Present tense, the tensest tense.
Moving across the wide expanse of ocean water, a large sailing yacht gleams in the clear sun lit day.
An interesting pivot. Makes me want to know more about the local culture and economy.
The blood connection meant that it was quite likely that as adults the cousins were occasionally going to be required to share a boat.
This passage would be more effective as monologue from Dad, maybe with Trivian only reluctantly listening, since he’s heard the story before.
The night of their births was legendary in the village.
You mean "previously". "Hence" is in the future.
“Playing marbles? What with, badgers?”