Viking longships and knorrs.
The Vikings were, apart from their other qualities, excellent shipwrights and sailors. They sailed south and east along Europe's coasts as far as the Black Sea and Turkey, and north and west to Greenland and Newfoundland.
For more information about their astonishing culture, see: www.bbc.co.uk/history/ancient/vikings/index.shtml
As they had no saws, only axes, chisels, knives and adzes (http://en.wikipedia.org/wiki/Adze) were available for their woodwork.
To build their ships they used straight oak trunks, which were split to rather thick boards and then smoothed with the adze. The ships were clinker-built (http://en.wikipedia.org/wiki/Clinker_(boat_building)) and thus needed only relatively thin boards; nevertheless they were sturdy enough to survive wild seas and light enough to be dragged overland.
They can be devided in two types: the longship, low-slung and slender, used for raids, warfare, to show off and to be buried in when the warlord died, and the knorr, the workhorse: a deeper hull for heavy loads, and a much wider beam.
The Vikings also innovated on the use of the square sail: first they used a long boom (beitass) to push the luff further forward when tacking, which was later replaced by bowlines with the same function. Beating windward to sixty degrees they kept speed; a longship replica, built in 1893, sailed (mostly upwind) to America in 28 days, a remarkable feat!
For pictures and video's, see:
http://www.vikingeskibsmuseet.dk/index.php?id=1276&L=1 (a Danish site, but partly in English).
And to amuse you, the site of a Dutch sailor who built his own replica's: www.vikingorm.nl/EN_Page_Orm.htm.