# MMO Range Finder — Precision for your Mitigation

> Calculates distances for marine mammal observer mitigation during acoustic surveys. (iPhone/iPad app by James Keating.)

- Source: https://appshunter.io/ios/app/mmo-range-finder/id1258748649 (this page in markdown: same URL + `.md`)
- Developer: [James Keating](https://appshunter.io/developer/1258748648)
- Category: Utilities, Navigation
- Price: $0.99
- Rating: 5.00/5 from 1 App Store ratings · 1 written reviews indexed
- Age rating: 4+
- Requires: iOS 10.3 · 43 MB
- Languages: American English
- Released: 2017-07-14
- Data updated: 2026-09-05
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/mmo-range-finder/id1258748649/reviews.md

## What is MMO Range Finder?

Marine Mammal Observers mitigate for the potential impact of sound exposure on marine fauna during geophysical surveys, naval active-sonar exercises, UXO clearance or civil engineering projects. 

This app will assist the MMO making mitigation decisions by calculating the distance from the animal to the source of acoustic interference using a trigonometric cosine function. The MMO simply enters the distance and bearing to the TARGET and SOURCE from their observation position and the app calculates the rest.

This app is loaded with features to make allow to keep focused on the detection (See the user manual for a detailed description):
Fix compass bearing to animal and source by pointing device and pressing button.
Convert binocular reticules to distance  by entering the number of reticules between horizon and animal and pressing the reticule button (per formulae in Lerczack and Hobbs, 1998).
Set up to 3 unique observation locations to define height above sea level (required for accurate reticule conversion).
Save data to the log for each sighting and export in .csv format for your own mapping and analyses needs.
Shows vessel position, mitigation zone and projected fauna sightings on the map. Map also displays latitude, longitude, course and speed.
Press the radar button and the map will orientate to the vessel point of view. Sightings labels will be updated live with the distance to source and the bearing from the vessel for ease of re-sighting.
Fully customise the MMO parameters. Specify anything from your binocular MILs per reticule, mitigation zone size, choose a ramform hull as your maps ship symbol and much much more!

Disclaimer:
MMO Range Finder App should be used as a reference tool and is only as precise as the users ability to range find. Any decision making is the responsibility of the user. If in use, the compass and GPS location should be verified often.

## Key features

- Calculate distance using trigonometric cosine function
- Fix compass bearing by pointing device
- Convert binocular reticules to distance
- Set up to 3 unique observation locations
- Save and export sighting data in .csv format
- Display vessel position, mitigation zone, and sightings on map
- Customise MMO parameters

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/mmo-range-finder/id1258748649/reviews.md

### 5/5 — Crucial

*2026-05-06*

Jah bless whichever bored MMO developed this… a wonderful tool proven over and over again in the field… once you get it dialed in you have complete confidence and a demonstrable methodology when estimating distances for mitigation (and betting fun😆)

## Frequently asked questions about MMO Range Finder

### What is MMO Range Finder used for?

MMO Range Finder is a utility app designed to assist Marine Mammal Observers in calculating the distance between animals and acoustic sources. This is crucial for making informed mitigation decisions during various types of surveys and projects.

### How does MMO Range Finder calculate distances?

The app utilizes a trigonometric cosine function. Users input the distance and bearing to the target and source from their observation position, and the app computes the necessary distances for mitigation.

### Can MMO Range Finder help with visual observations?

Yes, it can convert binocular reticule readings to distance by using a specific formula, as referenced in Lerczack and Hobbs (1998). It also allows for setting up observation locations with height above sea level for accuracy.

### Does MMO Range Finder offer data logging and export?

Yes, the app allows users to save data for each sighting and export it in .csv format. This is useful for subsequent mapping and analysis of the collected data.

### What map features are included in MMO Range Finder?

The map displays vessel position, the mitigation zone, and projected fauna sightings. It also shows latitude, longitude, course, and speed, and can orient to the vessel's point of view for live updates on sightings.

### Is MMO Range Finder free to use?

No, MMO Range Finder is a paid application. It is available for purchase on supported devices for a one-time fee of $0.99.

### How often is MMO Range Finder updated?

The latest version of MMO Range Finder is 4.0.1, which was last updated on September 25, 2018. Users can expect updates to improve functionality and address any issues.

### What devices support MMO Range Finder?

MMO Range Finder is compatible with iPhone, iPad, and iPod devices. It is suitable for users who require its specialized utility functions on Apple mobile devices.

## Version history (last 5 releases)

### 4.0.1 — 2018-09-25

This latest update to the MMO Range Finder includes the following (and much much more!)

Now equipped with maps. Your sightings can be displayed on a map with your ship and mitigation zone.
Choose between conventional, 'x-bow' and 'ramform' ship symbols for the map, all correctly scaled to the real ship dimensions.
Press the radar button to show the map orientated to the vessel heading. 
Radar button also displays the distance from the target to the center of source as well as the bearing from the ship to the target for ease of re-sighting.
Compass direction indicator guides you back to your sighting.
Swipe left on any text-field to delete.
Your data can be saved to the log and exported as a .csv using a variety of methods (email, Dropbox, iCloud, etc).
A user manual for the MMO Range Finder can be accessed from the app.
All app settings are now found within the app. User does not need to leave app to make changes.
Added option to calculate the great circle distance between the target and source when GPS is enabled.
Bug fixed related to pressing reticule converter button more than once.

### 3.1.3 — 2017-11-27

- general overhaul of layout
- fixed some minor bugs and improved usability
- user can now set default distance to source from each of the 3 MMO observation locations. This will fill out the Source Distance text field when you select your location saving valuable time
- removed screenshot button

### 2.1.4 — 2017-08-28

Added binocular reticule converter; converts from reticules (MIL) to distance (m).
Added new setting options for optimisation of the reticule binocular; this includes 3 default observer heights and MIL settings so you can configure your own binoculars per manufacturers spec.
Added basic and advanced configurations for the discerning MMO.
Clear button no longer erases source distance, convenient to keep it as its usually a constant anyways.
Moved bearing fix and reticule calculator buttons inside their relevant textfields.
Fixed several minor bugs from last version.
General tidy up of layout.

### 1.2.2 — 2017-07-17

Added simplified "Fix" icon for fixing the compass bearing to Target and Source.
Added clear button. User can quickly clear the data for either Target or Source.
Fixed minor UITextfield resizing bug.

### 1.2.1 — 2017-07-14

No release notes.

## Apps similar to MMO Range Finder

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [iTest.](https://appshunter.io/ios/app/itest/id6484069424) | 4.4 (50) | $0.99 | Utilities |
| [GovConnect - GY](https://appshunter.io/ios/app/govconnect-gy/id6755823171) | — | Free | Utilities |
| [Twind](https://appshunter.io/ios/app/twind/id6478852745) | — | Free | Utilities |
| [EVPoint - Charge Forward](https://appshunter.io/ios/app/evpoint-charge-forward/id6478470428) | — | Free | Utilities |
| [Timekept](https://appshunter.io/ios/app/timekept/id1156065589) | 4.5 (17) | $2.99 | Utilities |
| [Kelvin TOP-SET®](https://appshunter.io/ios/app/kelvin-top-set/id1491145623) | — | Free | Utilities |

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-05.*