The IMSHOF founded and a panel of selectors (Commander Gerald Forsberg, OBE, Master Mariner, FNI, Royal Navy (Retired) of England, Buck Dawson of the International Swimming Hall of Fame in Florida and Joe Grossman) named “classes” of six Honorees for each year from 1963 (when the World Professional Marathon Swimming Federation began to collect paper based historical data on the sport) through 1970. A marathon swim was defined as 10 miles (+)/16.1 km.
Gerald continued to lead the organization and new Inductees were nominated and selected in consultation with an ad-hoc group of current Honorees. The definition of a marathon swim was changed to 25 km (+) in the late 1980s following FINA interest and first events in the sport. Starting in 1994 Certificates of Merit were issued to swimmers and contributors - recognition below the level of Honoree.
Dale Petranech was the Honorary Secretary and Kevin Murphy continued as the non-executive Honorary Chair . The selection was formalized using ballots and selector included a broader geographic representation and the first non-Inductees. Dale with help from the ISHOF organized the first ever IMSHOF Induction Ceremonies - modest events in Florida around the larger ISHOF annual event. Steven Muñatones joined Dale in 2003 and led the drive to move and expand the paper records to the web including www.openwaterpedia.com and the first IMSHOF website.
The definition of a marathon swim was changed to 10 km (+) in 2005 to include the 10k marathon swim in the Olympics which provided further prestige to the sport and to the IMSHOF. Christopher Guesdon joined Dale and Steven in 2009 to manage the selection process.
2011 – 2014
The IMSHOF was an independent non-profit organization, maintaining a close working relationship with the ISHOF. In 2014 the management team consisted of:
Chief Administrator: Steven Muñatones (USA)
Secretary/Treasurer: Dale Petranech (USA)
Programme Vice President: Christopher Guesdon (AUS)
President: Kevin Murphy (GBR)
Chairman Emeritus (non voting): Conrad Wennerberg (USA)
Area Vice-Presidents: Europe - Stéphane Lecat (FRA); North America - Lynn Blouin (CAN), Oceania - Philip Rush (NZL) and South America - Silvia Dalotto (ARG); Asia - Yuko Matsuzaki (JAP); Africa - Neville Smith (RSA) and Wayne Ridden (RSA)
A Board of Directors (served as the selectors) was expanded and names published.
The Record a Swim program was created to capture historic records of marathon swims, especially where no local open water organization was in place. Certificates were issued for swims from 1979 to 2013. This was not a ratification/certification program – rather it is simply relied on swimmer full disclosure/honesty to help IMSHOF create a historic database. Starting in the UN in New York in 2011 much larger/more formal Induction and Awards Ceremonies were held annually. Ned Denison joined after this to assemble the Honoree list, contact details and first newsletters. The definition of a marathon swim was changed to 10 km (+) during this period in recognition that the Olympic 10 km was universally agreed by FINA and the public to be a marathon swim.
2014 to Present
In 2014, the IMSHOF once again joined the ISHOF as a formal division of its organization and all the previous organization structures ended. These include the previous Board of Directors, the Certificates of Merit program as they diluted the branding of IMSHOF Honorees and the Record a Swim program also for brand dilution reasons and Openwaterpedia had become a historical reporting reference.
A larger, more formal Executive Committee now helps directs and manages the operation of the IMSHOF. A new website was created, tightly linked with www.openwaterpedia.com and www.longswims.com with expanded biographies of all Honorees with associated videos, photos, painting and/or drawings. A Facebook page and Instagram operates and members are also contacted annually through email and newsletters. The induction ceremony in 2017 saw the largest assembly ever of 17 individual Honorees and 7 Honor Organizations.