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# Category Archives: Maritime

## Binnacle

Photo by RK

### Here we see Boston Harbor – now let’s get in to how the binnacle works!

This map is from mass.gov/eea/images/dcr

## Why did we need to develop the binnacle?

Excerpted from Magnetic Deviation: Comprehension, Compensation and Computation by Ron Doerfler

## Magnetic Variation

### We now know that the locations of the Earth’s magnetic poles are not coincident with the geographic poles—not even close, really—and they are always wandering around.

Image from commons.wikimedia.org, Magnetic_North_Pole_Positions. Red circles mark magnetic north pole positions as determined by direct observation, blue circles mark positions modelled using the GUFM model (1590–1980) and the IGRF model (1980–2010) in 2 year increments.

### There’s also a special line where the magnetic north and geographic north point in the same direction.

Image from Drillingformulas.com by Rachain J i

### Here we can see how many degrees of deviation there are – the # of degrees between where the compass points, and where the north pole is. But – wait for it – the image is changing? The magnetic fields are significantly changing every year!

from USGS.gov, faqs, what is declination

## Magnetic Deviation

Ron Doerfler writes

### The first notice in print of this effect was by Joao de Castro of Portugal in 1538, in which he identified “the proximity of artillery pieces, anchors and other iron” as the source.

As better compass designs appeared, a difference in compass readings with their placement on the same ship became more apparent. Captains John Smith and James Cook warned about iron nails in the compass box or iron in steerage, and on Cook’s second circumnavigation William Wales found that changes in the ship’s course changed their measurements of magnetic variation by as much as 7°.

### Here we see a modern naval vessel, with it’s own magnetic field. As a metal ship moves through Earth’s magnetic field, an electric current is produced within all that metal – and that current produces it’s own magnetic field. This field can affect the ship’s compass. That’s why a binnacle is designed to be adjustable, to compensate for this field. – RK

image from slideplayer.com/slide/1632522/

Ron Doerfler writes

## Apps & Interactives

NOAA Historical Magnetic Declination

## Activities

https://oceanservice.noaa.gov/education/lessons/plot_course.html

## Educational opportunities and museums

http://www.capecodmaritimemuseum.org/education/

http://abycinc.org/?page=standards

## Important components

Hood, over the compass bowl

flinders bar (vertical, soft iron corrector)

## Learning Standards

Ocean Literacy Scope and Sequence for Grades K-12
6. The ocean and humans are inextricably interconnected: From the ocean we get foods, medicines, and mineral and energy resources. In addition, it provides jobs, supports our nation’s economy, serves as a highway for transportation of goods and people, and plays a role in national security.

Massachusetts 2016 Science and Technology/Engineering (STE) Standards
7.MS-PS2-5. Use scientific evidence to argue that fields exist between objects with mass, between magnetic objects, and between electrically charged objects that exert force on each other even though the objects are not in contact.

HS-PS2-1. Analyze data to support the claim that Newton’s second law of motion is a mathematical model describing change in motion (the acceleration) of objects when acted on by a net force….{forces can include magnetic forces}

HS-PS3-5. Develop and use a model of magnetic or electric fields to illustrate the forces and changes in energy between two magnetically or electrically charged objects changing relative position in a magnetic or electric field, respectively.

## History standards

National Standards for History Basic Edition, 1996
5-12 Identify major technological developments in shipbuilding, navigation, and naval warfare and trace the cultural origins of various innovations.

Massachusetts History and Social Science Curriculum Framework
The Political, Intellectual and Economic Growth of the Colonies. Explain the importance of maritime commerce in the development of the economy of colonial Massachusetts, using historical societies and museums as needed.

National Curriculum Standards for Social Studies: A Framework for Teaching, Learning, and Assessment, National Council for the Social Studies, 2010.

## Model ship building in Boston

### My father grew up on Boston Harbor. In addition to being a soldier, and an engineer with a research think tank, he did ship modeling at the USS Constitution Museum.

In the USS Constitution Museum workshop, 1990’s.

