Although my work-in-progress, the seventh Mora novel (to be titled Warrior of the Moon), is a fantasy set in another world it returns to the premise of the very first in the series (Coast of Spears), that is people from our world passing through a ‘gate’ to another. It is set some twenty-two years after the first story (in 1936) so the technology has changed some. Lots of small things are different, of course, weapons and such. These are details that can be dropped in when appropriate, or ignored if not important to the plot.
What is important are the means of transportation that got them there. As our portal is located in the South Pacific, this means boat or airplane. Malvern and his fellows from the first books came through on a fairly large private yacht sailing from Panama (the Canal had just opened) to Tahiti. Before their time, canoes or rafts of varying sorts had brought through Polynesians, Proto-Malays, Australian Aborginals, etc. for millennia.
My first concern was Lady Lydia Viney, an Amelia Earhart want-to-be who takes it into her head to fly across the Pacific solo. For this journey she chooses a Fairchild Eighty-two single-engine float plane, modified for extra range. This is in part her choice because it is Canadian-made; Lady Lydia would rather not use something from America or Germany, and found nothing quite satisfactory made in Great Britain. Attempting such a crossing in such a machine is entirely plausible, even if a bit foolhardy. Of course, she was hopping from island to island, not flying nonstop. So I am good with that choice.
Then there is the more complicated subject of the Japanese submarine that comes through — the last visitor ever, most likely, as part of the plot concerns the blocking of the gate. One concern here is that the fate of most ships in the Japanese submarine fleet is known. How to get around that?
I have chosen to make it a vessel of the Kaichu class, a medium-sized submarine, and an older one, possibly built as early as World War One or shortly thereafter. I did toy with the idea of making it one of the German subs received as repatriations at the close of the war but decided against (though probably only I will know this — there is no need to go into any of its history in the story). Officially, this submarine will have been decommissioned and broken up; in fact, it has been secretly refitted for long-range spy missions. That is why it is cruising the South Pacific at that time. The Japanese military got wind of the research in Soviet Russia at the other gate located there (and also closed now — that happened in my non-Mora novel, Tsar of the Empty Lands) and are carrying out investigations of their own.
So I can have my submarine. To be sure, I needed (and may still need) to research it thoroughly even though the vessel itself does not play a big role (I think. Things could always change.) Perhaps some of this research can pay off in other books yet to be written. It definitely gave me some ideas to explore that might pop up in a future Wilk (non-fantasy adventures) novel. We’ll see about that.