Comparison

TVMDC Sailing & Marine Navigation Calculator vs Radar Plotting

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

Head to head
About

TVMDC Sailing & Marine Navigation Calculator

This app calculates corrections between true, magnetic, and compass bearings. It also computes set and drift from known fixes and determines the course to steer, factoring in all navigational corrections. Ideal for learning chart navigation.

Highlights
  • TVMDC corrections (True, Magnetic, Compass)
  • Set & Drift calculations from two fixes
  • Course to Steer (CTS) calculation
  • Variation and Deviation corrections
  • Graphical sailing triangle
Features
Read full description

A Simple to Use, Marine Navigation Calculator App - for Sailors and Navigators learning to use Charts. The TVMDC App performs three functions: - * Instant TVMDC corrections between True, Magnetic and Compass bearings. * Set & Drift Calculations from two known Fixes. * Calculation of "Course to Steer" (CTS) based upon a Destination while factoring in both TVMDC and 'Set & Drift' corrections. Allows you to move between True, Magnetic and Compass bearings instantly. A True, Variation, Magnetic, Deviation, Compass (TVMDC) Calculator. Ideal for Sailors who are learning to Navigate with Charts. Includes corrections for : Variation, Annual Magnetic Variation Drift, a boat's Deviation, Set and Drift factors. Simple to use: Input values form the your nearest Chart's Compass Rose: including Variation and Annual Increase. Along with your boat Compass's Deviation. The Calculator will instantly correct between any: True, Magnetic and Compass bearings. Add two known fixes along with your boat's Heading and Speed through the Water. Press Calculate and the App will display your calculated "Set and Drift" values along with a graphical sailing triangle. Any heading or bearing is adjusted for Magnetic Variation and Deviation. Add your Destination and the Calculator will provide your best Course to Steer: factoring in TVMDC and Set and Drift errors. American Sailing Association (ASA) course 105 (Navigation) is an ideal back ground for the App. Also, wikipedia's TVMDC description : http://en.wikipedia.org/wiki/TVMDC YouTube TVMDC App Introduction tutorial: https://www.youtube.com/watch?v=u4d5wCgPxwg Extensive Help at: http://www.arintoapps.com Runs on iPhones 5, 6 and 6+, 7, 7+ in Portrait mode ONLY. Planning on new versions and extensions; so please feedback feature requests?

About

Radar Plotting

This app offers advanced radar plotting for maritime navigation. It allows users to calculate critical encounter data, plan maneuvers, and analyze complex scenarios with interactive visualizations. Designed for training and decision support, it aids in understanding vessel interactions.

Highlights
  • Kinematic calculations (CPA/TCPA, aspect)
  • True and relative speed estimation
  • Evasive maneuver planning with COLREG guidance
  • Rescue and escape scenario planning
  • Double-target analysis
  • Current and drift estimation
  • Interactive radar canvas with playback
Features
Read full description

Radar Plotting provides advanced radar-plotting capabilities for iPhone and iPad. Compute CPA/TCPA, estimate true motion, plan evasive/rescue/escape manoeuvres, and analyse two-target encounters — all visualised on an interactive radar sheet. Highlights: - Precise kinematic calculations (CPA/TCPA, aspect, true & relative speed) - Evasive manoeuvres with COLREG guidance - Rescue & escape planning, including scenarios with faster vessels - Double-target handling - Current/drift estimation - Interactive canvas with adjustable scales and animated trajectory playback - Import/export via QR code and PDF report generation Safety note: This app is for training and decision support. It does not replace certified navigational equipment or official procedures. Always follow COLREG and local/company rules.

Screenshots

TVMDC Sailing & Marine Navigation Calculator4 screens
Radar Plotting3 screens

Verdict

The call

The clearest difference is review sentiment: TVMDC Sailing & Marine Navigation Calculator at 100% against Radar Plotting's 50%. TVMDC Sailing & Marine Navigation Calculator also leads on price ($4.99 vs $7.99) and iOS requirement (8.2 vs 15.0). Radar Plotting's advantage is rating (5.0 vs 3.0). On ratings volume, update cadence, ads 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

TVMDC Sailing & Marine Navigation Calculator costs $4.99 and Radar Plotting $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Radar Plotting holds the better App Store score, 5.0 against 3.0. Both are backed by a comparable volume of ratings — 2 and 1 respectively. Written reviews complicate that: 100% of TVMDC Sailing & Marine Navigation Calculator's written reviews are positive against 50% of Radar Plotting's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

TVMDC Sailing & Marine Navigation Calculator ships an update every 6 months, Radar Plotting every 5 months. The most recent releases landed on November 11, 2026 and November 6, 2026 respectively.

Scorecard4 real differences · 6 level
TVMDC Sailing & Marine Navigation Calculator versus Radar Plotting: the parameters behind the verdict, then further details
ParameterTVMDC Sailing & Marine Navigation CalculatorRadar Plotting
Price$4.99 — better$7.99
Rating3.0 (2 ratings)5.0 (1 ratings) — better
Positive reviews100.0% of reviews — better50.0% of reviews
Number of ratings2 — better1
Update frequencyEvery 6 monthsEvery 5 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS8.2 — better15.0
Further details — not scored
Size13 MB17 MB
Age rating4+4+
Developerpeter hopperGiacomo Gabriele

Customer experience

TVMDC Sailing & Marine Navigation Calculator

All ratings2 ratings
Positive50.0%
Neutral0.0%
Negative50.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Radar Plotting

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

In-app purchases

None

TVMDC Sailing & Marine Navigation Calculator

No in-app purchases

None

Radar Plotting

No in-app purchases

Questions

Is TVMDC Sailing & Marine Navigation Calculator free?
TVMDC Sailing & Marine Navigation Calculator costs $4.99, with no in-app purchases.
Is Radar Plotting free?
Radar Plotting costs $7.99, with no in-app purchases.
Which has better reviews, TVMDC Sailing & Marine Navigation Calculator or Radar Plotting?
Radar Plotting is rated higher. TVMDC Sailing & Marine Navigation Calculator averages 3.0 out of 5 from 2 ratings, while Radar Plotting averages 5.0 from 1 ratings.
Do TVMDC Sailing & Marine Navigation Calculator or Radar Plotting have ads?
Neither TVMDC Sailing & Marine Navigation Calculator nor Radar Plotting shows ads.
Which is updated more often, TVMDC Sailing & Marine Navigation Calculator or Radar Plotting?
TVMDC Sailing & Marine Navigation Calculator ships an update every 6 months, and Radar Plotting every 5 months. Most recently, TVMDC Sailing & Marine Navigation Calculator was updated on November 11, 2026 and Radar Plotting on November 6, 2026.

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