Front view

## Scale conversion factors

### Table of Scale Conversion Factors

from to 1/8 to 3/16 to 1/4
1/16 2.0 3.0 4.0
1/12 1.5 2.25 3.0
3/32 1.33 2.0 2.67
1/8 1.0 1.5 2.0
5/32 0.8 1.2 1.6
3/16 0.67 1.0 1.33
1.5 0.625 0.94 1.25
7/32 0.57 0.86 1.14
1/4 0.5 0.75 1.0

### In this example we want to estimate its size as a model. We find that the length is given at 136 ft 7 in, which rounds off to 137 feet.

 1/8 scale Feet divided by 8 3/16 scale Feet divided by 5.33 1/4 scale Feet divided by 4

### Although this technique allows you to judge the approximate length of a proposed model from its true footage, only square riggers will fit the approximate height and beam by the above factors. To approximate these dimensions on other craft, scale the drawings from which you found the length and arrive at her mast heights and beam.

Reference: Williams, Guy R. The World of Model Ships and Boats London 1971 Page 30

The USS Constitution Model Shipwright Guild

We are the largest model ship association on the East Coast and our friendly meetings overlooking Old Ironsides at the USS Constitution Museum are well attended. Novices and experienced model builders alike can have fun developing resources, experiences, and skills by joining us.

The USS Constitution Museum, located in the Charlestown Navy Yard, which is part of the Boston National Historical Park

The USS Constitution Museum serves as the memory and educational voice of USS Constitution, by collecting, preserving, and interpreting the stories of “Old Ironsides” and the people associated with her.

The science and history of the sea

https://en.wikipedia.org/wiki/Ship_model

https://en.wikipedia.org/wiki/Wooden_ship_model

## Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

Massachusetts History and Social Science Curriculum Frameworks

5.11 Explain the importance of maritime commerce in the development of the economy of colonial Massachusetts, using historical societies and museums as needed. (H, E)

5.32 Describe the causes of the war of 1812 and how events during the war contributed to a sense of American nationalism. A. British restrictions on trade and impressment.  B. Major battles and events of the war, including the role of the USS Constitution, the burning of the Capitol and the White House, and the Battle of New Orleans.

National Council for the Social Studies: National Curriculum Standards for Social Studies

Time, Continuity and Change: Through the study of the past and its legacy, learners examine the institutions, values, and beliefs of people in the past, acquire skills in historical inquiry and interpretation, and gain an understanding of how important historical events and developments have shaped the modern world. This theme appears in courses in history, as well as in other social studies courses for which knowledge of the past is important.

A study of the War of 1812 enables students to understand the roots of our modern nation. It was this time period and struggle that propelled us from a struggling young collection of states to a unified player on the world stage. Out of the conflict the nation gained a number of symbols including USS Constitution. The victories she brought home lifted the morale of the entire nation and endure in our nation’s memory today. – USS Constitution Museum, National Education Standards

Common Core ELA: Reading Instructional Texts

CCSS.ELA-LITERACY.RI.9-10.1
Cite strong and thorough textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text.

CCSS.ELA-LITERACY.RI.9-10.4
Determine the meaning of words and phrases as they are used in a text, including figurative, connotative, and technical meanings

Common Core ELA Writing

CCSS.ELA-LITERACY.W.9-10.1.C
Use words, phrases, and clauses to link the major sections of the text, create cohesion, and clarify the relationships between claim(s) and reasons, between reasons and evidence, and between claim(s) and counterclaims.

CCSS.ELA-LITERACY.W.9-10.1.D
Establish and maintain a formal style and objective tone while attending to the norms and conventions of the discipline in which they are writing.

CCSS.ELA-LITERACY.W.9-10.4
Produce clear and coherent writing in which the development, organization, and style are appropriate to task, purpose, and audience.

## News story from WCVB

http://www.wcvb.com/article/1065-foot-container-ship-breaks-free-from-boston-terminal/14186750

A container ship broke free from a terminal in Boston, the Coast Guard confirmed early Wednesday morning. The 1,065-foot ship “Helsinki Bridge” was at the Paul W. Conley Container Terminal when the 12 lines securing the vessel broke.

