1. Wind and Current Junior Navigation Chapter 12

2. 2 Learning Objectives Distinguish between leeway and current Distinguish between leeway and current Know the meaning of: Know the meaning of: DR track; Intended track; Speed of advance; Course & speed over ground; Course & speed made good; Drift angle DR track; Intended track; Speed of advance; Course & speed over ground; Course & speed made good; Drift angle Determine course to steer, allowing for current/leeway Determine course to steer, allowing for current/leeway Determine set and drift of current Determine set and drift of current Determine leeway Determine leeway Understand elements of estimated reckoning Understand elements of estimated reckoning

3. 3 Current vs. Leeway Horizontal motion of water Horizontal motion of water Current vector: Current vector: both direction (set) and speed (drift) both direction (set) and speed (drift) Sideways movement caused by wind Sideways movement caused by wind Magnitude of leeway - varies with: Magnitude of leeway - varies with: Speed & relative direction of wind Speed & relative direction of wind Type of vessel Type of vessel Speed of vessel Speed of vessel “Current” - net offset (DR-to-fix) caused by current, leeway, wave action, and/or steering error “Current” - net offset (DR-to-fix) caused by current, leeway, wave action, and/or steering error

4. 4 Vessel Motion Through Water Intended Course (C) Course (C) Direction boat is or is to be steered through the water Direction boat is or is to be steered through the water Speed (S) Speed (S) Rate of motion of boat through water in the direction it is or is intended to be steered, assuming no current or leeway effects Rate of motion of boat through water in the direction it is or is intended to be steered, assuming no current or leeway effects DR Track DR Track Path of boat through water projected from a known position (fix), based solely on course & speed Path of boat through water projected from a known position (fix), based solely on course & speedAccomplished Course (C) Course (C) Direction a vessel was steered through the water Speed (S) Speed (S) Rate of motion of boat through water in the direction it was steered, assuming no current or leeway effects DR Track DR Track Path of boat through water projected from last known position (fix), based solely on course & speed

5. 5 Accomplished Course Over Ground (COG) Course Over Ground (COG) Actual path over bottom Actual path over bottom Course Made Good (CMG) Course Made Good (CMG) Net direction over bottom Net direction over bottom Speed Over Ground (SOG) Speed Over Ground (SOG) Actual speed over bottom Actual speed over bottom Speed Made Good (SMG) Speed Made Good (SMG) Average speed over bottom Average speed over bottom Intended Intended Track (TR) Intended Track (TR) Expected path over bottom, taking current & leeway into account Expected path over bottom, taking current & leeway into account Speed of Advance (SOA) Speed of Advance (SOA) Expected speed along intended track, taking current & leeway into account Expected speed along intended track, taking current & leeway into account Vessel Motion Over Bottom

6. 6 Accomplished Motion 1800 GPS 1900 Wind and/or Current CSCS 2030 GPS SET DFT CMG SMG 2000 2030 (Net offset) TR SOA COG SOG COG SOG COG SOG COG SOG COG SOG

7. Allowing for Current TR= 075° S = 8.0 kn Set = 100° Drift= 3.8 knots DR Course 0 1 3 2 4 5 6 7 8 9 10 11 12 SET 100 DFT 3.8 8.0nm S 8.0 C 063 SOA 11.3 TR 075 S 8.0 C 063 (Expected path over bottom) (Expected speed over bottom) (Direction boat is steered) (Speed of boat)

8. Allowing for Current & Leeway TR= 075° S = 8.0 kn Set = 100° Drift= 3.8 knots 20kn from 315º 5º leeway 0 1 3 2 4 5 6 7 8 9 10 Course to steer 11 12 SET 100 DFT 3.8 S 8.0 C 063 SOA 11.3 S 8.0 C 063 1000 GPS TR 075 1100 C 058 5º drift angle On which line would you plot your 1100DR position? 20 kts 1100 GPS Where should your 1100GPS position be? drift angle correction

