anchored at Avalon, Santa Catalina Island, in May 2000
MV Conception was a 75-foot (23 m) liveaboard boat built in Long Beach, California, and launched in 1981. It was one of three dive boats owned by Truth Aquatics, which operates charter excursions from Santa Barbara Harbor for groups of divers interested in exploring the Channel Islands, located close to the coast of Southern California by Los Angeles and Santa Barbara. Conception was under charter to Worldwide Diving Adventures (WDA) for a three-day scuba diving excursion over the Labor Day holiday weekend, which was one of WDA's most popular diving tour packages. The boat had been refurbished at a cost of more than $1 million following an incident in 2005 when it had been stolen and run aground.
Federal and international regulations require boats over a certain size to be made of fire resistant materials and to include fire sprinklers and smoke detectors wired into the ship's electronics or linked to the bridge. Given the vessel's age and size, Conception, at less than 100 GT and with fewer than 49 berths, was not covered by those regulations. It was constructed of wood covered with fiberglass, as permitted by regulations last updated in 1978. At the time of the fire, Conception was believed to be in compliance with those regulations, and the most recent Coast Guard inspections in February 2019 and August 2018 did not result in any noteworthy violations. According to the vessel's Certificate of Inspection, it had a maximum capacity of 103: 4 crew and 99 passengers; one crewmember was required to be designated as a roving patrol at all times when the passenger bunks were occupied.
lower deck bunk room, starboard side facing aft, from a May 2003 dive trip
The boat was laid out with three decks. The upper sun deck contained the wheelhouse. The main deck, just below the sun deck, included a large cabin, which had a galley (in the forward portion of the cabin) where the crew could prepare meals and a salon (in the aft portion) with seating for meals. On the lower deck, up to 46 individuals could sleep in 13 double bunks (12 of which were stacked in twos) and 20 single bunks (18 stacked in threes), with one labeled as reserved for crew. The rest of the crew berths were located two decks above, in the aft portion of the wheelhouse on the sun deck.
According to the deck plans, the main access to the guest accommodations was the forward stairway connected to the galley and main deck cabin. The designer of the vessel stated that there were two exits from the bunk room: a forward staircase at the bow end of the vessel that led up to the galley area, and an aft escape hatch located above one of the bunks, which led to the salon. After exiting the aft escape hatch, a person would still be within the main deck cabin, approximately 3 to 4 feet (0.91 to 1.22 m) forward of the exit to the main deck. Some former dive passengers could only recall the forward stairway exit and could not recall if they had been briefed on the presence of the aft emergency escape hatch. Santa Barbara County Sheriff Bill Brown stated both exits appeared to have been blocked by fire during the disaster.