“They notified us very quickly. The ship’s crew was very quick in getting their engine equipment up and running so that they could drop their anchor and not be drifting around,” Coast Guard Lt. Jennifer Sheehy said.

Terminal workers who were on the ship were able to get off, and no injuries were reported. Two tug boats and a pilot helped to escort the runaway ship out to Broad Sound, between Winthrop and Nahant. State police said the ship hit a dock and did some minor damage when it broke free.

“They’ll take a look at all of the equipment.  They’ll talk to the ship’s crew, and a team is at Conley Terminal looking at any damage that might be there,” Sheehy said.

Officials said weather may have played a role in the ship breaking free.  “Winds that we had last night, the strength of those winds and a ship this size has a lot of sail area to push against, so it’s not unheard of for a ship this size to part ways because of the wind strength,” Sheehy said. The ship will eventually be towed back to the terminal.

## Learning Standards

Ocean Literacy Scope and Sequence for Grades K-12

http://oceanliteracy.wp2.coexploration.org/ocean-literacy-framework/

Ocean Literacy Principle #3, The ocean interaction of oceanic and atmospheric processes controls weather and climate by dominating the Earth’s energy, water and carbon systems.

Ocean Literacy Principle #6,

b. The ocean provides foods, medicines, and mineral and energy resources. It supports jobs and national economies, serves as a highway for transportation of goods and people, and plays a role in national security.

f. Much of the worlds population lives in coastal areas. Coastal regions are susceptible to natural hazards (tsunamis, hurricanes, cyclones, sea level change, and storm surges).

## The Science and History of the Sea

### Session 1: TBA at the USS Constitution Museum. Museum staff led.

Introductory movie (10 minutes)

• Design your own frigate based on the templates of Constitution’s ship designer Joshua Humphreys: Students will produce drawings.
• Made in America – what materials were used to create the USS Constitution? Students will create a list of 5 materials from the New England region.
• Which of these woods is the hardest? Through dropping balls into difference woods, we can study the difference in how the ball bounces back. The kinetic energy of the rebounding ball is related to the amount of energy absorbed by the wood. See the difference between kinetic energy and potential energy.
• Test your ship against other frigates in this hands-on challenge. Choose between three different types of ships for the ultimate test of size, speed and power: An interactive computer simulation.
• What’s so great about copper? Learn about the metals used in construction
• Build a ship: Assemble 2D pieces into a 3D model – how quickly can they accurately complete the task?
• Construction and launch: View this video, and then explain how a ship is safely launched from a drydock into the ocean.  Students will demonstrate that they understand the procedure by writing a step-by-step paragraph explaining the sequence.
• How can a ship sail against the wind? Through a hands on experiment, see how changing the angle of the sail affects the motion of the boat: Students should be able to explain in complete sentences how the same wind can make a ship move forwards or backwards.
• On the 2nd story of the museum, operate a working block-and-tackle system. This uses a classic simple machine. It is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift or pull heavy loads. Back in the school building, we’ll review each of the classic simple machines.

On the 2nd story of the museum, operate a working block-and-tackle system. This uses a classic simple machine: pulleys with a rope or cable threaded between them, to lift or pull heavy loads.

### As students tour the visitor center, they practice ELA reading and writing skills (listed below) by briefly summarizing something they learn from each of these sections: They are encouraged to create drawings/tracings as they see fit to help illustrate their text.

• Describe how ropes are made from string in the ropewalk
• From wood & sail to steel & steam
• Preparing for new technology
• The shipyard in the Civil War
• Ships and shipbuilding
• The Navy Yard 1890-1974
• Chain Forge and Foundary
• The Navy Yard during World Wars I and II
• Shipyard workers 1890 to 1974
• The shipyard during the Cold War era 1945-1974

### This teaching supplement contains math lessons organized in grade-level order. However, because many of the math skills used in these lessons are taught in multiple grades, both grade-level and lesson content are listed below.

