Comparison

First Mate vs GrowDiary

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

First Mate

Features
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First Mate is the app every boat owner needs for a reliable and enjoyable boating excursion. First Mate is the first app using advanced Naval Architecture and Marine Engineering calculations and tow tank test data to provide you with vessel duration, range, and engine output without the need for expensive integrated management systems. This app compliments your navigation equipment and gauges to calculate the information needed to plan or update the journey in real time. Input the fuel and vessel speed; First Mate will calculate:  • Hours to empty • Distance to empty • Estimated engine RPM, fuel burn rate, brake horsepower All calculations update when user updates the app. Typically trip planning is done using rough estimates using data from the vessel manufacturer. Integrated management systems can cost hundreds or thousands of dollars, require installation, and only provide basic information about engine performance and maintenance. First Mate is a robust app that accounts for drag, weight, and engine performance to accurately plan excursions and spontaneously change plans while underway. The user interface is designed to allow anyone, regardless of boating knowledge, to easily set up and use the app. Because this app covers all planing monohulls, information about the vessel must be input under the “Vessel” tab. Information about the vessel is available at the manufacturer’s website. It is very simple to use for beginner or advance users. Once the Vessel tab is filled out, print it as a backup and keep a copy in the vessel log book. The “Dashboard” tab provides the user with all the information to estimate range based on the speed, weight, and current fuel readings. Other important information is displayed on this tab includes: engine RPM, fuel burn rate, and brake horsepower (BHP). The environmental input is used to calculate the seastate and the effect it will have on the range. Departure fluid levels and weights are used to estimate the total vessels displacement. There are several reference tables on the “Tables” tab to help estimate the remaining fluid levels based on gauge readings and seastate based on Beaufort Wind Scale. The app can be updated when the engine or propeller is upgraded without the need to buy anything. If you want to know how an engine or propeller upgrade will change the performance of the vessel, the app can do the calculations for you. If you are in the market for a boat, want to build a custom boat, or modify an existing hull, use the app to estimate displacement, range, required fuel capacity, and horsepower. App Features: • User inputs the vessel and engine specifications. • During trip or for trip planning, user only inputs wind speed, fuel, and vessel speed. Update these values throughout the trip to update range and engine calculations. • User can customize or update output after making changes to vessel or propulsion system. • User can update app with new vessel specifications after buying a new boat. Only purchase the app once. • Calculations are only updated with new input from user (saves battery life). • User input is saved on device but make a printout for backup and keep in vessel log. • Take screen shots to share. • Does not have maps or speedometer. Other devices or gauges can provide this information without draining your device’s battery. Find the tutorial and more information here: https://poseidonvesselmanagement.com/first-mate Why is this app not free?? • NO in app purchases, NO subscriptions, NO ads, NO data collection, NO locked features. • Rely on word-of-mouth advertising. • Provide a high-quality product to the customer at the lowest price. Poseidon Vessel Management does NOT collect any of your information, but feel free to tell your friends about our app!

About

GrowDiary

Features
Read full description

GrowDiaries is your all-in-one plant cultivation app, designed to empower growers of all levels. Easily document your grow cycles, track progress, and share your experiences with a vibrant community of over 350,000 enthusiasts worldwide. Access a vast library of over 90,000 grow diaries to gain insights, learn new techniques, and improve your yields. Engage in forums, participate in contests, and connect with official representatives from leading seed breeders and nutrient companies. Whether you're a beginner or a seasoned cultivator, GrowDiaries provides the tools and community support to elevate your growing journey.

Screenshots

First Mate4 screens
GrowDiary4 screens

Verdict

The call

The clearest difference is price: GrowDiary at Free against First Mate's $19.99. First Mate's advantage is ads (none vs shown) and device support (3 vs 1). On update cadence and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

GrowDiary is free to download; First Mate costs $19.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

First Mate ships an update every 3 weeks, GrowDiary every 2 weeks. The most recent releases landed on September 9, 2026 and September 14, 2026 respectively.

Scorecard4 real differences · 2 level
First Mate versus GrowDiary: the parameters behind the verdict, then further details
ParameterFirst MateGrowDiary
Price$19.99Free — better
Update frequencyEvery 3 weeksEvery 2 weeks — better
AdsNo — betterYes
In-app purchasesNoNo
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS14.5 — better16.4
Further details — not scored
Size3 MB44 MB
Age rating4+17+
DeveloperMatthew RicciardoGrowD soft s.r.o.

In-app purchases

None

First Mate

No in-app purchases

None

GrowDiary

No in-app purchases

Questions

Is First Mate free?
First Mate costs $19.99, with no in-app purchases.
Is GrowDiary free?
GrowDiary is free to download, with no in-app purchases.
Do First Mate or GrowDiary have ads?
GrowDiary shows ads; First Mate does not.
Which is updated more often, First Mate or GrowDiary?
First Mate ships an update every 3 weeks, and GrowDiary every 2 weeks. Most recently, First Mate was updated on September 9, 2026 and GrowDiary on September 14, 2026.

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