I was able to find several records concerning your father.
I found a record of an Ernest Wyman arriving in New York City on 1 July 1943 aboard the ESSO BAYWAY, which had sailed from Glasgow, Scotland, on 16 June 1943. I found another record of an Ernest Harry Wyman arriving in New York City on 5 September 1943, also aboard ESSO BAYWAY, which had sailed from Algiers, Algeria, on a date not specified.
And there is a record for a Ernest H Wyman arriving in Portland, Oregon, on 30 May 1944, aboard the JOHN LYKES, which had sailed from Brisbane, Australia, on a date not specified. The ship had stopped briefly in San Francisco before arriving in Portland. I would guess that JOHN LYKES is the ship that you identify as JOHN LIGHT. JOHN LYKES was a so-called class C-1 cargo ship that also sailed as a troop transport.
In each case he was a member of the Armed Guard unit on the ship in question.
I find records of the GULFBREEZE arriving in New York on a number of dates in 1943 but in each instance your father is not listed among the Armed Guard crew. However, this does not suggest that your information is incorrect, only that the records I found may be incomplete for dates other than 1943.
I would be pleased to post the photographs that you have on the Armed Guard website if you would send electronic copies to me at email@example.com. You cannot post the photographs directly on the website yourself.
I am aware of a merchant marine/Armed Guard training film that is available in VHS or DVD format at http://www.militaryvideo.com/store/store.cfm?titleID=MM1940V&do=detail. This may be the film you mention. The cost is about $30 for the DVD, about $35 for the VHS tape, plus shipping. Perhaps it is worth the investment for you.
Your father, or you as next of kin, should be able to obtain your father's full service record, which would show the ships to which he was assigned, the applicable dates, and other information, by contacting the U.S. National Archives. See http://www.archives.gov/st-louis/military-personnel/ and http://www.archives.gov/veterans/ for information about obtaining military records.
Ron Carlson, Webmaster
Armed Guard website www.armed-guard.com