9. 9 Puerto Rico to Cristobal, Panama Puerto Rico to Cristobal, Panama Start: L 18º 00´N, Lo 67º 51´W Start: L 18º 00´N, Lo 67º 51´W Leave: 0800 1 July Leave: 0800 1 July Boat: 38-foot cutter, should average 6.0 kn on this generally downwind course Boat: 38-foot cutter, should average 6.0 kn on this generally downwind course The captain wants to know: The captain wants to know: What conditions to expect? What conditions to expect? How long the trip will take? How long the trip will take? ETA? ETA? What course to steer from the departure point? What course to steer from the departure point? Allowing for Current & Leeway

10. 10 What Conditions to Expect? 12ft seas 10% Force 4 or 5 Winds out of NE or E Current set 270º at 0.8-1.0kn

11. 11 How long with it take? T = D / S T = 875 / 6 T = 145.8 hrs T = 6 days 1.8 hrs

12. 12 What is the ETA? ZT 1 Jul 0800 ZD +4 UT 1 Jul 1200 Travel +6 2 UT 7 Jul 1400 ZD (rev) –5 ZT 7 Jul 0900

13. 13 Course to Steer?

14. 14 C 229 S 6.0 Set 270 Dft 0.9 TR 234 SOA 6.7 Course to Steer? S 6.0 (expected path over bottom) (boat speed/course through water) (boat speed over bottom) (course to steer) (current affect) T = D / S T = 875 / 6.7 T = 130.6 hrs T = 5 days 10.6 hrs ETA 6 Jul 1800 T = 6 days 1.8 hrs ETA 7 Jul 0900 Cristobal Puerto Rico C 229

15. 15 Underway Navigator’s tasks include: Navigator’s tasks include: log boat’s progress (chart & deck log) log boat’s progress (chart & deck log) Assess current, leeway, and other factors affecting boat’s course Assess current, leeway, and other factors affecting boat’s course Periodically adjust steering course to stay on desired track Periodically adjust steering course to stay on desired track

16. 16 When Fixes & DRs Differ Navigator needs to know origin of difference Navigator needs to know origin of difference Consider what the reason might be Consider what the reason might be Review all data and ask questions: Review all data and ask questions: Have you plotted correctly? Have you plotted correctly? Does pilot chart show a change in current? Does pilot chart show a change in current? Does observed current match expected current? Does observed current match expected current? Has the wind speed/direction changed? Has the wind speed/direction changed? Have sea conditions/boat performance changed? Have sea conditions/boat performance changed? Is there an error in calculating DR? Is there an error in calculating DR?

17. 17 Estimated Reckoning In absence of fixes, rely on DR & knowledge of boat to determine position In absence of fixes, rely on DR & knowledge of boat to determine position Consult charts and pubs for average currents Consult charts and pubs for average currents Consider weather Consider weather Considering all factors, arrive at an estimated position (EP) Considering all factors, arrive at an estimated position (EP) Process – called Estimated Reckoning Process – called Estimated Reckoning Takes experience to do correctly Takes experience to do correctly The longer without a fix, the more important to know the factors that affect your position The longer without a fix, the more important to know the factors that affect your position Navigator’s Job: constant process of observation, analysis, and cross-checking position!

18. 18 Wind and Current End of Junior Navigation Chapter 12 Turn in your Sight Folders

19. 17ºW 14ºW 15ºW 16ºW Plot initial and destination coordinates on the July Pilot Chart WP1 WP2 17ºW 14ºW

20. 17ºW 14ºW 15ºW 16ºW 1a. What is the true course for the rhumb line between your initial and destination coordinates? WP2 WP1 C 151

21. 17ºW 14ºW 15ºW 16ºW 1b. What is the expected magnetic variation along this course? WP2 C 151 WP1

22. 17ºW 14ºW 15ºW 16ºW 1c. What would be the planned magnetic course along this rhumb line course? WP2 C 151 T = 151º V = +15ºW M = 166º WP1

23. 17ºW 14ºW 15ºW 16ºW 1d. What is the distance of this course? WP2 C 151 9º 10’ 9 x 60 = 540 540 + 10 = 550nm D 550 WP1

