Having now also checked the next volume, "Marianne and the Rebels", I think I found the scene I dimly remembered but it's a bit different from what I thought. Marianne and her maid Agathe are kept captive on a sailing vessel in the Mediterranean, by the roguish pirate captain who is infatuated with her. There is a flogging scene, but it's a black male slave being flogged, shortly followed by a crew mutiny in which Marianne gets tied and gagged and abandoned on her own in a rowing boat at sea, and the maid being raped and kept on board for the crew's entertainment -- I must have in my mind combined this with the male flogging shortly before:
As the afternoon drew on to evening, Marianne waited for O'Flaherty with growing impatience. She prowled about her cabin, unable to sit still, and continually asking Agathe what time it was. Still the lieutenant did not come, and when she tried to send her maid for news, she found that this time she was really a prisoner. Her cabin door was locked on the outside. A fresh period of waiting began, a time of nervous fears that grew worse with every hour that passed.
Still the lieutenant did not come. Nerves stretched to breaking point, Marianne could have screamed, banged, clawed, anything to relieve the anger and alarm which threatened to choke her. There was no reason for it that she knew but, like a wild creature, she sensed the approach of some new danger.
What came, at last, when dawn was not very far off, was the sound of the key being turned in the newly-mended lock. John Leighton entered, with a group of seamen at his back amongst whom Marianne recognized Arroyo, carrying a lantern. Contrary to his usual habit, the doctor was armed to the teeth, and an extraordinary expression of triumph, which he seemed unable to hide, shone through his livid countenance, giving it a sinister vitality. Clearly this was the great moment of his life, a moment for which he had been waiting for a long time.
Marianne reacted instantly. Reaching for a wrapper she slid out of bed and faced them.
'Who gave you leave to enter here?' she demanded with dignity. 'Oblige me by getting out at once!'
Ignoring this, Leighton came further into the cabin. The seamen crowded into the doorway, craning their necks eagerly to get a glimpse into the unfamiliar prettiness of the women's cabin.
'I'm desolated to disturb you,' the doctor said, with heavy sarcasm, 'but I fear that it is you who must get out. You must leave this ship at once. A boat awaits you.'
'Leave the ship? In the middle of the night? Are you mad? Where do you expect me to go, may I ask?'
'Where you like. We are in the Mediterranean, not the Atlantic. Land is not far off, and it will soon be dawn. Prepare yourself.'
Marianne folded her arms, hugging her wrap more closely round her, and looked at him, unmoving.
'Fetch the captain,' she said. 'I am not stirring until I hear it from his own lips.'
'Indeed?'
'Yes, indeed! You have no authority, Doctor, which entitles you to give orders on board this ship. Least of all such orders as that.'
Leighton's smile grew, acquiring an added venom.
'I fear,' he said, with horrid smoothness, 'that those are the captain's orders. Unless you wish to be put into the boat by force, you will obey at once. I repeat: make your preparations. Put on a dress, a cloak, what you will, but do it quickly.' He glanced round the cabin. 'You cannot, of course, be permitted to take your trunks, or your jewels. You will not need them at sea and they would only be useless clutter in the boat.'
There was a pause while Marianne digested this astonishing speech. What did it all mean? Was she to be robbed of all her baggage and set adrift on the open sea? It was incredible, horrible and unimaginable, that Jason should have decided suddenly to get rid of her, in the middle of the night, after relieving her of everything she possessed. It was still more inconceivable that he should have chosen Leighton for his messenger. It was so unlike him… it must be so unlike him, surely? Yet even as she asked herself the question, the seeds of doubt were planting themselves in her anguished mind, reminding her of another night, long before, the dreadful night of her wedding to Francis Cranmere, when Jason had left Selton Hall, taking with him every penny of Marianne's fortune.
Seeing that the man before her was showing signs of impatience, she turned her rage on him.
'I thought this vessel was an honest privateer,' she said, with all the scorn at her command. 'I see now that I have fallen among thieves! You are no better than a common pirate, Doctor Leighton, and the worst kind of villain, for you attack defenceless women with force. Well, I'm too weak to oppose you. Pack our things, Agathe. That is, if this gentleman will kindly tell us what we are allowed to take.'
'I did not say,' Leighton countered blandly, 'that you might take your maid. How should you need an abigail in a boat? Any more than you will need your fine dresses? Whereas she may be useful here. You look surprised? Did I omit to tell you that you were to go alone? I must ask your serene highness to forgive me.' Then, with an abrupt change of tone, he added: 'Jump to it, you men. We've wasted too much time already. Take her away!'
