how did europe's peninsulas help it expand, considering economics and ideas etc?
Humans' first sailing ships are thought to have been sailed only on rivers and right along coastlines until people learned how to navigate away from sight of land.
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Boat & ship types
The first Egyptian sailing ships existed around 3000 BC or even earlier. They were used on the Nile River, which was ideal for primitive sailing vessels. ...
http://www.abc.se/~pa/bld/shiptype.htm
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Ships: a Timeline
what were probably the first sailing boats. ... 1450 onwards: Three and four masted sailing ships were in service for several centuries. ...
http://www.kidcyber.com.au/topics/shipstimeline.html
Take a good look at a map of the Mediterranean Sea:
http://www.google.com/search?q=mediterranean+sea+map&ie=utf-8&oe=utf-8&aq=t&client=firefox-a&rlz=1R1GGGL_en___US357
With all those peninsulas and islands, a great deal of sailing was able to to on within sight of land. That was just the beginning.