By Water 2: Uncharted Lands

The crew of the "Syarduyar Arhilka" travel south, past contrary currents, giant waterspouts and barren, poisonous lands.
Finally reaching an island of plenty, they encounter huge and aggressive serpents, one of which kills a member of the crew.
Many more are discovered elsewhere on the island.
A storm drives the ship further south to an island with enigmatic objects and inhabitants who have lived in isolation for over a thousand years, pursuing the "Way of Ttavmasi" (a version of Buddhism). The crew remain there for a while to learn and recuperate, while Rakvir Stagarnik and his grandson, Kaarvi, ponder the events of the journey (including an encounter with a huge sea-monster) and what it suggests about the nature of their world.
The second volume in the epic "By Water" is set in a distant planet, not too dissimilar from our own, written by Richard Hernaman Allen, a former Commissioner of Customs & Excise, as a follow-up to "Through Fire".