NOAA Teacher at Sea
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012
Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: February 15, 2012
Weather Data from the Bridge
Position: Windspeed: 15 knots
Wind Direction: South/Southeast
Air Temperature: 23.9 deg C/75 deg F
Water Temperature: 24.5 deg C/76 deg F
Atm Pressure: 1016.23 mb
Water Depth: 4625 meters/15,174 feet
Cloud Cover: less than 20%
Cloud Type: Cumulus
Crew and scientists are reporting for duty and everyone is to be onboard by sunset for a scheduled departure tomorrow morning. There are many boxes of equipment to unload and sampling devices to assemble, so everyone is busy, even during meal times.
Tall ships had miles of rope and lines for handling enormous amounts of sail.
The Brown is also carrying miles of line and cable too, but not for sailing. This is coiled neatly on reels and will be used to anchor moorings of monitoring equipment that will record water temperatures and salinities for an entire year until they are recovered on the next cruise. These moorings are anchored with ship recycled chain and old railroad wheels and their long lines of sensors rising to the surface from 5,000 meters form the electronic “picket fence” spaced between Florida and Africa across the 26.5 degree North Latitude line we are sailing.
On our last night ashore we went downtown to enjoy dinner at one of the many nice restaurants in the historic district. It was a good time to update each other on different projects and make any last minute purchases. Everyone is anxious to get started. As captains like to say:
“Ships and sailors rot at port.”
Day 3 We are leaving the dock on schedule and heading down river.
Old sailors’ superstitions say that a small bird or bee landing on the deck of a departing vessel foretells good luck on a voyage, and a tangled anchor line forecasts bad luck. Glancing around, I observe our noisy grackles preparing to depart neighboring ships at dock – so I hope they qualify as small birds. And huddled out of the wind on deck is a crane-fly – not a bee, but a harmless bug that looks like a giant mosquito. Perhaps no guarantee of good luck, but since all our lines and chain are neatly stowed, I am confident that an old “salt” – seeing how ship-shape the Brown is – would concur that we shouldn’t unnecessarily envision any bad luck on our cruise.
Sailing down river we receive a great treat and are guided to the sea by small groups of dolphins surfing underwater in our bow wave. These are Tursiops – the bottle-nosed, the most common and well-known members of the dolphin family Delphinidae. Tursiops is Latin for “dolphin-like.” Their comradeship is another reassuring sign of good luck to suspicious sailors. It is a remarkable spectacle and entertainment to everyone, even the veteran crew members, who, like the ancient mariners, have reported it many times. Although they seem to be taking turns at the lead, one dolphin that keeps resurfacing has a small cross-shaped scar on the port side (Left) of the blowhole; proving that at least one member of the pod has kept pace with us for the entire time.
Curiously, they know to abandon us near the river mouth to join other “bow riders” that have caught the wave of a freighter that is entering the river and heading upstream. Noteworthy is the bulbous bow protruding in front of the freighter. Reminiscent of the bottle nose of a dolphin, the bulb modifies the way the water flows around the ship’s hull, reducing drag – which increases speed, range, fuel efficiency and stability – things dolphins were rewarded with through evolution. And what a show the dolphins make riding the steeper bow wave! Actually launching out of the vertical face of it like surfers.
Passing historic Ft. Sumter we receive an impromptu lecture by some of the crew on Charleston’s rich history from the days of Blackbeard the pirate, up through the Civil War. There is an interesting mix of people on board, from several countries and with extraordinary backgrounds. There is also a great assortment of vessels using the bay – freighters, tankers, tugs, patrol boats, cranes, sailboats and a huge bright cruise ship. I am reminded of Walt Whitman’s Song for All Seas, All Ships:
Of ships sailing the seas, each with its special flag or ship-signal,
Of unnamed heroes in the ships – of waves spreading and spreading
As far as the eye can reach,
Of dashing spray, and the winds piping and blowing,
And out of these a chant for the sailors of all nations…
I note a transition here from the river to bay ecosystems reflected in the birdlife observed. Grebes and mergansers are replaced by pelicans and gulls.
The bay mouth is protected from wave action by low rip-rap jetties, and outside of them in a more oceanic environment are loons, scoters, and our first real seabirds – northern gannets. Loons spend the summer and nest on pristine northern lakes like those in New Hampshire (Reminding me of the movie On Golden Pond) but migrate out to saltwater to winter in ice-free coastal areas.
Scoters (Melanitta) are stocky, dark sea ducks that winter over hard bottoms like the harbor entrance, where they can dive down and scrape mussels and other invertebrates from the rocks and gravel.
Gannets are cousins of the pelicans but much more streamlined. They too dive for food but from much greater heights, sometimes over 100’. They also plunge below the surface like javelins to snare fishes. They are wide-ranging visitors along the East and Gulf coasts, wintering at sea, and returning to isolated cliff nesting colonies known as a “gannetry” in Maritime Canada
The ship was cheered, the harbor cleared,
Merrily did we drop,
Below the kirk, below the hill,
Below the lighthouse top.
Sullivan Island lighthouse
Latitude: 32.75794 Longitude: -79.84326
The odd triangular shaped tower of Sullivan Island lighthouse originally had installed the second brightest light in the Western Hemisphere. (Said to be so powerful that keepers needed to wear asbestos welding gear when servicing the light)
At 163 feet, its unusual flash pattern is tricky to catch on camera, but it is our last visual link to the mainland, and it will be the only land feature we will see until we are off the lighthouse at Abaco, Bahamas, after ten days at sea. A lighthouse keeper at the lens room, watching us sail away, could calculate at what distance (in miles) we will disappear over the horizon with a simple navigator’s formula:
The square root of 1.5 times your Elevation above se level.
Try it out: √1.5E’ = _____ Miles
√1.5 x 163′ = _____ Miles to the horizon
(Images on the Ron Brown by Dave Grant)