What are the two voyages described by the narrator in chapter 1 of Three Men in a Boat?

When he and his friends are pondering a holiday, the narrator decides he doesn't want to go on a sea journey. He tells the story of his brother-in-law who, to improve his health, decided to take a short trip by sea. He booked a return (round trip) ticket from London to Liverpool, but the trip to Liverpool was so terrible he returned to London by train. He sold his return ticket but could only get a very low price for it—as nobody wanted to travel by sea.
The narrator also tells of a friend taking a sea journey who was advised to save money by paying for all his meals ahead of time. In reality, he was so often seasick that he lost money on the deal. As the narrator explains:

For the next four days he lived a simple and blameless life on thin captain's biscuits (I mean that the biscuits were thin, not the captain) and soda-water; but, towards Saturday, he got uppish, and went in for weak tea and dry toast, and on Monday he was gorging himself on chicken broth. He left the ship on Tuesday, and as it steamed away from the landing-stage he gazed after it regretfully.
"There she goes," he said, "there she goes, with two pounds' worth of food on board that belongs to me, and that I haven't had."

Because of their worry about ocean voyages, the three friends decide to take a boat trip down a river.