Historic Shipwrecks

Spring 2017

Blue Science Exam


Definitions (7/9)

7 @ 4 points



Short answer (3/4)

3 @ 8 points



Diagrams (4/5)

4 @ 12 points








No Authorized references.


You have choices.  Use them wisely, and insure you understand the questions you choose to answer.


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 7 of these 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 and investigating shipwrecks.


1.      Differentiate cross track and along track:

2.      Crossover:

3.      Relate 1500 m/s to TWTT:

4.      Differentiate Layback and Leeway

5.      Geoid

6.      Multi beam echosounder:

7.      Curie temperature

8.      2.5D versus 3D

9.      Noon fix or sighting:

Insure that you only answered 7 definitions



Short answer.  You must answer 3 of the 4 questions

How does singlebeam bathymetry work?



How can we use gravity to measure bathymetry, how much detail can it reveal, and why is it frequently the best data we have in the deep ocean?




What does a magnetometer measure, and what can we locate with it?  What difference does sensor height have on the final results?  Would you get better results using an aircraft or towing it behind a ship—give one reason why you might prefer each.




Relate the Curie temperature to permanent (or remnant magnetization) and induced magnetization, and which would be more likely to be useful to looking for iron cannon.





Insure that you answered 3 of the 4 questions in this section

Answer 4 of the 5 diagrams.



1. What kind of instrument collected this data?  How is it employed, and how is the image collected?


Can you tell which way the ship moved?  Why or why not?


What do the colors represent, and what controls the color you see?






2. Map A shows the route of ship UK-1534 in the fall of 1802, with two voyages 1 and 2 in the northwestern Indian Ocean.  One voyage is during September, and the other in latest November and early December.  Maps B and C shows climatological wind vectors in September and December. 

·       What causes the dramatic change in the winds between these two months?

·       Which map, B or C, is for September and which is for December, and how can you tell?

·       Which route, 1 or 2, is for September and which is for December, and how can you tell?

·       (this is part of figure 2)  Maps D and E show modern piracy in the same part of the Indian Ocean, during the months of August and December.  Can you identify which month is which?  Do the pirates respond differently than the merchant sailing ships of the 18th and 19th centuries?






3. Maps A and B show two marine surveys.  Notice that the scales differ on the maps.  Contrast the two searches in terms of the following:

·       Track length

·       Track spacing

·       Turns

·       Perpendicular lines

Can you speculate on why the searches are different?




4.  Map A shows a drift model for a ship in the ocean.  There are three colored vectors (blue, green, and orange), and a resultant in red.  What  do the three vectors represent, and why did you make those identifications.



Map B shows a black trapezoid.  What does it show, and why would it be done?



Map C shows a number of colored points.  How were they generated, and what do they show?







5.  These three figures all represent depictions of the same data set.


·       How can we collect this data?

·       When in the process of searching will this technique be used, and why is it valuable then?

·       What is the difference in the three depictions?



Insure you answered 4 of the 5 diagrams.