When you're comparing marine electronics sonar navigation gear, the first decision is about the job at hand. Do you need to know where you are going, or do you need to know what's below the boat? These two units point in different directions. The Boat GPS Navigator 5in is a full navigation screen with a price tag near the top of this two-product window. The Garmin Fishfinder Depth Finder 80 is a much smaller investment aimed at fishing. With roughly a $272 spread between them, the choice comes down to how much of your time on the water is spent navigating versus fishing.
Quick verdict: Choose the Boat GPS Navigator 5in when route planning is the priority. Choose the Garmin Fishfinder Depth Finder 80 when you want an inexpensive fish-finding tool and can accept a used unit.
At a glance
| Product | Listed price | Price bar | What stands out |
| Boat GPS Navigator 5in Marine GPS Navigator AIS TFT LCD Screen LED Backlight | $336.52 | | 5-inch TFT LCD with LED backlight, dual chart system |
| Garmin Fishfinder Depth Finder 80 Marine Boat Sonar | $65.00 | | Sonar sensors, Decimal & Imperial measurement |
Where each wins: The Boat GPS Navigator 5in wins for navigation. It combines location, heading, and route tools in one unit, making it the stronger choice when navigation is your main task. The Garmin Fishfinder Depth Finder 80 wins for fishing value. It focuses on depth and fishing, and its price is dramatically easier on the wallet, so you get a workable fishfinder without committing a large chunk of the budget.
Boat GPS Navigator 5in Marine GPS Navigator AIS TFT LCD Screen LED Backlight
The Boat GPS Navigator 5in delivers the core navigation package: a 480 x 272 TFT screen with LED backlight, wide voltage DC12-36V input, compass/GPS dual-mode positioning, six screen modes, and support for multiple languages. The built-in map options are a standout for boaters who switch between different areas. The screen is the main interface, and the unit also gives you position, speed, and heading in one place. The limitation is cost: at more than five times the fishfinder's price, it only makes sense if you'll actually put the navigation tools to regular use.
Garmin Fishfinder Depth Finder 80 Marine Boat Sonar
The Garmin Fishfinder Depth Finder 80 is the budget pick at $65.00. Its sonar sensors focus on finding depth and marking fish, and the plastic housing is a practical choice for marine use. It also handles both Decimal and Imperial measurement, so it works with the units you already use. The main trade-off is condition: this is a used unit, so you're accepting that status for the lower price. If your goal is depth and bottom information while fishing, this is the more sensible buy. When you need the navigation features of the GPS unit, the Boat GPS Navigator 5in covers that side of the matchup instead.
Final choice by use case:
- Open-water cruising and route planning: Boat GPS Navigator 5in.
- Small-boat fishing and fish-finding on a budget: Garmin Fishfinder Depth Finder 80.
- If you want the fuller navigation package and can stretch the budget: Boat GPS Navigator 5in.
- If you want a low-cost fishfinder that gets the basics right: Garmin Fishfinder Depth Finder 80.
