There is a rule we learned years ago working on fishing vessels: no saving exists until it has been measured.
Industrial fishing operators have lived with fuel opacity for a generation. Tank dips at the start and end of a trip, divided by the days at sea, averaged across a season — that's the historical baseline for most fleets. It is not accurate enough to detect a 5% improvement, and a 5% improvement is exactly what separates a good fuel-saving product from a marketing claim.
Why Tank Dips Fail
Tanks roll, list and change temperature. Fuel density varies with source. Return flows to the tank aren't captured. What the engine actually burned is a derived number with enough error bars to swallow the thing you're trying to measure.
What a Mass-Flow Meter Gives You
A marine-grade mass-flow meter sits on the supply line (and, done properly, the return line) and reports the true net mass of fuel consumed. Paired with engine load and RPM, you get specific fuel consumption — grams of fuel per kWh of shaft power — for every moment of every trip. Suddenly the conversation changes. Captains compare against each other. Engineers see the cost of a dirty injector in real numbers. Owners can tell whether a saving device actually did anything.
The Installation Sequence That Matters
Fit the meter first. Run a full season, or at least enough trips to get a stable baseline across weather and catch types. Fit the saving device. Keep the meter in place. Compare — same vessel, same crew, same route, measured delta. Most fuel-saving products die on step one because they never had a real baseline. The good ones survive because the data makes the case for them.
Why We're Still in the Water
We manufacture the hydrogen fuel-saving units ourselves, and we specify and install the meters from qualified OEMs. We do both because we learned early that one without the other is a sales argument, not a result. The solar EPC business has this lesson baked into it too. Commissioning a plant means measuring the performance ratio before anyone signs the handover. The principle travels.