Sea Kayaking Safety and Rescue: Lighthouses and NOAA Charts

Today's topic: lighthouses and their value to small boat enthusiasts, not only as guideposts at night and in fog, but as daytime landmarks and tools for learning how to read nautical charts with a sharp eye.

A minor 20th-century American poet once wrote that as a symbol of loneliness, even a lighthouse has its limits. Yet it's isolation that many associate with lighthouses: lonely solitude, an overlook from some remote coast on wild weather and, until the mid-1900's in North America at least, a man and his family tending to a revolving beacon lit high in a tower perched on a bold headland, distant island or a offshore ledge.

For kayakers, lighthouses have value beyond the symbolic. The most obvious is a lighthouse's usefulness at night as a reassuring landmark. Paddling at night, as we feel our way down some bony length of coastline at night, we search for the lighthouse's distinctly coded flash pattern, find the lighthouse on the chart, and reassure ourselves that we are where we think we are, our companions use of gps notwithstaning.

As a practical matter, however, seeing that just a small handful kayakers are bold enough to paddle at night, and that most return to shore once dusk approaches or are leery of paddling in --- it's helpful to have a look at how lighthouses are depicted on a nautical chart and to consider how to use them, more realistically, as a useful landmarks in the daytime. Learning how to recognize a lighthouses on a chart teaches use how to read charts more carfeully, to pay closer attention to chart symbols and notations, and to better assess an area we plan to explore. Find a lighthouse symbol on a chart and you make note of where it lies relative to a headland, range for a long crossing, a crossroads that leads to a bay or cove, even a shipping channel to be on the lookout for.

Here's how a lighthouses is represented on a nautical chart: as a lavender exclamation point. Adjacent to that you'll see an alphanumeric code which describes the light's height, its flash pattern at night, the range of its light in darkness, whether the light station has a foghorn.

The code is useful and helpful for a whole host of reasons.

Let's take a look at a lighthouse on the southern coast of Massachusetts as an example: Gurnet Light, at Plymouth Bay, overlooking not only Plymouth but Duxbury and Cape Cod Bays. Perched high on a bluff that rises from a terminal glacial moraine that extends into southwestern Cape Cod Bay, Gurnet Light is a modest, stalwart-looking little building lighthouse. With an iron catwalk, clapboard siding, a foghorn and a solar panel array. The light's position has been shifted here and there a few times on the bluff by contractors, hired by the Coast Guard, as the bluff has eroded and changed shape in response to wind and wave erosion. The bluff was also used by the military: until the mid-1990's a submarine watchtower, remnant of US WW II coastal defense system, stood silent guard here as the lighthouse's grey and moldy, poorly-groomed cousin.

The scarp and bluff at Gurnet Point are periodically undermined by nor'east gales during the winter, sometimes collasping back a foot or two in one spilling, tumbling slide. Tall and wide and deeply-rooted as the bluff is, it's comprised entirerly of loose granular sand and glacial till. Bedded on an inherently unstable sand hill, erosion is Gurnet Light's lighthouse's constant nag. And because the light is fully automated, like virtually every lighthouse in the US, periodic relocation from one foundation to another is its sole amusement.

And although the nondescript keeper's house still stands, the light, powered by solar panels, turns itself on and off. The short, stubby light tower casts towards the nearby shoreline the steady gaze of electronic eye which measures dew point and the range of visibility, controlling the foghorn in reduced visibility.

So let's have a look at this lighthouse's usefulness to local sea kayakers and, by exrtapolation, to sea kayakers anywhere. The light's usefulness stems not so much from the fat wink of its light at night but, rather, from its position as a clearly visible daytime landmark that helps local paddlers who have read the light's related chart make fine and accurate assumptions about what lies to either side of the headland the light is perched on.

The related NOAA chart, for starters, shows us what the light's flash pattern, height and range are. The light lies 102 feet above sea level, has a flash pattern of three white flashes every 30 seconds, has a foghorn that bleats twice every 15 seconds, and is visible, at night, from the deck of a boat 20 miles away. We know all this by virtue of the light's simple code.

A close look at the chart, however, reveals not only that but so much more. We can see that, just northwest and southwest of the light, at its headland, lie two pocket beaches well protected from the weather. Which of those two pocket beaches the sea kayaker might choose for a landing, however, depends on looking at the chart once more. The beach to the northwest is open to nor'east winds and waves, making it a poor choice on days when heavy weather is coming from or due to come from that direction. Conversely, the beach to the southwest, while a fine choice in nor'east winds, is fully exposed to the lively if not sometimes overwhelming thermal southwest winds that characterize this shoreline during the late spring and early fall.

In this way, reading the land and seascape proximal to this unassuming little lighthouse gives us plenty of insights come time to plan a trip here. If weather comes in heavy from the southwest, we should look for the light and duck in on the its beach on the northwest shore. It weather is heavy from the northeast,, on the other hand, we should take cover on the beach under the light's southwest shoulder.

Latitude 42° 0" 13' Longitude -70° 36" 1'
Height Above Water 102 feet
Light Characteristics Three white flashes every 30 seconds with a red sector for Mary Ann Rocks.

Taking a careful look at the lighthouse as it's represented on the chart helps us make all these assumptions and plans before we launch the boats. And we know all this not only because the lighthouse was placed there to mark this headland, but because reading the chart show us that, on this narrow section of coast, the bluff that holds the lighthouse falls away to flat and low, boulder-edged beaches on its two corners. Between the two beaches the bluff rises abruptly, acting as a wind and weather barrier. The charts shows us the distinct change from high bluff to pocket beaches: the bluff is drawn differently that the nearly level pocket beaches with with their slight rise to the dunes and foreshore.

Safe haven, and easy to find in daylight, given the lighthouse's height and prominence. Safe haven too, though a little less easy to find, at night also, so long as we know to scan the shoreline for the light's distinct flash pattern of three white flashes every thirty seconds. Thus a light meant to provide guidance in fog and darkness becomes a landmark we use in the day to find daytime protection from heavy weather, or simply two nice places to land. The pocket beaches which lie to either side of the bluff which lift the light can be, if not lifesavers, then simply trip enhancers.

Well that's it for today's installment of Sea Kayaking Dot Net's Fence Post Navigation Series. I'm Adam Bolonsky, on the web at paddlingtravelers.blogspot.com. Thanks for stopping by. And until next time, see ya round.