Here are translations of the previously posted two Demenkov's articles (reply 231). First one is not complete, because it's not exactly about IF. Just excerpt where Maria is mentioned. Second one is complete.
1. "Senior Lieutenant N. D. Demenkov, Paris. 1934.
When I served in the HIM Guard's United Infantry Regiment I had many times the good fortune to receive invitations to play tennis with Their Imperial Highnesses the Grand Duchesses, and Emperor himself often watched the game. We played tennis usually in special sports clothes, the same example of which, as I remember, was approved on the highest level for officers of the Guard, Army and Navy shortly before the start of war.
In early July of 1914 (The Imperial family was staying at Peterhof) during one of the games button has come off from the collar of the shirt of my sports costume, which immediately became sloppy. There was no pin near my hand. Her Highness Grand Duchess Maria Nicholaevna, seeing my involuntary embarrassment, with the usual for the whole Imperial family charming simplicity came to me and offered to use her scarf, which, as I remember was white with a blue border and matched with a that day's white-blue dresses of Their Highnesses. Tied this white-blue scarf around my neck in a bow, Her Highness immediately drew Emperor's attention on this scene, at that His Majesty smiled and noted that these are the "marine colours"..."
2. "Senior Lieutenant N. D. Demenkov, Paris. 1938.
Conspiracy with the Tsesarevich
From July till December of 1913, the 3rd Division of destroyers of the Black Sea Mine Division under the leadership of the 1st Rank Captain Duke V. V. Trubetskoy, held the honorable service of Livadia Naval guarding, where the Imperial family stayed. In those happy days I sailed in this Division as a flag-Officer of the Duke. Strong and sometimes hot-tempered nature of the Duke has always impressed those who didn't know him and it's warm heart, the impression which is usually called "angry". "Angry Duke" - of course jokingly, but was also a nickname of Trubetskoy amoung the Imperial family members.
At all the time of our Division stay in the Naval guarding, three steam boats armed with machine guns from the battleships "Saint Eustace" and "John Chrysostom" and from the cruiser "Cahul" were attached. These three boats carried the daily active service one after another. Managing and monitoring of the right service of these boats, by the Duke's order, were entrusted to me. If the agreed signal from Standart appeared, then immediately the guard-boat went out to sea and according to special instructions was required to monitor carefully the water space, during the Emperor's bathing or kayaking. At the time of this monitoring it was forbidden to show that these actions are done in order of protection and even generally it was forbidden to restrict the movements of the Emperor. In the case of any serious danger, the boat was supposed to let the know about this with agreed signal to a current duty destroyer, which was on a standing in the Yalta port in full combat readiness. In order to check the boat serviceability, every morning I had to go out to sea after the flag lifting on another boat entering the service.
Once, in one of the lovely days of September, returning on the "Eustace" battleship's boat from that kind of "trial run", we noticed conventional signal elevated on Standard, signifying an order to go immediately for the protection of the Livadia shore. I delayed the process of agreed changing of service watch and we rushed at full speed to our destination. It's need to say here, that on boat entering the service - during the changing - a set of braid pendants of the Highest Persons were passed among the other things, in case if someone of them will use the boat. Unwittingly I had to stay on the boat, not yet entered into service watch, but because of the signal already performing it's original purpose. All the "sweetness" of prospect of "another one scolding" for being late to my "angry" Duke's report already imagined in my Midshipman's head.
We've saw a ship's boat near the Imperial bathing, in which, as I could seen in binoculars, were Tsesarevich and all the four Grand Duchesses. Tsesarevich with his "uncle", bosun Derevenko, was sitting at the wheel, while the Grand Duchesses at the oars. Special signs were given to us from the boat. Assuming that something dangerous has happened, I ordered a turn to the boat and give the most complete course. Coming closer I saw the smiling, ruddy faces of the "High" rowers, now I was convinced that all is OK and nothing is dangerous, and that's why, following the instructions I began turning to retreat seaward, when suddenly from the boat I heard a loud voice: "Here!"...To us!...come closer!..." We have fulfilled the order and approached the boat. Grand Duchess asked me with a little embarrassment: "Is it possible to take a ride on a boat?" We, of course, were happy to help all to change their seats from boat to our cutter and finally gave the full speed.
Calm sea and bright sun favored our boating. The first involuntary embarrassment was gone away, and soon the atmosphere of touching simplicity created in our little ship. Grand Duchesses without any embarrassment talked with me and with all the boat's servants. Inherent delicacy of the Grand Duchesses obviously helped them to inquire whether they detain me or not. They knew that every morning I was supposed to be on a Commander's of Division report. - "And what if you will catch it from the Duke, because you didn't came to the report?"...He's angry!" I answered that from this side there is no danger, since I'm on active service, but honestly said that I can get hot because of our boat which does not have a special braid pennant of Tsesarevich, which was supposed to be hoisted right now on the nose flag-stock. At the same time, the expression on my face and tone of voice, perhaps, betrayed my anxiety, as Tsesarevich immediately reassured me: "Do not worry, I'll tell the Duke that I ordered not to hoist a braid pennant" - he said, and then with the powerful and very serious tone turn to his sisters and told: "And you - be silent!"
Tsesarevich kept his word and at the first meeting with Duke Trubetskoy told him about the "order". So, with a charming and adorable child - an idol for the whole Russia - our young 9-years old Tsesarevich, who was totally filled with my state of mind and wish to help me out of trouble, I made plans to deceive my angry boss.
We sailed on a boat for about an hour. Tsesarevich was giving orders to the helmsman, including changing the courses and even reported to the engine room about the speed changes. Grand Duchesses, thanking us, changed back their seats from our cutter to the boat and gave me and servants a few candies, in order to eat them "after forthcoming dinner".
Fascinated by such a sincere and friendly simplicity of the Emperor's children in communication with us, - in the good mood we returned to port. These memories about our little journey I'll keep in my heart - and I believe - that all the boat's servants - till the end of their days. I do not think it's necessary to add that the candies of cause were not eaten, but have carefully kept as a souvenir."