Safe Navigation Starts with Accurate Charts

October 30, 2016

12327_lowrescroppedThe 2016 TrawlerFest boatshow and seminar series recently wrapped up in Bay Bridge, Maryland. For those who missed it, Bob Sweet presented a mini-course style seminar focused on helping recreational mariners—whether inexperienced or “old salts”—confidently plan and safely navigate while on the water.

Sweet breaks down the navigation process into three distinct phases, as follows:

  • PHASE 1 – Plan: Pre-check safe paths
  • PHASE 2 – Navigate: Follow pre-checked paths
  • PHASE 3 – Check: Verify where you think you are


Key Takeaways

In his mini-course, Sweet walks through each phase of the navigation process, providing useful tips, clear examples, and helpful formulas. He offers a wealth of information. In the end, he offers this reminder:

Remember above all else even when everything else fails, there are three tools that won’t let you down: 1) your eyes and other senses, 2) your compass, and 3) your paper charts. It pays to know how to use them.

In this blog, we’ll take a high-level look at Sweet’s advice on how and when to use paper charts.


The Importance of Paper Charts


Sweet recommends using paper charts for planning because of their wide view and detailed information. He explains that added information on printed charts, which does not appear on digital charts, is critical when determining and prequalifying safe paths to navigate.

When you are planning a leg to navigate on the water, you are pre-qualifying that leg to be clear of various fixed dangers, both above and below the surface of the water.

Charts use a variety of symbols and notations to alert you to depths, bottom type, and hazards.

When prequalifying your paths, you should always use the most up-to-date charts available.



Recall that your job during the navigation phase is to carefully follow the paths you prequalified during the planning phase. For navigating, Sweet says digital charts are a good choice.

The chart details are less of an issue while navigating as long as you stay on the prequalified paths.

GPS (rather than a chart) is the main tool for navigation.

While underway, your GPS receiver determines your position with a high degree of precision based on the signals it receives from satellites. Your receiver then computes position, direction and speed over ground, and bearing and distance to waypoints you store and select in your GPS.



Be warned! Even though you’ll be using GPS and digital charts during navigation, you still need to verify that you really are where you need to be.

This phase is critical. You must verify your position, using a combination of your eyes, independent sensors such as radar—and paper charts.

Your GPS is accurate but not infallible. Not only that, you could have incorrectly entered some of the information into your GPS. It’s just a machine doing what you tell it to do… assuming that it is working properly. Just about every seasoned boater has had an experience with a misbehaving or suspect GPS at least once. Checking says you use your eyes and other resources to make sure you are where you think you are.


Sweet offers the following rule of thumb: 

You should be able to put your finger on your present location on a paper chart within 10 seconds at any time. This says two things. One, you have charts and they are close by. And two, you have been keeping track of your location and checking it.

Boston Light: America’s First Lighthouse Marks 300th Anniversary

October 6, 2016


bostonlightBoston Light, the country’s first lighthouse, was built 300 years ago on Little Brewster Island, Massachusetts. And she’s been guiding mariners into Boston Harbor ever since.


A Historical Treasure
First lit by candle on September 14, 1716, the original lighthouse structure was a rubblestone tower about 60 feet high.

 Over three centuries, Boston Light has undergone a multitude of repairs and renovations. She has been damaged not only by fires and storms, but also by war. During the Revolutionary War, the lighthouse was burned twice by patriot troops and was ultimately torched and destroyed by British forces as they left Boston in 1776.

In 1783, Massachusetts rebuilt Boston Light—this time as 74-foot high tower, lit by fish oil lamps.

In 1948, under the management of the Coast Guard, Boston Light was converted to electrical power. Today, she is equipped with a 1,800,000 candlepower light that can be seen from 27 nautical miles away.

In 1964, Boston Light was designated as a National Historic Landmark.

In 1989, Congress passed legislation requiring the station to be permanently staffed, making Boston Light the only remaining manned lighthouse in America. Coast Guard Auxiliarist Sally Snowman has been serving as the Boston Lighthouse keeper since 2003. She is the 70th keeper (and the first female) to hold the position.


