This is likely to be Chemical Plant by Ian Williamson (appears in "New Worlds, #8 Winter 1950").
A spaceship has to land on a planet and mysteriously disappears. A rescue ship arrives but initially finds nothing.
The Internet delivers this text:
A night of worrying produced no result. It did not occur to him to consult his officers; without consciously expressing the thought, he felt that as commander he was automatically the person most fitted to solve the problem. A cold shower and a well-served breakfast refreshed him immensely, and he took pencil and paper with the determination to settle this business. He wrote down the substance of his information after the manner of a Euclidean demonstration:
I. The Persephone, a Mark IX light cruiser of 8,000 tons, lands beside an obviously artificial watercourse with no engines and only enough reserve energy to transmit one distress signal.
II. Within twenty hours the Persephone has vanished and there is no trace of any struggle, or of any machinery used to move her, except a small raised patch of
vegetation on the spot where she presumably landed. (He was not above using Britt’s information.)
III. Obviously, therefore, she was moved by air, and the patch of vegetation was a hasty attempt to conceal the spot where she crushed the vegetation.
IV. It follows that we are confronted by a hostile and organised intelligence of some mechanical ability.
V. Standing Orders, Section XVI, Chap. 473, Para. 28673 expressly forbids any attempt by less than three vessels to intervene in such a case, but to call upon
nearest Sector Force.
This seemed to be watertight enough, but an attempt at a more detailed explanation would look better, in view of Britthouse’s efforts, blast him. Why had the Persephone been kidnapped?
While some are gearing up to nuke possibly hostile aliens, it eventually dawns on the Persephone's captain that the local plant life is looking for refreshing metals, uses acidic lakes for digestion and hasn't passed on this great occasion:
Five minutes later the faithful Sergeant reported at the control-room with a very troubled face. “I’m sorry, captain,” he said, “but I’m afraid the ‘Jen—’ the runabout is unserviceable.”
“Corrosion, sir. The tracks are heavily corroded and the bearings have developed so much slack that they won’t track properly.”
“But that metal is practically incorrodible.”
“I know, sir, that’s why I wasn’t sure the first day. But the juice that got into them yesterday has made ’em much worse.”
“Juice? What juice?”
“The juice—the sap of these plants, sir. The tracks have been running in it for two days. That is what has corroded them, sir.”
“Holy Smoke!” cried Britt, “Of all the double-distilled fools!”
“T’m sorry, sir,” said the sergeant stiffly. “I didn’t think it—”
“Not you, sergeant,” cried Britt, “I’m the fool. O.K. Now we've got to move. We may just get them out before that dimwit Japp starts up his heaters. Gimme that control-board, Mike, this has to be quick.”
“You know where the Persephone is?” demanded the startled navigator.
“Sure,” said Britt, grinning broadly, “at the bottom of the red lake.”
This gives us a final bon mot:
“Good job we drained the lake in time,” said Bob.
“They were in no danger from the plant,” replied Britt, “they would have reserve air and food for weeks. I suppose the hatches must have jammed so they couldn't get out. Anyhow, all they had to do was to wait till the plant released ’em by dissolving away the hull, then float ashore in their space-suits. Their danger was from that damned Greek, Japp. The Fleet’s heavy heaters would have boiled them alive in ten minutes.”
“Greek?” said Michelson, “is he Greek, then?”
“Oh, don’t you know?” chuckled Britt, “Listen, There was once a party of Greek thinkers — this was around the time of Aristotle — who sat up all night having a furious argument about the number of teeth in a horse’s mouth. Unable to agree, they went out and collared a passer-by — an Arab, it happened to be — and persuaded him to arbitrate. He listened attentively to all their arguments, and then without saying a word he walked away. He returned in a few moments, however, and told them the correct answer. ‘How did you decide?’ they cried. ‘Whose was the better argument, the sounder logic?’ ‘Logic be damned,’ he says, ‘I’ve just been round the back to the stable and counted ’em.”