Field guide
01Treat travel as a progression problem
Quests and bosses unlock new islands in the official game loop, so boat upgrades only become useful when a route exists to travel. The Radar and coordinates are part of that handoff between one island and the next. A faster boat cannot replace an unfinished quest, a missing bait item or an unreturned boss trophy.
This makes timing more important than a universal “buy immediately” rule. If the crew is still blocked by the active encounter, put enough resources into that encounter first. Once an NPC has given new coordinates, travel becomes a concrete problem an engine purchase can address.
02Do not sacrifice the current boss plan
Early choices are a trade-off between combat preparation and boat progress. A boss that has not been cleared still prevents the next island from opening, even if the boat can move faster. Keep a dependable weapon, recovery supplies and the required bait before spending the same money on travel convenience.
This is not an argument against boat upgrades. It is an order-of-operations rule: clear the reason to leave, then invest in getting there efficiently. In co-op, agree on that decision as a group so one player’s travel purchase does not consume the resources another player needs for the quest.
03Use the navigation cue after every hand-in
The Spider Crab shell, Giant Piranha Skeleton and Pufferfish Tail routes all end with a quest return before the next destination appears. After each completed hand-in, check the game’s updated navigation information before setting out. That avoids sailing around with an engine upgrade while the actual coordinate interaction is still incomplete.
A missing route should trigger a hand-in check, not an automatic second boss fight or a new engine purchase. Confirm the distinct trophy was collected, the right NPC accepted it and the current objective changed. Only then evaluate whether travel speed is the next friction point.
04Avoid unverified engine tables
Engine upgrades exist, but a reliable complete table of engine names, speed changes, requirements and version history is not available. This page therefore avoids publishing a definitive tier chart. A table that looks precise without a stable record would be less useful than this decision guide.
Use the live shop for the current price and compare it with the resources still needed for the next quest. Confirm an individual engine value against the current build before adding it to the wiki. That makes the page correctable when balancing changes rather than permanently tied to one early guide.
05Keep the boundary visible
The current route shows when travel becomes important, not every outcome of every engine purchase. It does not prove a fixed speed increase, an exact best engine for all routes or an optimal solo-versus-co-op economy. Those claims remain out of scope until repeatable tests are available.
For a practical next action, finish the active quest, collect and hand in its distinct trophy, confirm the new coordinates and then buy the travel improvement that fits the new leg. This is a clear, answer-first route without pretending the wiki owns an authoritative engine database it does not yet have. It also gives a player a visible in-game check before committing more currency.