Two days two heart attacks!!
On the nineteenth, August, 1965, when the ship arrived at Colombo, Ceylon (now Sri Lanka), Bhaktivedanta Swami was able to get relief from his seasickness. The captain took him ashore, and he traveled around Colombo by car. Then the ship went on toward Cochin, on the west coast of India. Janmastami, the appearance day of Lord Krishna, fell on the twentieth of August that year. Bhaktivedanta Swami took the opportunity to speak to the crew about the philosophy of Lord Krishna, and he distributed prasadam he had cooked himself.
August 21 was his seventieth birthday, observed (without ceremony) at sea. That same day the ship arrived at Cochin, and Bhaktivedanta Swami's trunks of Srimad-Bhagavatam volumes, which had been shipped from Mumbai, were loaded on board.
By the twenty-third the ship had put out to the Red Sea, where Bhaktivedanta Swami encountered great difficulty. He noted in his diary, "Rain, seasickness, dizziness, headache, no appetite, vomiting." The symptoms persisted, but it was more than seasickness. The pains in his chest made him think he would die at any moment. In two days he suffered two heart attacks. He tolerated the difficulty, meditating on the purpose of his mission, but after two days of such violent attacks he thought that if another were to come he would certainly not survive.
Reference: Excerpts from Acharya book with illustration by Bhaktisiddhanta Dasa