24. 17ºW 14ºW 15ºW 16ºW 1e. Assume an average SMG of 6.0kt, what will be your elapsed time to complete this voyage? WP2 C 151 D 550 T = D / S T = 550 / 6.0 T = 91.7 hrs WP1

25. 17ºW 14ºW 15ºW 16ºW 1f. (Optional) Using GPS determine true course, distance and elapsed time for this voyage. WP2 C 151 D 550 WP1 Bearing WP1 to WP2 = 151º Distance 548nm Elapsed time 91.3 hrs

26. 17ºW 14ºW 15ºW 16ºW 1g. At 180nm from WP1, what will be: wind direction; wind force; current set/drift? WP2 C 151 D 550 Direction = SW Force 4 Set 058º-062º Drift 1.5/1.0kn WP1 X

27. 17ºW 14ºW 15ºW 16ºW 1h. What are the names of major shipping lanes that cross your course and distance from WP1? WP2 C 151 D 550 Cape Hatteras to Virgin Rock – 200nm Cape Hatteras to Gibraltar – 300nm Bimini Island to Bishop Rock – 460nm WP1

28. 17ºW 14ºW 15ºW 16ºW 1h. What are the coordinates of where your route intersects Cape Hatteras to Virgin Rocks? WP2 C 151 D 550 L 37º 50’ N, Lo 68º 20’ W WP1

29. 17ºW 14ºW 15ºW 16ºW WP1 1h. What is the rhumb line course at this intersection? WP2 C 151 D 550 058º

30. 17ºW 14ºW 15ºW 16ºW WP2 C 151 D 550 1h. What are the coordinates of where your route intersects Cape Hatteras to Gibraltar? L 36º 40’ N, Lo 67º 20’ W WP1

31. 17ºW 14ºW 15ºW 16ºW 1h. What is the rhumb line course at this intersection? WP2 C 151 D 550 071º WP1

32. 3. Sailing Directions - Planning Guide Public Holiday Act, 1947 All Government Offices, including Post Offices, are closed on every public holiday. The following Monday will be observed as a public holiday when a public holiday with a fixed date falls on a Saturday or Sunday. Store, shops, & businesses, except those with a holiday trading license - able and willing to pay their staff double overtime, will be closed. All Restaurants are closed, except restaurants owned by hotels which may remain open. Buses and ferries are on a much-reduced schedule and many taxis do not operate.

33. 3. Sailing Directions – Enroute (Pub 147)

34. Currents become matters of concern only within confined channels leading through reefs… flood currents set directly onto reefs. Saint George’s Harbor has been reported to be radar conspicuous. An inbound vessel has right- of-way, and should fly her national colors while navigating channels to claim priority. 3. Sailing Directions – Enroute (Pub 147)

35. Sea approaches are generally free of dangers, except for two off-lying seamounts to the SW and the sunken dangers of Bermuda Great Reef. The attention of all mariners is drawn to the dangers and hazard of close approach to the reefs which surround Bermuda, especially to the N and NE of the islands. They extend in places to a distance of 12 miles from the visible land and are virtually unmarked by navigational aids at their extremities. Reef information 3. Sailing Directions – Enroute (Pub 147)

36. World Port Index 9940 World Port Index 9950 3. Sailing Directions – Enroute (Pub 147)

37. Hamilton Harbor is not considered to be a good hurricane anchorage. The holding ground is good, but space is limited in such circumstances. Great Sound is considered preferable. World Port Index 9960 3. Sailing Directions – Enroute (Pub 147) Caution – Numerous small craft, which may not be carrying anchor lights, may be found in Hamilton Harbor, clear of the main fairway.

38. 8. Entry requirements - Customs What do you do upon arrival?

39. What can you bring into Bermuda? 8. Entry requirements - Customs

40. What are the duties? 8. Entry requirements - Customs

41. How much cash can you have onboard? 8. Entry requirements - Customs

42. What about food? 8. Entry requirements - Customs

43. What about food? 8. Entry requirements - Customs

44. What about pets? 8. Entry requirements - Customs

45. How about your medication? 8. Entry requirements - Customs

46. Other items? 8. Entry requirements - Customs