Historic Shipwrecks Spring 2015

Exam 1--Blue



6 @ 5 points



Short answer

4 @ 10 points




3 @ 10 points








No Authorized references.



Diagrams: These should clearly indicate understanding of the procedures and concepts involved, and should be well thought out with appropriate terms and details to support your answer.  You must answer four of the five questions.


Short Answer: The questions should be answered with several sentences (no more than a short paragraph). You must answer four of the five questions.


Budget your time.   Do not leave anything blank, and note that I am looking for an understanding of the important concepts and appropriate use of  terminology.


All work on this exam is individual.  You may not any materials (books, notes, computers, etc.), and you may not use IM, texting, talking, or any other means to communicate with other individuals.  If you are caught with an electronic device that is not turned off and inaccessible you will get a 0 on the exam.


Definitions/Terms:  Define 6 of the 11 terms.  You should have 2 sentences for each, and clearly define what the term means, and then explain why it is important in the context of searching for investigating shipwrecks.  Because you have a choice, I expect very high quality on your answers, so select terms on which you can shine.


·         Coriolis:

·         Crossover:

·         Curie temperature:

·         Fluyt:

·         Geoid:

·         Induced versus remnant magnetization:

·         Layback:

·         Lidar:

·         Mowing the lawn:

·         Slant range:

·         TWTT:


Insure that you only answered 6 definitions.

Short answer.  You must answer 4 of the 6 questions


Discuss the difference between latitude and longitude, in particular for ship navigation and interpreting the noon position fix in historic logbooks.





Discuss two ways that were used historically to compute depth in marine surveys, and explain the limitations that have caused them to be superseded.




Discuss two methods currently used to compute depth in marine surveys.  One of these had provided the best data in the Indian Ocean where MH370 crashed, and the other has been used to acquire newer data.  Explain the tradeoffs which influence which method is used to collect data.



Consider a magnetometer:

·         What does it measure?

·         What are you looking for with it?

·         Do you want to operate it close to the surface or close to the bottom?  Why?



We discussed two ways to introduce uncertainty in to modeling a ship’s drift: picking extreme likely end members, and adding random errors with Monte Carlo modeling.  How do these vary, and how can they help up plan a search?




What factors determine the strength of the return measured by a sidescan sonar, and what will produce the strongest return for each factor?





Consider two views of a shipwreck found in 125 m of water.


·         What technology was likely used, and why is that technology appropriate?

·         Note the x-coordinates are different in the two views (y is also different).  Why would we change the coordinate system, and does it make any difference in how we interpret the view?




The diagram above (omitted for copyright reasons) shows the search area for a sailboat and a lifeboat.  What forces operate on the two, and why do they respond differently?  How would you use this result in looking for a vessel like the BHR?




The map above shows the tracks of Spanish galleons ES-805, ES-1142 across the Pacific Ocean from the CLIWOC data base.  The wind vectors for August are shown, but they would not change substantially during other months.  This shows the routes among Peru (silver mines), China (fine porcelain purchased with the silver), the Philippines, and Mexico.  If you were looking for a lost galleon, would your search be different if you wanted silver or china?  Why?




How are these shipping lanes different from those we looked at in the Indian Ocean, and what causes the processes there to be different?  Why did pirates in the last 15 years have a different seasonal pattern compared to the sailing ships in the 18th century?