Final answer:
Percy, Annabeth, and Tyson board a modest ship humorously compared to a station wagon by Percy. This is contrasted with the Athenian triremes, representing military might.
Step-by-step explanation:
The boat that Percy, Annabeth, and Tyson board in the context provided is referred to as an old junk by Percy himself, which he humorously compares to a station wagon. This indicates a modest, possibly decrepit ship that's being used as a means of transportation by the characters.
In contrast, the Athenian triemes mentioned in the historical reference represent a significant advancement in naval technology, marking the transformation of Athens into a naval power. This juxtaposition of the old junk with the Athenian triremes highlights the different ways in which ships can be perceived and utilized, whether for humble travel or grand military strategy.