Images of Old Hawaiʻi

  • Home
  • About
  • Categories
    • Ali’i / Chiefs / Governance
    • American Protestant Mission
    • Buildings
    • Collections
    • Economy
    • Missionaries / Churches / Religious Buildings
    • General
    • Hawaiian Traditions
    • Other Summaries
    • Mayflower Summaries
    • Mayflower Full Summaries
    • Military
    • Place Names
    • Prominent People
    • Schools
    • Sailing, Shipping & Shipwrecks
    • Voyage of the Thaddeus
  • Collections
  • Contact
  • Follow

August 1, 2023 by Peter T Young Leave a Comment

Currents

Historically the world was thought of having 4 oceans the Pacific, Atlantic, Indian and Arctic. Today we have five oceans (adding the Southern (around Antarctica)) covering over 71 percent of the earth’s surface and over 97 percent of the earth’s water. (National Geographic)

The term ‘Seven Seas’ has referred to bodies of water along trade routes, regional bodies of water, or exotic and far-away bodies of water.

In Greek literature (which is where the phrase entered Western literature), the Seven Seas were the Aegean, Adriatic, Mediterranean, Black, Red and Caspian seas, with the Persian Gulf thrown in as a “sea.”

In Medieval European literature, the phrase referred to the North Sea, Baltic, Atlantic, Mediterranean, Black, Red and Arabian seas.

As trade picked up across the Atlantic, the concept of the Seven Seas changed again. Mariners then referred to the Seven Seas as the Arctic, the Atlantic, the Indian, the Pacific, the Mediterranean, the Caribbean and the Gulf of Mexico.

Not many people use this phrase today, but you could say that the modern Seven Seas include the Arctic, North Atlantic, South Atlantic, North Pacific, South Pacific, Indian and Southern Oceans.  (NOAA)

Oceans have currents, the continuous, predictable, directional movement of seawater driven by gravity, wind and water density. Ocean water moves in two directions: horizontally and vertically. Horizontal movements are referred to as currents, while vertical changes are called upwellings or downwellings. (National Geographic)

Ocean currents exist both on and below the surface. Some currents are local to specific areas, while others are global. And they move a lot of water. The largest current in the world, the Antarctic Circumpolar Current, is estimated to be 100 times larger than all the water flowing in all the world’s rivers.

A characteristic surface speed is about 2 to 20 inches per second. Currents generally diminish in intensity with increasing depth.

Vertical movements exhibit much lower speeds, amounting to only a few meters per month. As seawater is nearly incompressible, vertical movements are associated with regions of convergence and divergence in the horizontal flow patterns. (Britannica)

All of this moving water helps more stationary species get the food and nutrients they need. Instead of going looking for food, these creatures wait for the currents to bring a fresh supply to them.

Currents also play a major role in reproduction. The currents spread larvae and other reproductive cells. Without currents many of the ocean’s ecosystems would collapse. (Ocean Blue Project)

Ocean surface currents tend to form ring-like circulation systems called gyres. A gyre is a circular ocean current formed by a combination of the prevailing winds, the rotation of the Earth, and landmasses.

Continents interfere with the movement of both surface winds and currents. Gyres form in both the northern and southern hemispheres.

Gyres in the Northern Hemisphere travel in clockwise directions while gyres in the Southern Hemisphere travel in counter-clockwise directions. It takes about 54 months for water to travel the circuit of the North Pacific gyre, while only 14 months in the North Atlantic gyre.

In the Northern Hemisphere near the equator, trade winds drive currents westward, forming a North Equatorial Current (NE), which moves at about 1 m/sec. At the western boundary of an ocean basin, the water turns and flows towards the North Pole, forming the western-ocean boundary currents.

Western boundary currents are very strong. Two examples are the Gulf Stream (GS) that runs in the Atlantic ocean basin and the Kuroshio Current in the Pacific ocean basin.

