"I must go down to the seas again, to the lonely sea and the sky,
And all I ask is a tall ship and a star to steer her by,
And the wheel’s kick and the wind’s song and the white sail’s shaking,
And a grey mist on the sea’s face, and a grey dawn breaking.”
In 1874 he captained the Sir Galagad to South Africa and back. His longest time at sea was in 1862 when he was away from home for one and a half years and his shortest was just over two months. After his marriage, you can date the conception of his children exactly with the time he was at home.