How many Whaleback ships are left?
Of the larger whalebacks, which continued in Lake service, only four still remain. The last whaleback steamer under the American flag, built in 1896 as the Frank Rockefeller, served for a time as the automobile carrier South Park and is still in service as the lake oil tanker Meteor.
What is a Whaleback boat?
A whaleback was a type of cargo steamship of unusual design, with a hull that continuously curved above the waterline from vertical to horizontal. When fully loaded, only the rounded portion of the hull (the “whaleback” proper) could be seen above the waterline.
What is a Whaleback deck?
Having an arched or curved deck continuous with the side: said of a particular type of steamer. See whaleback , n., 2. noun Same as turtleback . noun A vessel of which the upper deck is rounded: generally without upper works. Such vessels were first used on the great lakes.
What is whale back in geography?
A streamlined rock knob with symmetrical longitudinal profiles caused by abrasion of both stoss and lee sides. Small whalebacks can form under only a few hundred metres of ice; larger ones under deep ice streams.
How are Whalebacks formed?
It is hypothesised that these whalebacks and rock drumlins develop under ice streams of Greenland or East Antarctic type, sliding rapidly over bedrock and exploiting rock weaknesses to produce streamlined features. Lee slopes are abraded when thick ice suppresses bed separation, even with rapid flow; basal ice of low …
Where do eskers originate?
Eskers are ridges made of sands and gravels, deposited by glacial meltwater flowing through tunnels within and underneath glaciers, or through meltwater channels on top of glaciers. Over time, the channel or tunnel gets filled up with sediments.
Where are eskers found?
Notable areas of eskers are found in Maine, U.S.; Canada; Ireland; and Sweden. Because of ease of access, esker deposits often are quarried for their sand and gravel for construction purposes.
What are sunken drumlins?
Drumlins are elongated, teardrop-shaped hills of rock, sand, and gravel that form from the movement of glaciers, according to the National Snow and Ice Center. They are typically oblong, two or three times longer than they are wide.
What is a Drumland?
drumlin, oval or elongated hill believed to have been formed by the streamlined movement of glacial ice sheets across rock debris, or till. The name is derived from the Gaelic word druim (“rounded hill,” or “mound”) and first appeared in 1833. Drumlin.
Why are eskers sinuous?
Most of the Mason esker has been removed, its sand and sorted gravel used to make concrete highway construction. The ice that formed the sides and roof of the tunnel subsequently disappears, leaving behind sand and gravel deposits in ridges with long and sinuous shapes.