The pilot of the Ariel yacht states in his log that he is in the lead in a round the world race. He also mentions being 206 days out from Plymouth and having his last radio contact with Melbourne. "Plymouth" is probably a reference to the city in Devon county, England. "Melbourne" is probably a reference to the city in Australia, supported by the opening third-person narrative box that the boat is in the South Pacific and, on page 2, panel 10 of the story, the alien points to the Great Barrier Reef on a chart, indicating to the yachtsman he wants to head in that direction; the Great Barrier Reef is off the coast of Queensland, Australia.

The overhead view of the yacht shows it to be a trimaran, having a main hull and two parallel minor hulls, placed on either side of the main. Trimarans are often used for racing.

On page 2 of the story, Straker remarks that they know the aliens can survive in a liquid environment and even below the surface of the ocean. These are references to the aliens' life support suits, which are filled with a breathable green fluid in the helmets for space travel (evidenced since the first episode, "Identified"), and, likely, Straker's own underwater adventure in which he and Foster discovered a submerged alien structure in "Reflections in the Water".

On page 2, panel 8 of the story, the alien uses a previously unseen type of pistol that fires a laser beam or electronic discharge.

The recap paragraph of part two of the story states the yachtsman's name is Robin Jackman, though he never states it in the story. Yet, somehow, Carlin knows Jackman's name on page 5 of the story!

On page 4 of the story, Carlin refers to Jackman's yacht as a cockleshell. A cockleshell is a nautical term for a small, lightweight boat.

Jackman runs up a series of nautical flags that Skydiver decodes into meaning, "Danger...keep away...plague on board", realizing that Jackman must be a captive of the alien. But the flags shown do not conform to any actual nautical signal flags!

This story reveals the aliens have a device capable of disabling all electronic components in a wide region. Possibly it projects an electromagnetic pulse (EMP), which is known in the real world to have similar effects, though the effects seen in this story go away once the device is shut off. Colonel Freeman later refers to it as "some kind of alien negative force field."

On page 7, panel 4 of the story, Jackman calls the aliens "green-faced gannets". A gannet is a type of large sea bird known for eating large amounts of fish. The word "gannet" has come to be used as a descriptive term similar to "glutton", though its use here does not really fit the aliens.

The patrol plane sent to investigate the loss of contact with the north-eastern coast of Australia is a SHADair Albatross, also seen in several other UFO stories, both televised and in print.

On page 10 of the story, the aliens have captured the Skydiver crew (except for Carlin) and contained them in capsules. But where did the capsules come from? The aliens appeared to be empty-handed when they walked across the underwater reef on page 9!

On page 11 of the story, Straker arrives in Adelaide. Adelaide is the capitol of the state of South Australia.

With essentially all vehicles disabled in eastern Australia, Straker sets off with three other SHADO operatives on camelback from Adelaide, heading for Brisbane. But Brisbane is well over 1,000 miles away from Adelaide! Yes, they are hoping to catch a steam train on the way, if the engineers are able to get them running in Adelaide, by riding alongside the railway, but they'd be better off just waiting until they are running than expecting to get anywhere in a reasonable time on camelback!

On page 12 of the story, Carlin is helped by a band of aboriginal Australians on the Queensland coast. Queensland has the second highest population of aborigines in Australia, after the Northern Territory.

The aborigine called Albert has a very large war boomerang with him which he uses to take down the power source in the aliens' underwater base. But it did not seem that the aboriginal village was nearby, so why was Albert carrying a war boomerang with him?! Regular boomerangs for hunting maybe, but not a giant war one!

At the end of the story, Albert claims (possibly jokingly) he is going back on walkabout. The term "walkabout" refers to an aboriginal rite-of-passage journey across the land, usually by adolescents, as part of growing into an adult. Additionally, adults may also go on walkabouts as a spiritual journey or break from normal life. 

Jackman uses a number of unlikely nautical-themed exclamations: "What in the name of Neptune..?", "Suffering sea-snakes!", and "Great sufferin' sea serpents!"  

UNANSWERED QUESTIONS

Will SHADO use the amnesia drug on Jackman and the aborigines to make them forget their encounter with aliens? It seems like the aboriginals might be hard to track down again!