They are narrower, but deeper and swifter, than the other currents in the gyre. For example, speeds of 2 m/sec have been measured in the Gulf Stream. These currents, as deep as 1 km, generally remain in deeper water beyond the continental shelf. Western-ocean boundary currents carry warm water from the equator north.

The broad, gentle pitch of the continental shelf gives way to the relatively steep continental slope. The more gradual transition to the abyssal plain is a sediment-filled region called the continental rise. The continental shelf, slope, and rise are collectively called the continental margin. (Britannica)

Eventually, the western boundary currents fall under the influence of the westerly winds and begin flowing to the east, forming the North Atlantic Current (NA) and North Pacific Current (NP).

When they approach the eastern-ocean boundaries of continents, they turn and flow south, forming the eastern-ocean boundary currents. Eastern-ocean boundary currents are shallower and slower than western-ocean boundary currents.

Current flow over the continental shelves (the edge of a continent that lies under the ocean), close to shore, carrying colder waters from the north to the south. Two examples are the California Current (Cal) in the Pacific Ocean basin and the Canary Current (Can) in the Atlantic Ocean basin.

One major current, the equatorial Countercurrent (EC), appears to be an exception to the circulation pattern set up by the gyres. This countercurrent forms just north of the equator in the region between the north equatorial current and the south equatorial current and flows in the opposite direction.  (Hawaii-edu)

© 2023 Ho‘okuleana LLC

Filed Under: General, Sailing, Shipping & Shipwrecks Tagged With: Currents, Seven Seas, Hawaii, North Pacific Gyre, Pacific

November 20, 2018 by Peter T Young Leave a Comment

‘The Longest Way Round Is Frequently The Shortest Way Home’

“(T)he distance between Panama and Yokohama, for example, via Honolulu, is greater than via San Francisco.” So why would ships stop in Hawai‘i?

“(S)hipping routes as well as lovers’ walks by moonlight, ‘the longest way round is frequently the shortest way home.’ The ‘short line’ argument ignores the fact that many things affect and decide routes of travel besides distance.”

“There are three distinct lines of steamer travel across the Pacific, north of the equator, between the American and the Asiatic continents. viz.:”

“(1) The southern route, via Hawai‘i, is in the northeast trade-wind belt, advertised by the Pacific Mail Steamship Company as the ‘Sunshine Belt,’ from the fact that the sun shines along this route during the great majority of the days of the year, and that the normal wind is a gentle breeze varying from ten to twenty knots an hour.”

“Since white men have visited them there has been nothing in the nature of a typhoon or hurricane in the Hawaiian Islands. Even heavy gales are few and far between. and fog is not known there.”

“The Hawaiian Islands and the surrounding ocean are the most favored spot, climatically, on earth.”

“(2) The northern route, from San Francisco, is along the Great Circle line. This is known as the ‘fog belt,’ for the reason that fog is prevalent there during the greater part of the year.”

“The prevailing wind along this line is from the west, and, as a rule. considerably stronger than the trade winds of the southern route. Violent storms are also prevalent along this line.”

“(3) The central route begins at San Francisco, but abandons the Great Circle route and its short distance of 4.536 miles, for a course considerably to the south thereof and making a distance to Yokohama of 4.791 miles, an increase in distance of 255 miles over the northern short line route. “

“This line is recommended by the hydrographic bureau at Washington to steamers crossing the Pacific from San Francisco. The object in taking this longer route is to escape the fog, violent winds and currents and storms of the northern route.”

“It is another demonstration that ‘The longest way round is the shortest way home.’”

“The foregoing demonstrates that although, theoretically, the northern route is 266 miles shorter than the southern, the route actually to be sailed is within eleven miles as long as the southern route.”

“Without looking for any further reasons, the supposed advantages of the northern ‘short line’ route disappear right here. All that remains to be done is to catalogue the many advantages which the southern route, via Hawaii, has over the northern route, via San Francisco.”

“The bulk of transpacific traffic will be carried on in comparatively low-powered freight steamers, making ten to twelve knots an hour, to whom boisterous weather conditions are a serious hindrance.”