'Villain!' Marianne screamed wildly. 'I forbid you to lay hands on me!…Help!…Help!'
But already the men were swarming into the cabin, transforming it in an instant into a miniature hell. Marianne fought bravely, hemmed in by eyes that gleamed like red-hot coals, foul breath that reeked of rum and greedy hands that pawed at her furtively under the guise of dragging her away, but resistance was useless. Yet she redoubled her efforts at the sound of frantic screams from Agathe who was being held down on the bed by two seamen while a third ripped off her nightgown. There was a gleam of plump, white flesh that quickly vanished into the curtained recesses of the bunk, hidden beneath the body of the man who, urged on by his companions, was now energetically raping her.
Meanwhile, although she kicked and scratched with all her might, Marianne was overpowered and with a gag thrust in her mouth to stifle her cries, was manhandled out on to the deck.
'You see,' Leighton told her piously, 'this is what comes of not being sensible. It is your own fault that we have been obliged to use force. Nevertheless I hope you will do me the justice to admit that I have held my men in check. I might easily have let them deal with you as they have with that girl of yours. These good fellows do not love you, Princess. They blame you for changing their captain into a spineless weakling, but they'd be quite willing to enjoy your dainty person, all the same. So thank me properly, instead of spitting like a wild cat. Away with her, you men!'
If sheer blind rage could kill, the doctor would have dropped dead on the spot, or else Marianne herself might well have died. Driven half out of her mind by the sound of Agathe's shrieks, feebler now but still audible, so beside herself with anger as to be scarcely conscious of what was happening to her, Marianne fought with such fury that they had to tie her hands and feet to carry her to the side. There a rope was slung under her armpits and she was lowered with a bump into the open boat bobbing gently on a line from the ship's side. As she made contact with the wooden thwart, uttering an involuntary cry of pain, someone severed the line. The sea carried the boat away at once and, looking up, Marianne saw, far above her, a row of heads gating down. Leighton's voice sounded mockingly in her ears:
'Happy landings, your highness! You'll have no trouble freeing yourself. The ropes are not too tight. And there are oars in the bottom of the boat, if you can row. You need not worry about your friends and servants – I'll take care of them!'
Sick with fury, with a burning head and a sharp pain in her back, Marianne watched the brig sail past her boat, veer gently and then draw away, still hardly able to realize what had happened to her.
Soon, before her wide, tear-drenched eyes, appeared the graceful, brightly-lit stern windows, surmounted by their three lanterns. Then the vessel went about and altered course. Gradually the tall pyramid of sails receded and was lost in the surrounding darkness, until it was nothing but a vague shape marked by tiny twinkling lights.
Only then did Marianne begin to grasp the fact that she was alone on the wide sea, set adrift without food or water, practically without clothes, and doomed, coldly and deliberately, to die unless a miracle occurred.
There was the ship, hull down on the horizon, taking her only friends with it, the ship that belonged to the man she loved and to whom she had sworn to devote her life, and who not so long ago had vowed that he loved her above all else. Yet he had not been able to forgive her for concealing her misery and shame from him.
As it happens, Marianne gets rescued at the last minute by a passing fisherman. No reunion with Agathe in the rest of the book, but the next volume has a short update on her fate:
One person Marianne had not found. Her maid, Agathe Pinsart, was gone—but not very far away, nor was there anything at all tragic about her going. Against all expectation, the poor girl had not only survived the barbarous and inhuman treatment she had suffered at the hands of Leighton and his mutineers aboard the Sea Witch but had made a conquest of the Turkish captain who had captured the brig and released the prisoners with her caustic charms. And since Agathe, on her side, had been greatly impressed by the young reis, with his dashing presence, his silken garments and his splendid mustaches, their voyage to Constantinople had assumed all the appearance of an amorous idyll, culminating in a proposal of marriage from Achmet to his new sweetheart. Agathe, convinced that she had seen the last of Marianne and strongly tempted by the luxurious life of a Turkish lady, had offered only a token resistance designed merely to enhance the value of her consent, and not many days before her mistress's arrival she had embraced both Achmet and Islam with an equal enthusiasm. She was now officially installed in her husband's handsome house at Eyub, not far from the great mosque recently rebuilt by Mahmoud II to shelter the footprint of the Prophet.