In this study 100 groups of five participants were used to discover problems with an interface. The study did indeed find that the mean percentage of problems discovered across all 100 groups was about 85%. However, this figure has 95% confidence level and a margin of error of Â±18.5%.
Keelboats were generally built in Pittsburgh, Pennsylvania and it was here that Meriwether Lewis commissioned the boat used by the Corps of Discovery. The keelboat used by the Corps was sketched by Clark in his journal. It was 55 feet long and 8 feet wide, with a 3- to 4-foot draft. For propulsion it had a 32-foot sailing mast, 22 oars, a rudder, and a tiller for steering. Protection against hostile encounters were a swivel cannon on the bow and two smaller guns called blunderbusses.
Winged keel of Australia II. The Winged Keel is a sailboat keel originally designed by Ben Lexcen and made its first appearance on the 12-metre class yacht Australia II in the 1983 America's Cup.Along with Australia II's efficient sail design, this keel was one of the factors contributing to Australia II's success.inged keels are generally found on high performance sailboats, if they are not prohibited by class rules. They are only of benefit for yachts sailing upwind where stability and the ability to produce side force are important and if the draft is limited by the class rule.