …and it

is the North Star the sailors would use it as a baring to get

home….you can find it on Really really old maps and old navy

vessels… Punk Rock.. well we use it because we can and

because Sailor Jerry made the coolest tattoos who started

putting them on everyone.. my grandfather even had one thus

being used as a traditional icon”

It just goes to show that when the same powerful symbol is

used over and over again over decades of time it can taken on

very different meanings for different groups. So all of

those that you see sporting a nautical star tattoo might not

all have the same interpretation of its symbolism.

So do you have a nautical star tattoo or think about

getting one in the future? Which meaning of the symbol

will you get the nautical star for? As long as you know

what the symbolism behind the star is for and you have gotten

it for the right reason to either support the lesbian movement

or as a symbol to finding your way!