"Sailgating” (sail + tailgating) is when a tailgate picnic is held from a boat instead of a car, van, or pickup truck. Sailgating can involve any boat—not just sailboats. The tradition appears to have started at the University of Washington and is also practiced at the University of Tennessee.
The New York (NY) Times wrote about Washington’s tradition on October 13, 2011:
“Once docked or anchored, they tailgate with a twist, a practice the locals have alternately called boatgating, sailgating and sterngating.”
The word “sailgating” has been cited in print since at least 1991, “sterngating” has been cited in print since 1994 and “boatgating” has been cited in print since 1996. Sailgating differs from tailgating in that sailgating usually has less grilling of foods (to prevent boat fires).
13 October 1991, Atlanta (GA) Journal-Constitution, “Forget hot dogs, forget the game: Let’s tailgate!”, pg. M1:
When 95000 Volunteer fans jam Neyland Stadium in Knoxville, scores of UT faithful avoid the traffic by sailgating—docking their boats behind the grandstand on the Tennessee River.
Seattle (WA) Times
Friday, December 20, 2002 - Page updated at 12:00 AM
Restaurateur John Franco helped ease liquor laws
By Kristina Shevory
Seattle Times Eastside business reporter
Many Seattleites will remember John Franco as the legendary restaurateur who operated Franco’s Hidden Harbor restaurant and helped legalize the sale of liquor by the drink.
In 1956 the veteran restaurateur started the local tradition of “sailgating,” or taking customers by boat to Husky Stadium for football games. Brunch would be served on the way to the game, and appetizers and drinks on the way back to the restaurant.
The Times-Picayune (New Orleans, LA)
LSU football fans opt for ‘sailgating’ off Lake Washington
By Jennifer Armstrong, Nola.com | The Times-Picayune
on September 06, 2009 at 2:04 AM, updated September 06, 2009 at 2:10 AM
SEATTLE—For some fans, moving the cherished pregame ritual off land could prove daunting. Not for LSU fans.
Hordes of them took over rental boats, yachts and sloops Saturday and cruised into Union Bay off Lake Washington next to Husky Stadium. The gleaming inlet is the spot where Washington fans “sailgate.”
When a large group of sailboats gather in the bay. Until they all run out of beer. Tailgating for sailboats.
They’re all sailgating in The Gulf of Mexico.
by TheRiverviewGirls Apr 28, 2010
New York (NY) Times
Tailgating Crowd’s Unlikely Roar: Ahoy!
By GREG BISHOP
Published: October 13, 2011
SEATTLE — The University of Washington’s football stadium loomed ahead, beyond the traffic, as the Miles family steered toward its usual parking spot one Saturday last month. For 50 years, the family members have arrived at Huskies home games through this entrance the same way: grill gassed, coolers stocked with microbrews, clad entirely in purple.
Their routine would seem like a typical tailgate, if only there were cars.
Once docked or anchored, they tailgate with a twist, a practice the locals have alternately called boatgating, sailgating and sterngating.
Husky Stadium opened in 1920, and soon after, the boat tradition started, with fans stashing vessels in tall grass not 200 yards from the end zone. Docks were built around 1960, according to Dave Torrell, the curator of the university’s hall of fame, and early transportation from anchored boats often came from members of the rowing teams in exchange for tips.
One of the Most Unique Ways to Tailgate Revealed: Boatgating
Discover Boating names best stadiums for the latest trend in on-water tailgating.
Chicago, IL (PRWEB) August 23, 2012
Boatgating, also dubbed sailgating, stern-gating or transom-gating, has become a unique way for boaters and sports fans to experience the tradition of tailgating with an extra element of fun. Game day starts and ends with a relaxing cruise on the water, much more enjoyable than sitting in pre- or post-game traffic. For those with boats furnished with access to a grill, refrigerator and ample seating area, boatgating becomes even more convenient. No lugging of grills, chairs or other cooking gear when it’s all on board.