Estimating Numbers of Objects

Estimating and Comparing Numbers of Objects

Estimating and Comparing Length, Width and Perimeter

Computing Time and Creating a Schedule

Drawing Conclusions from Data Sets

Creating and Interpreting Graphs from Tables

Range, Mean, Median and Mode and Stem-and-Leaf Plots

Converting Between Systems of Measurement

Calculating Volume

Describing Distance and Velocity Graphs

Writing Linear Equations

Using Projectile Motion to Explore Maximums and Zeros

Using Parabolic Equations & Vectors to Describe the Path of Projectile Motion

## Learning Standards

MA 2006 Science Curriculum Framework

2. Engineering Design. Central Concept: Engineering design requires creative thinking and consideration of a variety of ideas to solve practical problems. Identify tools and simple machines used for a specific purpose, e.g., ramp, wheel, pulley, lever.

Massachusetts Science and Technology/Engineering Curriculum Framework

HS-ETS4-5(MA). Explain how a machine converts energy, through mechanical means, to do work. Collect and analyze data to determine the efficiency of simple and complex machines.

Benchmarks, American Association for the Advancement of Science

In the 1700s, most manufacturing was still done in homes or small shops, using small, handmade machines that were powered by muscle, wind, or moving water. 10J/E1** (BSL)

In the 1800s, new machinery and steam engines to drive them made it possible to manufacture goods in factories, using fuels as a source of energy. In the factory system, workers, materials, and energy could be brought together efficiently. 10J/M1*

The invention of the steam engine was at the center of the Industrial Revolution. It converted the chemical energy stored in wood and coal into motion energy. The steam engine was widely used to solve the urgent problem of pumping water out of coal mines. As improved by James Watt, Scottish inventor and mechanical engineer, it was soon used to move coal; drive manufacturing machinery; and power locomotives, ships, and even the first automobiles. 10J/M2*

The Industrial Revolution developed in Great Britain because that country made practical use of science, had access by sea to world resources and markets, and had people who were willing to work in factories. 10J/H1*

The Industrial Revolution increased the productivity of each worker, but it also increased child labor and unhealthy working conditions, and it gradually destroyed the craft tradition. The economic imbalances of the Industrial Revolution led to a growing conflict between factory owners and workers and contributed to the main political ideologies of the 20th century. 10J/H2

Today, changes in technology continue to affect patterns of work and bring with them economic and social consequences. 10J/H3*

Massachusetts History and Social Science Curriculum Frameworks

5.11 Explain the importance of maritime commerce in the development of the economy of colonial Massachusetts, using historical societies and museums as needed. (H, E)

5.32 Describe the causes of the war of 1812 and how events during the war contributed to a sense of American nationalism. A. British restrictions on trade and impressment.  B. Major battles and events of the war, including the role of the USS Constitution, the burning of the Capitol and the White House, and the Battle of New Orleans.

National Council for the Social Studies: National Curriculum Standards for Social Studies

Time, Continuity and Change: Through the study of the past and its legacy, learners examine the institutions, values, and beliefs of people in the past, acquire skills in historical inquiry and interpretation, and gain an understanding of how important historical events and developments have shaped the modern world. This theme appears in courses in history, as well as in other social studies courses for which knowledge of the past is important.

A study of the War of 1812 enables students to understand the roots of our modern nation. It was this time period and struggle that propelled us from a struggling young collection of states to a unified player on the world stage. Out of the conflict the nation gained a number of symbols including USS Constitution. The victories she brought home lifted the morale of the entire nation and endure in our nation’s memory today. – USS Constitution Museum, National Education Standards

Common Core ELA: Reading Instructional Texts

CCSS.ELA-LITERACY.RI.9-10.1
Cite strong and thorough textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text.

CCSS.ELA-LITERACY.RI.9-10.4
Determine the meaning of words and phrases as they are used in a text, including figurative, connotative, and technical meanings

Common Core ELA Writing

CCSS.ELA-LITERACY.W.9-10.1.C
Use words, phrases, and clauses to link the major sections of the text, create cohesion, and clarify the relationships between claim(s) and reasons, between reasons and evidence, and between claim(s) and counterclaims.

