By the late 1920s, the NHL had become very concerned about the overly defensive play caused by limited passing rules. So beginning in the 1929-30, the ice was divided into three zones (offensive, neutral and defensive) with forward passing being allowed in all three zones.
The earliest benefactors were the Boston Bruins. They flew to an amazing 38-5-1 record that season. They were led by Hall of Famers Cooney Weiland (league leading 43 goals, 73 points) and Dit Clapper (41 goals, 61 points), two thirds of the "Dynamite Line." The other member of that line was Calgary, Alberta's Dutch Gainor. Gainor, a slick playmaker, scored 18 goals and 31 assists (second in the league to Frank Boucher's 36 helpers) for 49 points in his 3rd NHL season.
Gainor joined the Bruins in 1927 prior to the three zone rule changes, and became a significant contributor the Bruins first Stanley Cup Championship in 1929. Gainor scored 14 times in the regular season and added two more in 5 playoff games.
The Dynamite Line had a short fuse as it turned out. Following their magnificent 1929-30 campaign, NHL teams had learned to combat the three zone rule defensively and the Weiland-Clapper-Gainor line struggled to achieve similar numbers. Weiland only put up 25 goals and Dit Clapper 22, but Gainor struggled the most, scoring only 8 times. More importantly Gainor, who's playmaking style was his forte, only set up 3 other goals.
Gainor was traded to the New York Rangers the following summer in exchange for big, aggressive defenseman Joe Jerwa. Legend has it that the Bruins brain trust, namely Art Ross, didn't like Gainor because of his heavy drinking habits.
Gainor would never again find the success of his incredible 1929-30 season. He struggled with the Rangers before moving on to join the Ottawa Senators and Montreal Maroons, as well as some minor league teams. "Dutch" had a long history of varicose veins which plagued him in his final seasons. By 1935 he was forced to retired because of it, although he would play semi-pro hockey in his native Calgary the next year, as well as putting in a 13 game appearance with the PCHL's Portland Buckaroos.
In all, Norman Gainor played in 246 NHL games, scoring 51 goals and 56 assists for 107 points. He also appeared in 22 playoff games, scoring 2 goals and 1 assist.