Message in a Bottle

Home , Message in a bottle

CRW1217_GRN_Message.indd 38 38 november/december 2017 cruisingworld.com making a timely escape before before escape making atimely Gulf ofMiami, Streamnorth of Floridaandexited the Mexico, navigated theStraits Loop CurrentintheGulf of beenentrainedinthe clearly Lauderdale. The bottlehad program onabeachnearFort inascience while participating group thatfoundthebottle anelementary-school from enough to receive anice letter months later, lucky hewas west ofKey West. Several islandcluster a small 60miles Florida, to theDry Tortugas, St.Petersburg,sailing from program research on acollege ﬁ inabottlewhile rst message beachcombing. ﬁwill while nd themessage upupon,andwho wash will dream ofthedistantshoreit inabottle,one can a message in theactualoutcome. With rarely the dreamingandonly lottery, inthatthevalueis bottle issimilarto playingthe sailors. Tossing ina amessage formanyoffof passage shore isatraditionalrite overboard ing theendandthrowingit W My his husband,Eric,sent Why couldn’t we track messages? our People track boats, dogs, phones even and the glass bottle,cork-glass itinto a inserting riting amessage, GREEN

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single one of these messages messages single oneofthese in New Zealand.Sofar, nota ing nearSeattleandending originat-a two-year voyage Rouser thePaciﬁcrossed c Ocean on corkedsafely we inbottles,as messages, deployed several Atlantic Ocean. acrossthe the longpassage Several yearsSeveral later, we BY ERIC AND ANGELA SIEGEL Green Wakes , our Tartan 37, during location oftheir keys these days. in a we crossed the we crossed Atlantic Ocean. inbottles as messages sending children to theexperience of introduced ourthreeyoung be found. and wheretheymightoneday tive pathsthroughtheseas dreaming abouttheirrespec- hasn’t prevented usfrom beenrecovered. Butthathas Most recently, we have BOTTLE on thewayto Barbados. days outfrom Cape Verde to deploy Drifter Eﬁve prepareAngela andEliana Islands andtheCape Verde Spain, Portugal, theCanary in theCaribbean, withcalls nated inScotland andended Westerly 49, onourtrusty Our passage, Laridae , origi- 9/25/17 5:06 PM ERIC SIEGEL GREEN WAKES

islands. This time, however, Writing the messages in the positions: 15°N, 30°W (Drifter order to jump overboard to the messages that our children bottles was a fun group activ- A); 14°N, 32.5°W (Drifter D); clean the speedo, or should we launched were much diff er- ity. Prior to leaving Scotland, 13.5°N, 35°W (Drifter E). The continue to enjoy the fi rst few ent. The innovative concept we had a bon voyage party drifters were deployed in age hours of our grand departure, began when one of our chil- with our children where their order of our children, but it sailing in close company with dren naively asked us why we friends wrote messages for helps that this is also (acci- the 30 other boats around us in didn’t know where our previous inclusion in the bottles. Later, dentally) in alphabetical order. the rally, and live for the next bottles were located. As with having joined Jimmy Cornell’s When we set out the fi rst two weeks without the knot-log most things, each new genera- Barbados 50 rally to cross buoy, the true-wind speed was data? After our recent show- tion has a more contemporary the Atlantic, we invited all of about 25 to 30 knots from the ers and the knowledge that few take on things, even age-old the kids and adults to write northeast to east-northeast. showers were in store over the traditions such as this. Why messages and draw pictures The wind slowly diminished to next few weeks, the fresh, clean couldn’t we track our messages? to include in the bottles. The about 25 knots for the second feeling won out over a salty People track boats, dogs, three bottles were corked drifter, and to around 20 knots swim. We decided to continue phones and even the location on the dock in Mindelo, an when the third drifter on toward Barbados, sailing of their keys these days. island in Cape Verde, and tied was launched. within sight of our fellow rally Our messages keep to securely to the three drifting Trained as a physical boats, but without a work- tradition in some ways, but buoys. The drifters were given oceanographer, Eric was ing log to be able to estimate wildly deviate in others. We letter identifi cations after very excited to sail across the ocean currents. Fortunately, the decided to attach our stan- our kids’ names: Drifter A for Atlantic Ocean and compare drifting GPS buoys were able dard message-carrying bottles to satiate our interest in the to modern drifting buoys that ocean currents, and following

transmit their position to a their course across the Atlantic satellite. Now, we all get to Ocean has been fascinating for track their meandering routes the entire family. across the ocean and, with the understanding of surface winds Tracking the Drifter Buoys and ocean currents, make When the drifters were educated guesses of where they deployed, the trade winds will ultimately go. were blowing from the typi-

cal direction of northeast to cruisingworld.com Drifter Buoy Technology east-northeast at a speed of Our friends at Marine about 25 knots. For the ﬁ rst 39