Aid to Navigation
Boston Light is the oldest Aid to Navigation (ATON) in America. Today, the Coast Guard ATON system—which enables navigators to determine their position, chart a safe course and steer clear of hazards—has grown to include more than 48,000 federal buoys, beacons, and electronic aids.

“More than 73 million Americans are involved in maritime commerce, commercial fishing and recreational boating on our waterways, and we help them to get home safely,” said Capt. Scott J. Smith, the chief of the Coast Guard Office of Navigation Systems. “Our vast Aids to Navigation system started with the Boston Lighthouse and we celebrate its enduring contribution to our nation, our economy and our maritime heritage.”

Happy 300th Anniversary, Boston Light!

It’s Hurricane Season—Be Prepared!

September 29, 2016

Part 3: Practicing Preparedness

Throughout the hurricane season, which runs through November 30, it’s important to increase awareness, pay attention to news and emergency alerts, and know what to do before, during and after a hurricane. Learn how to prepare.

Boater Safety
For boaters, hurricane preparedness requires extra diligence—and extra steps. Here are some tips and resources from the U.S. Coast Guard:

  • Check marine weather: Check the weather each and every time you head out and continue to monitor it throughout your time on the water.
  • Get the Coast Guard Mobile AppDesigned for boaters, this app lets you check the weather at nearby NOAA buoys, including wind speed and directions, along with wave height.
  • In the event of a hurricane watch: If you have a boat, review your marina’s hurricane plan and secure your boat. This might mean taking your boat out of the water and strapping it down on shore or ensuring it is properly equipped to ride out the storm at the marina.


Hurricane Tracking Charts
OceanGrafix offers a variety of hurricane tracking charts that let you track and record storms throughout the hurricane season. Select the hurricane chart that’s right for you.

GPS Jamming: A Potential Threat to Maritime Navigation

June 10, 2016

Maritime navigation has made huge strides in recent years. One innovation in particular, GPS, has made navigation easier than ever. As a result, many mariners are now conditioned to expect excellent GPS performance.

That’s fine – to a certain point. But here’s a new twist. If a mariner relies solely on electronic charts for navigation, what’s the fallback position when their electronic navigation fails, or worse yet, is purposely jammed? On Jan. 19, 2016, the Coast Guard addressed this issue:

“This past summer, multiple outbound vessels from a non-U.S. port suddenly lost GPS signal reception. The net effect was various alarms and a loss of GPS input to the ship’s surface search radar, gyro units and Electronic Chart Display & Information System, resulting in no GPS data for position fixing, radar over ground speed inputs, gyro speed input and loss of collision avoidance capabilities on the radar display.”

According to a recent paper by The General Lighthouse Authorities of the United Kingdom and Ireland, GPS signals measured at the surface of the earth are quite weak. This means the system is vulnerable to interference and jamming, resulting in possible denial of service.

Electronic Navigation: Not under your control

It’s important to remember that the quality and reliability of electronic navigation is not entirely under the control of the mariner, no matter how diligently hardware/software upgrades are implemented:

“A GPS signal can be disrupted for a variety of reasons, including the illegal use of a GPS jammer. Indicators of GPS compromise include intermittent signal, no signal and/or incorrect signal.”

Several methods have been used to disable, confuse or otherwise render a GPS tracking device useless. One method is the use of a GPS ‘spoofing’ gadget – a device that sends a fake radio signal that overrides the GPS signal and reports a fake location. These are not only illegal, but can be dangerous to other GPS users.

Best practice: be equipped with both printed charts and GPS

Here at Oceangrafix, we agree with the Coast Guard. Electronic navigation is a great tool for mariners. But if the threat of jammed GPS exists, relying solely on electronic navigation is not a best practice by any means. Digitally updated, print-on-demand charts from Oceangrafix can’t be jammed, compromised, or otherwise manipulated. We believe that conscientious mariners will invest in—and use—both options to ensure safe navigation.

It’s Hurricane Season—Be Prepared!

May 17, 2016

Part 2: The 2016 Hurricane Forecast

Spring is hurricane season. Some years, Mother Nature delivers widespread destruction (think Katrina in 2005); other years, there are few, if any, landfalls. What does this year’s storm season have in store?

