According to NHL.com, 637 people have played goal in the NHL. (Note that stats for some early years of the NHL are incomplete.)
Only three have higher career GAA's than Mannino's 13.81:
Greg Redquest 13.85 Penguins 1977-78
James Stewart Jr 15.00 Boston 1979-80
Martin Houle 27.27 Flyers 2006-07 (It's actually listed as 30.00 on his bio of NHL.com. The difference is whether you reflect the seconds he played or just the minutes.)
You could argue that Mammino and Redquest are actually tied. Mannino is credited with 13:02 of ice-time, while Redquest was credited with 13 minutes. Both players allowed three goals.
Save percentage became an official stat about 20 years. The career totals are shown on NHL.com only for players whose entire career happeend while save percentage was an official stat. Of all those players, Mannino has the worst save percentage of all-time: .625 (stopping 5 of 8 shots)
Forever1940 is the nom de plume of Eric Hornick. Eric has worked the Stanley Cup Finals four times, and celebrated his 26th anniversary as the statistician on Islander home telecasts on January 21, 2008.