“A few days of heavy weather, bucking head seas and winds, and the racing of the propeller as it is pitched up out of water, will use up far more fuel and time on the shorter rough route than will be expended on the longer but smoother route.”

“Stormy, rough weather is in every way detrimental to economical steaming; tends to rack, strain and otherwise injure the ship, with the possibility of wetting and otherwise injuring the cargo, regardless of what direction the wind is from.”

“Under these conditions, other things being equal, or even against a considerable handicap, the smooth water and gentle wind route will be chosen.”

“Practically all of the Pacific Mail and Japanese Mail line steamers plying between San Francisco and Yokohama now travel the ‘sunshine belt,’ via Honolulu, although it is 5,474 miles that way, instead of the direct, ‘fog belt’ route, although it is only 4,536 miles by that course. In other words they prefer a course which is 938 miles the longer.”

“To Hawaii oversea commerce, the arrival and departure of deep sea ships, is the alpha and omega of its commercial existence.”

“Everything that it imports and everything that it exports passes by sea. Every one who goes anywhere and every one who comes from anywhere travels by sea.”

“These conditions have created a habit of mind, a spirit and method of treatment of shipping that markedly characterizes Hawaiian ports.” (Thurston, History of the Panama Canal, 1915)

Follow Peter T Young on Facebook 

Follow Peter T Young on Google+ 

Follow Peter T Young on LinkedIn  

Follow Peter T Young on Blogger

© 2018 Hoʻokuleana LLC

shipping_routes_traffic_density
shipping_routes_traffic_density

Filed Under: General, Sailing, Shipping & Shipwrecks, Economy Tagged With: Transportation, Shipping, Panama, Weather, Wind, Currents, Hawaii

Images of Old Hawaiʻi

People, places, and events in Hawaiʻi’s past come alive through text and media in “Images of Old Hawaiʻi.” These posts are informal historic summaries presented for personal, non-commercial, and educational purposes.

Info@Hookuleana.com

Connect with Us

  • Email
  • Facebook
  • LinkedIn
  • Twitter
  • YouTube

Recent Posts

  • Hawaii and Arkansas
  • Barefoot Football
  • Arthur Akinaka
  • Food Administration
  • Lanai City Schools
  • Happy Mother’s Day!
  • 250 Years Ago … Green Mountain Boys

Categories

  • Place Names
  • Prominent People
  • Schools
  • Sailing, Shipping & Shipwrecks
  • Economy
  • Voyage of the Thaddeus
  • Mayflower Summaries
  • American Revolution
  • General
  • Ali'i / Chiefs / Governance
  • Buildings
  • Missionaries / Churches / Religious Buildings
  • Hawaiian Traditions
  • Military

Tags

Albatross Al Capone Ane Keohokalole Archibald Campbell Bernice Pauahi Bishop Charles Reed Bishop Downtown Honolulu Eruption Founder's Day George Patton Great Wall of Kuakini Green Sea Turtle Hawaii Hawaii Island Hermes Hilo Holoikauaua Honolulu Isaac Davis James Robinson Kamae Kamaeokalani Kamanawa Kameeiamoku Kamehameha Schools Lalani Village Lava Flow Lelia Byrd Liliuokalani Mao Math Mauna Loa Midway Monk Seal Northwestern Hawaiian Islands Oahu Papahanaumokuakea Marine National Monument Pearl Pualani Mossman Queen Liliuokalani Thomas Jaggar Volcano Waikiki Wake Wisdom

Hoʻokuleana LLC

Hoʻokuleana LLC is a Planning and Consulting firm assisting property owners with Land Use Planning efforts, including Environmental Review, Entitlement Process, Permitting, Community Outreach, etc. We are uniquely positioned to assist you in a variety of needs.

Info@Hookuleana.com

Copyright © 2012-2024 Peter T Young, Hoʻokuleana LLC

 

Loading Comments...