Instruments, an innovative fi ve days (and 100 miles of buoy technology company in Spain, drift), the buoys followed our donated the drifting buoys for path so closely that we received the project. The MSi drifter an email from Eric’s father buoys (marineinstruments.es/ asking if we had tied them to tuna-fi shing/buoys-msi-blue) our transom and were towing contain a GPS for positioning, them along. Even though the an Iridium modem for satellite drifters were directly follow- transmission of the position ing our path, the buoys were and a small solar panel to keep not drifting exactly down- the batteries charged. The drift- The Siegels set up a website to track their bottled messages wind. We had been sailing on ers transmit their GPS position (orange, red and yellow lines), and were amazed to see how a starboard tack, with a wind every 12 hours via the Iridium closely the drifters followed their own path (blue line). angle of about 140 degrees. modem. The drifters do not Therefore, the buoys were november/december 2017 have a sea drogue and have Anneka, Drifter D for Dorian our knot-log speed (speed following an angle about 40 very little exposed windage. and Drifter E for Eliana. Each through the water) with our As a result, they drift primarily of our three children deco- GPS speed (speed over ground) with the ocean surface currents rated their bottle and their to try to estimate the ocean- CURRENT found in the top few feet of the assigned drifting buoy and current speed. However, CONVENTION water. This surface layer is added the words “Read Me” in within moments of depart- The standard convention for the same layer that aff ects sail- large letters. ing the dock, we learned that describing winds is “from.” boats with typical drafts from Mindelo’s harbor inspires a An easterly wind is blowing 4 to 8 feet. Current lore of the Drifter Buoy Deployment lot of critters to make them- from the east. The conven- tropical Atlantic Ocean is that We launched the message-fi lled selves at home on the hull, and tion for describing currents is “toward.” A northward the buoys should drift mostly bottles and drifters on days our knot log was fouled with current is moving toward downwind, at an approxi- three, four and fi ve (November new growth. While surfi ng the north. mate speed of half a knot. Our 11-13, 2016) after departing down waves with 35-knot gusts, friends at Nortek Data Services Cape Verde on our 2,100-mile funneling through São Vicente have graciously volunteered to passage to Barbados. The drift- Canal between the islands of degrees to the right (clockwise) host a webpage that plots our ers were deployed with an equal São Vicente and Santo Antão, of the wind direction. This is sailing route and the position spacing of 2.5 degrees of longi- serious soul-searching had to be consistent with how surface and path for the three messages tude (approximately 145 miles done. Should we divert course currents should be oriented tied to the drifting buoys. apart at this latitude) at the to a protected anchorage in with respect to the prevailing

CRW1217_GRN_Message.indd 39 9/25/17 5:06 PM of their intended westward TRACK THE DRIFTERS direction due to the Coriolis The position of the three drifting buoys is tracked Scotia, Canada. The SVP buoy uses a large drogue force. The north-northwest in real-time and can be found by clicking on the to control its drift. The sea-anchor type is known drift persisted for another map link on the bottom of the webpage as a “holey sock drogue.” It essentially looks likes 10 days before the typical laridae.ca/2016/11/29/drifter. The blue line shows its name, and is designed to be centered about 50 east-northeast trade winds the path that Laridae sailed between Falmouth in feet below the sea surface. The holey sock drogue kicked back in and carried the the U.K. and the Virgin Islands. Drifter A is orange, reduces wind drift and enables the drifting buoy to drifters westward again. Drifter D is red and Drifter E is yellow. follow the average subsurface currents in the top As the drifters approached layer of the ocean. These currents typically move the Caribbean island chain, The Drogued Drifter: A diff erent type of drifting more slowly than the wind-driven surface currents. we expected that they would buoy (shown with a green line on the map) was The green path of this drifter shows the slower but be pushed substantially north- deployed on the passage between the Canary much more intricate path of the average currents. ward. Before crossing the Islands and the Cape Verde islands on October 16, These currents are controlled both by the prevailing Atlantic, we had been warned 2016, at position 19° 04’ N, 22° 37’ W. This buoy, trade winds and the local gravitational tides. When to make sure we had achieved called a Surface Velocity Program buoy, was gen- the green path is viewed in detail, the clockwise- enough southing before we erously donated by our friends at MetOcean rotating tidal currents are evident, particularly reached Barbados, because Telematics (metocean.com), headquartered in Nova during times when the trade winds have relaxed. there could be a strong northwest current that would be diffi cult to ﬁ ght against if we wind direction. Ekman spiral is a root of weakened wind zone, but needed to get farther south to The rotation of Earth causes nontidal sea-level variations many participants in the 2016 clear the shoals on the south

