McCullough’s The Path Between the Seas: “Channel lighting was installed in 1966 and night-time transits were inaugurated.”
Encyclopedia Britannica 14th Edition (late 1930s): " A thorough system of lights and buoys makes the canal as safe to use at night as by day."
McCullough’s book says a trip thru the canal’s fresh water kills all the barnacles on each ship. The world’s ships are covered with dead barnacles? Which still stick?
Can’t comment on the canal part, but can confirm that dead barnacles do stay stuck to boat hulls long after the organism is dead. The bond is like glue or epoxy - once established, it’s not coming off until you physically knock it off (with a scraper, sander, etc). They’re not attached with say an octopus-like suction cup that releases when a muscle relaxes.
Yes, that’s a well-known necessary maintenance procedure.
During WWI, a German cruiser pulled into the British base at Diego Garcia and had her hull scraped and repainted - because the British personnel at Diego Garcia hadn’t gotten the word that there was a war going on.
During the first two weeks of October the Emden was rumored to be in the Makassar Strait, east of Borneo, at Padang on the Straits of Malakka and southeast of Sumatra, but in reality she seems to have been far away at Diego Garcia in the Chagos Archipelago. There she cleaned her boilers, was heeled over and had her bottom scraped and painted as far as practicable
The 14th edition of the Britannica was begun in the 1920s and published in one go in 1929, but after that release, the editors moved to a continuous revision model that saw new edits being made for decades afterwards; it wasn’t until the 1970s that a complete overhaul came out in the form of the 15th edition. The self-referential article in the Britannica about the history of the Britannica explains this in detail: https://www.britannica.com/topic/Encyclopaedia-Britannica-English-language-reference-work/Fourteenth-edition
So it might well be that that passage you’re citing from the 14th edition dates to after 1966, which would remove the discrepancy between the encyclopaedia and McCullough’s standard book.
On any day, ships entered the canal in the early morning,6 to 9am , with the intent to exit afternoon or early evening, because its the 10 - 14 hour journey , but of course some exited late evening, 11 pm
Even ships that had arrived at an entry port midday waited to the next morning to enter, in 1926.