This Year’s Forecast

Statistically, there is no direct correlation between the number of storms or hurricanes and U.S. landfalls in any given season. According to the 2016 Atlantic hurricane season forecast released by Colorado State University, a total of 12 named storms, five hurricanes, and two major hurricanes are expected this season. Some of these storms could hit the US mainland, but landfalls are impossible to predict with any accuracy. As a point of comparison, each year for the past 30 years there has been an average of 12 named storms, six hurricanes and three major hurricanes.

Be Prepared!

Hurricane Preparedness Week (May 15-21, 2016) is your time to prepare for a potential land-falling tropical storm or hurricane. NOAA offers daily tips on how to best prepare for hurricane season. Share these tips with your friends and family to ensure that they’re prepared as well. Remember: even areas well away from the coastline can be threatened by widespread flooding, powerful winds, and tornadoes.

Along with earthquakes, hurricanes are nature’s most powerful and destructive phenomena. If you live in an area prone to hurricanes, you need to be prepared. Given a hurricane’s potential for destruction, it’s best to be prepared for the worst while hoping for the best.

It’s Hurricane Season—Be Prepared!

May 16, 2016

Part 1: Learning More about Hurricane Forecasting

Every spring, the hurricane season descends upon us again. Here are two ways you can learn more about the science of hurricane forecasting and tracking.

NOAA’s Hurricane Awareness Tour

Do you live on or near the Gulf coast? Then you’ll want to attend NOAA’s hurricane tour of five U.S. Gulf coastal cities. The tour will include a U.S. Air Force Reserve WC-130J hurricane hunter aircraft and the NOAA G-IV aircraft, both of which are used in hurricane forecasting. The tour itinerary includes:

  • Mon, May 16: San Antonio Int’l Airport, San Antonio, TX, 2:30pm to 5:00pm
  • Tues, May 17: Scholes Intl. Airport, Galveston, TX, 2:30pm to 5:00pm
  • Wed, May 18: Lakefront Airport, New Orleans, LA, 2:30pm to 5:00pm
  • Thu, May 19: Mobile Downtown Airport, Mobile, AL, 2:30pm to 4:30pm
  • Fri, May 20: Naples Municipal Airport, Naples, FL, 2:30pm to 5:00pm

Visit this website for more details:

Hurricane Tracking Charts

Are you interested in following the progress of this year’s tropical storms? Hurricane tracking charts allow armchair storm chasers and nautical enthusiasts to track and record storm progress throughout the hurricane season. Obtain the appropriate chart and track the storms right along with the experts!

How Do Paper Charts Get Updated?

May 8, 2016

The Process of Updating Paper Charts
Despite much advancement in navigational technology, the U.S. Coast Guard and NOAA continue to stress the importance of having accurate paper charts on board. Problems such as electronic failure or other complications can and do occur, often at the most inopportune time. When the unexpected happens, NOAA paper charts—long considered the standard—can serve as important insurance. Yet charts have to be accurate to provide value, and they soon become outdated. Unfortunately, many mariners do not fully understand how to keep their charts up-to-date. NOAA works diligently to keep its charts current. Corrections come from three main sources:

Source 1: NOAA performs surveys in oceans, bays, lakes and rivers to monitor changes to depth and shoreline and to locate and disprove Dangers to Navigation (i.e., wrecks, rocks and obstructions). NOAA also receives the latest channel surveys from the Army Corps of Engineers and the latest bridge information from the Coast Guard. And, some United States Power Squadrons collect on-water observations through their Adopt-a-Chart program and submit them to NOAA.

Source 2: Notice to Mariners. Each week, the National Geospatial-Intelligence Agency (NGA) issues what’s called the Notice to Mariners. They contain important information that should be added to existing charts manually, thus bringing them up-to-date. Commercial mariners are fully aware of the Notice to Mariners because by law they are required to carry fully up-to-date NOAA navigational charts at all times.

Source 3: Local Notice to Mariners. The nine district U.S. Coast Guard offices issue the Local Notice to Mariners (LNMs) each week. LNMs provide marine safety information that keeps boaters informed about recent changes—such as a relocated navigation aid or a new obstruction or wreck. Both types of notices are intended to let boaters know it’s time to either manually update their existing paper chart or purchase an updated print-on-demand chart. Unfortunately, many recreational mariners fail to recognize the importance of these changes.