Self Assessment 12
§ 43 – 45
For Q. 210, use SRT for Marine Navigation N.P. 401 Vol. 4.
205. What type of small craft do you consider most suitable for long-distance ocean cruising.
206. Give reasons for your answer, and also state what items of equipment are particularly important for an ocean passage in comparison with those for ordinary coastal or short-distance cruising,
207. What vitamin-deficiency is most likely on a long passage in a small craft and what could this lead to?
208. What steps would you take to protect your crew from this eventuality both directly and in the provisioning of the vessel and daily diet at sea? Describe the ocean passage planning data which is available, and how should this be used to select the best route for a small craft?
209. What is:
a. a Rhumb line?
b. a loxodromic curve?
c. the Sailings?
210. What are the advantages and disadvantages of a Rhumb line track?
211. With the aid of diagrams describe how a Great Circle track can be plotted on a Mercator chart and how it would be followed by a vessel at sea.
212. What is a Composite Great Circle Track, and how is one plotted and followed by a vessel at sea?
213. Discuss the practical use of Great Circle sailing in a small sail including the tactical value of windward Great Circle sailing.
214. Calculate the Great Circle distance and final course from the NE Providence Channel (Bahamas Is.) in Lat. 26º 15.0 N., Long. 077º 10.0 W. to Bordeaux in Lat. 40º 00.0 N., Long. 002º 10.0 W.
∴ Distance 3681.1 Nautical Miles. Course 279º – 180º = 099º (T).
a. Calculate the distance along-the composite Great Circle track between: Wellington (New Zealand) in Lat 41º 35.0 S., Long. 175º 20.0 E. and Cape Horn in Lat. 56º 03.0 S. Long. 067º 15.0 W. with the limiting parallel of Lat. 58º S and state the positions of the two points of tangency to the limiting parallel.
d.long between departure point & Point of Tangency (z) = 56.3 + Long. of Wellington 175º 20’ E = 175º 20’ E
d.long. between destination & Point of Tangency = z = 21.9º = 21.54’ to ADD to Long. of Cape Horn 67º 15’ W
215. What particular precautions must be observed when navigating in the South Pacific Ocean and why?