the Coriolis force to direct the along the coasts, as well as the Atlantic Rally for Cruisers side of Barbados. However, near-surface currents about 45 large ocean gyres in the open encountered a huge wind hole there was little evidence of any degrees to the right (clockwise) oceans and resulting currents, in the middle of the Atlantic substantial northwest compo- of the wind direction in the such as the Gulf Stream. Ocean. During this time of nent of current until the Northern Hemisphere. The In late November, about 10 decreased wind forcing, the drifters reached the longitude clockwise rotation of currents days after our departure from drifters started moving in a of Guyana (approximately 150 continues with increasing Cape Verde, the trade winds more northward direction miles east of Barbados). depth to form a spiral pattern dropped substantially. Luckily, toward the north-northwest, Amazingly, Drifter E passed

cruisingworld.com called the Ekman spiral. The we were already west of the again turning to the right within 5 miles of the south

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CRW1217_GRN_Message.indd 40 9/25/17 5:17 PM GREEN WAKES

coast of Barbados, which winds, sailors can expect passing between Jamaica and was precisely the path that stronger surface currents that ONLINE Honduras, before getting we navigated! It is highly are oriented about 45 degrees RESOURCES caught in the headwaters of unlikely that we could ever to the right of the prevail- the Loop Current that orig- There are many good online again release a drifter 2,000 ing trade-wind direction in resources for viewing observed inates between Cuba and miles upwind and expect it the Northern Hemisphere. and predicted ocean surface the Yucatan Peninsula and to arrive within 5 miles of However, if the trade winds currents. OSCAR (Ocean entering the Gulf of Mexico. our destination. Drifter D relax, it is important to note Surface Current Analysis There are a number of great entered the Caribbean Sea by that the surface currents can Real-time) is a NASA-funded online resources that show passing between Dominica weaken, change direction or project to assimilate satellite measured and predicted ocean and Îles des Saintes. This is even reverse against you for a measurements of ocean height surface currents around the and ocean temperature with a route heavily traveled by short period of time. ocean wind data in order to globe. We encourage you to cruising sailboats, and it is fun model and predict the ocean track our drifting messages in to wonder how many fellow Where Will the Messages surface currents. A great inter- bottles, research the prevail- sailors passed right by the Go Next? active viewer for the OSCAR ing trade winds and surface small drifter without notic- All three drifters were ocean-current data can be currents, and place your bets ing it. Drifter A, released ﬁ rst, deployed within about found at earth.nullschool.net. on where the bottles will end To view the ocean-current was most recently reported 300 miles of one another. data, make sure to click up. We all look forward to to be passing north of the However, over the past six on “Settings” to enable learning of the lucky but unsus- Caribbean island chain. Over months, and 2,200 miles later, “Mode = Ocean” and pecting beachcombers who the past six months, the two have taken a similar path “Animate = Currents.” ﬁ nd these unique creations. drifters have traveled approx- into the Caribbean Sea, and

imately 2,200 miles. After all one has drifted north of the In 2002-2003, Eric, a physical of that distance, Drifter D Caribbean. Drifter A, having it will likely be entrained in oceanographer, and Angela, and Drifter E were only about been carried north of the the Gulf Stream and join the a mathematician, crossed the 250 miles apart. Caribbean, will likely slowly ocean highway back across the Paciﬁ c, fr om Seattle to New In summary, the drifters continue northwestward Atlantic toward Ireland. Zealand. Nearly 15 years and moved with the surface toward the Bahamas, carried Drifters D and E are three children later, the family currents at an average speed by the prevailing southeast in the Caribbean Sea and crossed the Atlantic fr om Scotland of approximately half a knot. trade winds in the spring and will likely continue to drift to the Caribbean aboard Laridae, In times of increased trade summer season. Eventually, slowly westward, possibly their 1995 Westerly 49. cruisingworld.com

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CRW1217_GRN_Message.indd 41 9/25/17 4:55 PM