A passenger on the boat describes how the Báb and Quddús were “absorbed in their work” together

I have heard Hájí Abu’l-Hasan-i-Shírází, who was travelling in the same vessel as the Báb, describe the circumstances of that memorable voyage: “During the entire period of approximately two months,” he asserted, “from the day we embarked at Búshihr to the day when we landed at Jaddih, the port of Hijáz, whenever by day or night I chanced to meet either the Báb or Quddús, I invariably found them together, both absorbed in their work. The Báb seemed to be dictating, and Quddús was busily engaged in taking down whatever fell from His lips. Even at a time when panic seemed to have seized the passengers of that storm-tossed vessel, they would be seen pursuing their labours with unperturbed confidence and calm. Neither the violence of the elements nor the tumult of the people around them could either ruffle the serenity of their countenance or turn them from their purpose.” 

- Nabil  (Chapter 7, ‘The Dawn-Breakers’)

While on board the boat the Báb dictated to Quddus “such prayers and epistles as He felt inspired to reveal”

High seas and the complete absence of comfort could neither interfere with the regularity of His devotions nor perturb the peacefulness of His meditations and prayers. Oblivious of the storm that raged about Him, and undeterred by the sickness which had seized His fellow-pilgrims, He continued to occupy His time in dictating to Quddús such prayers and epistles as He felt inspired to reveal. 

(Chapter 7, ‘The Dawn-Breakers’)

A sailing vessel

An old-time wooden sailing vessel like this was used by the Báb to sail for Mecca in October of 1844. With Him were the Letter of the Living Quddus and an Ethiopian attendant with a large basket of sweet lemons to make up for the absence of fresh water. The voyage took about two months. They sailed 3,000 miles around Arabia to the Red Sea and to Jaddih, the port of Mecca. 
(source: 'Land of Resplendent Glory', by the International Baha'i Audio-Visual Center, 1971)

The Báb’s uncomfortable sea voyage to Mecca

“He [the Báb] retained the most disagreeable impression of his voyage. ‘Know that the sea voyages are hard. We do not favor them for the faithful; travel by land,’ he wrote in the Kitab-i-Baynu’l-Haramayn in addressing himself to his uncle, as we shall soon see. He elaborates upon this subject also in the Bayán. Do not consider this childish, the feelings which moved the Báb in his horror of the sea are far more noble.

“Struck by the selfishness of the pilgrims which was heightened by the discomforts of a long and dangerous sea voyage, equally shocked by the unclean conditions that the pilgrims were obliged to endure on board, he wished to prevent men from yielding to their lower instincts and treating one another harshly. We know that the Báb especially commended politeness and the most refined courtesy in all social relations. ‘Never sadden anyone, no matter whom, for no matter what,’ he enjoined, and during this voyage he experienced the meanness of man and his brutality when in the presence of difficulties. ‘The saddest thing that I saw on my pilgrimage to Mecca was the constant disputes of the pilgrims between themselves, disputes which took away the moral benefit of the pilgrimage.’ (Bayán, 4:16.) (A. L. M. Nicolas’ “Siyyid ‘Alí-Muhammad dit le Báb,” pp. 207–208.) 

(Footnotes to chapter 7 provided by Shoghi Effendi)

A drawing of Mecca

The Báb left Shiraz for Mecca and Medina in October 1844

According to Hájí Mu’inu’s-Saltanih’s narrative (p. 72), the Báb set out on His pilgrimage to Mecca and Medina in the month of Shavval, 1260 A.H. (Oct., 1844 A.D.). 

(Footnotes to chapter 7 provided by Shoghi Effendi)

The Báb started His pilgrimage to Mecca and Medina

The letter of Mullá Husayn decided the Báb to undertake His contemplated pilgrimage to Hijáz. Entrusting His wife to His mother, and committing them both to the care and protection of His maternal uncle, He joined the company of the pilgrims of Fárs who were preparing to leave Shíráz for Mecca and Medina. Quddús was His only companion, and the Ethiopian servant His personal attendant. He first proceeded to Búshihr, the seat of His uncle’s business, where in former days He, in close association with him, had lived the life of a humble merchant. Having there completed the preliminary arrangements for His long and arduous voyage, He embarked on a sailing vessel, which, after two months of slow, stormy, and unsteady sailing, landed Him upon the shores of that sacred land. 

(Chapter 7, ‘The Dawn-Breakers’)

circa 1935: Views of the mosque of Gawhar-Shad in Mashhad showing pulpit where Mulla Husayn preached

(The Dawn-Breakers)