EDIT: reworked the water reflection.
Another Shadowless reference drawing, of French submarine Gustave Zédé and canal boat Belle Lurette, both vessels that will feature heavily in the first volume.
In real life Gustave Zédé was one of the earliest commissioned naval submarines, launched in June 1893. Unlike more modern submarines, she was exclusively electric, running off batteries and without any onboard means to recharge them, which gave her a range of only around 220 nautical miles (410km) at a speed of either 9 knots (17 km/h) surfaced of 6.5 knots (12 km/h) submerged.
Also unlike more modern submarines, she was made almost entirely out of bronze rather than steel to resist "aqueous corrosion" (electrochemical corrosion of steel due to seawater being a superb electrolyte), which also allowed a magnetic compass to operate inside.
At 45 meters long and 264 tons surfaced (274 t submerged), Gustave Zédé was also much larger than any other contemporary submarines (in fact the earlier Gymnote, from which it was derived, was only 17m long and weighed 30 tons surfaced), and also quite well armed, equipped with a 360mm internal torpedo tube and two external torpedo launchers. In real life she did two successful submerged torpedo practice attacks on the battleship Magenta in 1899 in the presence of the French Minister of the Navy and invited journalists, which spurred the further development of the submarine as a weapon of war.
Since she was an experimental design, she went through a lot of iterations as they tried different equipment, but I have drawn the submarine as she appeared around 1900.
Belle Lurette, (which is a French phrase meaning "for a long time", a reference to the fact floating around the canals of France does take quite a lot of time) is a special type of canal boat called a "chaland de Rance", a boat endemic to the north of Brittany and which is able to sail on both the sea in the Rance estuary and the "Canal d'Ille et Rance" and by it's connection to the Vilaine river in Rennes is able to traverse Brittany north to south from Saint Malo all the way to the Bay of Biscay.
Because she has to negotiate the locks of the various inland waterways, her dimensions are fixed to 26.5m in length, 4.5 meters on the beam, a draft of 1.6m and a total height of 2.5m in order to pass under bridges. For this the masts also fold down along the top of the hold covers.
In terms of propulsion, each mast carries a single lug sail (itself the traditional type of sail used by Breton fishermen on their boats) while on the rivers and canals she is towed along by either animals or, since the start of the war and the fact most horses have been confiscated for use by the army, by her own crew.