CCSS.ELA-LITERACY.W.9-10.1.D
Establish and maintain a formal style and objective tone while attending to the norms and conventions of the discipline in which they are writing.

CCSS.ELA-LITERACY.W.9-10.4
Produce clear and coherent writing in which the development, organization, and style are appropriate to task, purpose, and audience.

The USS Constitution Museum, located in the Charlestown Navy Yard, which is part of the Boston National Historical Park

## From a Navy munitions bunker to a school

### In our hands-on program, Seaport students weave together academic classes with exploration of the seafront, build bikes and chairs, experiment with aquaculture, learning fishing and boating, water chemistry experiments – and basketball. Hands-on, our experiential programs lets students rediscover what it means to enjoy learning, and to grow personally and academically.

Seaport Academy classroom. Photo by Richard Howard

### More progress

Naval Hospital Boston Historic District

Naval Hospital Boston Historic District (Chelsea Naval Hospital)

Charlestown Navy Yard Historic Resource Study, by the National Park Service

The USS Constitution Museum, located in the Charlestown Navy Yard, which is part of the Boston National Historical Park

The USS Constitution, the oldest commissioned warship afloat. Official US Navy website

## Mirages

A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky.

The word comes to English via the French mirage, from the Latin mirari, meaning “to look at, to wonder at”. This is the same root as for “mirror” and “to admire”.

In contrast to a hallucination, a mirage is a real optical phenomenon that can be captured on camera, since light rays are actually refracted to form the false image at the observer’s location.

What the image appears to represent, however, is determined by the interpretive faculties of the human mind. For example, inferior images on land are very easily mistaken for the reflections from a small body of water.

Mirages can be categorized as:

“inferior” (meaning lower)

“superior” (meaning higher)

“Fata Morgana”, one kind of superior mirage consisting of a series of unusually elaborate, vertically stacked images, which form one rapidly changing mirage.

Mirage. (2016, December 18). In Wikipedia, The Free Encyclopedia.

Problems

According to legend, Erik the Red sailed from Iceland and discovered Greenland after he had seen the island in a mirage. Describe how the mirage might have occurred.

Well, that answer from our textbook teacher editions, however true, isn’t very helpful. It’s not clear what we are looking at. Let’s look at a much better picture to see both the problem and the solution.

Problem: Erik the Red shouldn’t be able to see Greenland from where he is standing, on Iceland. Greenland is so far away that it is over the curve of the Earth (over the horizon.)

Solution:

The superior mirage, also know in northern polar regions as the arctic mirage — or in Icelandic, the hillingar effect — causes the light from distant objects to be optically refracted downward

Thus it becomes possible for objects lying beyond the normal horizon to be seen.

(They even appear, at times, to rise up over the horizon, a condition known to mariners as looming, and look much closer in distance.)

Fata Morgana Mirage in Greenland, 1999, by Jack Stephens

SEE BELOW FOR THE FAMOUS MOBY DICK MIRAGE

The arctic mirage, on the other hand, occurs when the light rays are refracted downward by cold, dense air near the earth into an arc bending toward the observer. (In the diagrams accompanying this article, the dark lines indicate the actual light ray path and the white dashed lines the path our mind thinks it sees.)

The refractivity of air — a measure of the air’s ability to bend the path of light rays — is dependent upon its density, and the density of air is inversely related to its temperature (decreasing as temperature increases). The atmospheric conditions for producing the arctic mirage occur when cool air adjacent to the surface underlies warm air. When the air temperature increases with altitude, the condition is known meteorologically as a temperature inversion.

When the temperature of the lower atmosphere increases with altitude at a rate of 11.2 C° per 100 metres (6.0 F° per 100 ft), the refractive capacity of the air is great enough to cause the path of light rays to bend in an arc equal to the curvature of the Earth. This curvature can present an observer with the image of a flat horizon receding to infinity. A temperature gradient greater than 11.2 C° per 100 m causes light ray paths to exceed the curvature of the Earth, and thus the horizon would appear to be raised upward giving the Earth’s surface a saucer-shaped appearance. Under this latter condition, images of objects located at or below the normal optical horizon, such as mountains, glaciers, cliffs or sea-ice rise (loom) into the field of vision, overcoming the normal visual restrictions of the curvature of the Earth.

