Red Sectors – The Lighthouse’s Silent Alarm

By Bob Trapani, Jr.

Fourteen Foot Banks' red sector
Photo by Bob Trapani, Jr.

The red sector in Fourteen
Foot Bank Lighthouse warns
mariners of dangerous
shoals in the vicinity

Prior to advancements in navigational technology during the 20th century, few scenarios caused more alarm in the pilothouse of a vessel transiting the Delaware Bay than to be found steering on a course that suddenly revealed a path marked by a lighthouse with the color red showing from its lantern. The tranquility afforded the voyage to that moment would suddenly be ushered aside and replaced by rising anxieties stemming from the sighting of one of the lighthouse’s signals of danger – the red sector.

During this heightened moment of concern, the captain or pilot knew all too well that if he didn’t take quick action to alter his course back into safer waters, which was designated by the sight of the color white showing from a light’s lantern along mid-channel, his fate would most certainly be decided by the deadly shoals or obstructions lurking just below the darkened waterline.

Red sector on Elbow of Cross Ledge Light
Photo by Bob Trapani, Jr.

Note the red sector on both
the main and emergency optics
of Elbow of Cross Ledge Light

Before the installation of red ruby glass panes in the lantern rooms of Delaware Bay lighthouses on December 1, 1884, all ship pilots were forced to avoid drifting from mid-channel waters in the bay on skill and experience alone. Though Delaware Bay lights flashed their lifesaving signals on a nightly basis prior to this of course, the white light beaming from the lantern room was more a marker of a dangerous area rather than a channel guide to safe transiting waters.

Like many waterways across our nation, the actual shipping channel of the Delaware Bay is an area where maneuverability is fairly restricted. Due to this fact, the Maritime Exchange for the Delaware River and Bay and the Pilots’ Association for the Bay and River Delaware began lobbying the U.S. Lighthouse Board in the late-1800s to implement enhancements to the region’s aids to navigation system. By the end of 1884, the Maritime Exchange was elated to announce, “An additional aid to navigation has been introduced by the Lighthouse Board, through the recommendation of Captain White, which has afforded great assistance to pilots and masters of vessels, namely the red sectors placed in principal lighthouses to cover the shoals on either side of the main ship channel – the established rule being to keep the light for which the vessel is being steered ‘white,’ noting that a change to ‘red’ indicated ‘danger.’”

Elbow of Cross Ledge Light
Photo by Bob Trapani, Jr.

(L to R) Senior Chief Dennis Dever records the
bearings of the red sector that QM1 Todd
Taylor is optaining with the True South Finder
at Elbow of Cross Ledge Light

This seemingly simplistic enhancement to safe navigation was originally comprised of red-colored glass panes situated overtop the clear glass panes of a light’s lantern (the ruby glass has been replaced today by red Lexan). Though uncomplicated in its appearance, maintaining the red sector’s effectiveness in the face of shifting shoals is anything but easy. In order for this to occur, servicing personnel must possess a precise understanding of the science of navigation to properly align each panel based on true compass bearings.

Today, the United States Coast Guard Aids to Navigation Team (ANT) Cape May, New Jersey, continues to uphold the traditional standards of excellence established by the U.S. Lighthouse Service in their role as modern day stewards of the Delaware Bay lights. This daunting responsibility includes the maintenance and proper alignment of the red sectors in each lighthouse, though the tool for accomplishing this important task might just as well hearken back to the bygone era of the lightkeeper.

Senior Chief Dever installs red Lexan
Photo by Bob Trapani, Jr.

Senior Chief Dennis Dever
installs red Lexan inside the
lantern room of Brandywine
Shoal Lighthouse

Despite the presence of computer-based technologies being integrated throughout the field of aids to navigation, a tool called a True South Finder continues to confound the notion that “good old-fashioned ingenuity” has no place in today’s digital electronic age. The simplicity of the True South Finder is made quite evident by examining its construction. Consisting of merely a three-arm protractor mounted on a block of wood, it begs the question of just how does the True South Finder work without any “bells and whistles.”

BM1 Chris Cartwright, Executive Petty Officer of ANT Cape May, answers this question, stating, “The way that the South Finder works is really very simple. You need to know the bearings from your position to a couple of objects that can easily be seen from where you are. Then you align those bearings on the South Finder to the objects.” BM1 Cartwright goes on to say, “This is done by setting the bearing, then sighting between the posts on the center and at either end of the protractor to the object. Once everything is aligned, you’re looking at a 360 degree ring, where 180 degrees is true south.”

QM1 Bishopp aligns red sector
Photo by Bob Trapani, Jr.

QM1 Earle Bishopp aligns the
red sector for Miah Maull Shoal
Lighthouse's emergency optic

Though modern day pilots guide massive vessels nearly 1000 feet in length up and down Delaware Bay with the assistance of Global Positioning Satellite (GPS) technology, lighthouses and their red sectors remain an important back-up system and a reassuring visual should electronic navigational equipment fail the pilot during his or her transit up the bay.

BM1 Cartwright understands the importance of this 119 year-old (as of 2003) practice of maintaining red sectors, noting, “The premise of the sectors is to provide the mariner with a visual reference of a danger area. If you see red you are tending towards shallow water or some other obstruction. If the sectors are not properly aligned it is a misleading signal that could either give a false sense of security or make a vessel tend to move away from safe water. In either case that could be a hazardous situation.”

Even without the presence of the vigilant lightkeeper, Delaware Bay lighthouses remain poised in the 21st century to continue their role of shining forth the unchanged historic silent alarm of the red sector to vessels that may stray from mid-channel during their transit to the tri-state ports of call in Delaware, Pennsylvania and New Jersey.

Harbor of Refuge Light's red sector
Photo by Herb Von Goerres

A view from inside the lantern room of
Harbor of Refuge Lighthouse at one
of the light's red sectors

BM1 Cartwright uses True South Finder
Photo by Bob Trapani, Jr.

BM1 Chris Cartwright views the bearings on
the True South Finder inside the lantern
of Brandywine Shoal Light

QM1 Taylor ascertains bearings for red sector
Photo by Bob Trapani, Jr.

QM1 Todd Taylor ascertains the bearings for
the red sector in Brandywine Shoal Lighthouse

Fourth Order Classical Lens
Photo by Bob Trapani, Jr.

A view of the fourth order classical lens
and Lexan panels that form the red sector
in Miah Maull Shoal Lighthouse

Created: March 2003