The normal viewing distance at the surface of the earth depends upon the height of the object being observed and the height of the observer. Disregarding atmospheric effects on light rays, the curvature of the earth restricts the distance one can see from the surface. For example, a beach or small iceberg rising 3.0 to 3.7 m (10 to 12 ft) above the sea surface can be seen from the surface at a distance of no more than 19.2 km (12 miles) through a clear, normal atmosphere. A mountain peak of 914 metres (3,000 feet) would disappear at 115 kilometres (72 miles) distant, one 1520 m (5,000 ft) tall at 150 km (94 miles).

The maximum viewing distance under arctic mirage conditions, on the other hand, is limited only by the light absorption of the atmosphere. Near sea level, the transmission of light is generally of sufficient quality to enable the naked eye to potentially see objects at a distance of up to 400 km (250 miles). However, when the refracting layer is at the upper boundary of a very deep cold layer, the thinner air may permit more light to be transmitted, thus making visibility in excess of 400 km possible.

Under arctic mirage conditions, instances of atmospheric visibility extending 320 km (200 miles) have been reported. In 1937 and 1939, W.H. Hobbs documented several occasions during which objects were sighted at distances well in excess of those possible under normal viewing conditions.

Answer text from The Arctic Mirage. Aid to Discovery. The Weather Doctor.

## Moby Dick illusion

James Rickards writes

One famous literary description of a Fata Morgana occurs in Chapter 135 of Herman Melville’s masterpiece, Moby Dick. As Ahab is pulled overboard, and the White Whale rams the Pequod, Melville writes:

“The ship? Great God, where is the ship? Soon they through dim, bewildering mediums saw her sidelong fading phantom, as in the gaseous Fata Morgana.”

But, of course the ship was sinking, the vision was an illusion.

## Amazing examples

A Ship Floating In Mid-Air At A Scottish Golf Tournament?

Just like the above mentioned mirages!

Enter a caption

image: Tom Phillips/BuzzFeed/ilyast/syntika/Thinkstock

## Floating boats and islands

Video

Island and fishing boat mirage

Fata Morgana Mirage at Cocoa Beach, FL!

Lake Superior Marquette, MI 05.23.15 – first scene is real time, freighter in to Marquette, second is timelapse, Granite Island looking like a lava lamp

An Introduction to Mirages, Andrew T. Young

Fata Morgana between the Continental Divide and the Missouri River

## Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

HS-PS4-3. Evaluate the claims, evidence, and reasoning behind the idea that electromagnetic radiation can be described by either a wave model or a particle model, and that for some situations involving resonance, interference, diffraction, refraction, or the photoelectric effect, one model is more useful than the other.

A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012)

Core Idea PS4: Waves and Their Applications in Technologies for Information Transfer
When a wave passes an object that is small compared with its wavelength, the wave is not much affected; for this reason, some things are too small to see with visible light, which is a wave phenomenon with a limited range of wavelengths corresponding to each color. When a wave meets the surface between two different materials or conditions (e.g., air to water), part of the wave is reflected at that surface and another part continues on, but at a different speed. The change of speed of the wave when passing from one medium to another can cause the wave to change direction or refract. These wave properties are used in many applications (e.g., lenses, seismic probing of Earth).

The wavelength and frequency of a wave are related to one another by the speed of travel of the wave, which depends on the type of wave and the medium through which it is passing. The reflection, refraction, and transmission of waves at an interface between two media can be modeled on the basis of these properties.

All electromagnetic radiation travels through a vacuum at the same speed, called the speed of light. Its speed in any given medium depends on its wavelength and the properties of that medium. At the surface between two media, like any wave, light can be reflected, refracted (its path bent), or absorbed. What occurs depends on properties of the surface and the wavelength of the light.

SAT Subject Area Test in Physics

Waves and optics:

• Reflection and refraction, such as Snell’s law and changes in wavelength and speed
• Ray optics, such as image formation using pinholes, mirrors, and lenses