Comparison

AnchorChainCalculator vs Plan M8

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

Head to head
About

AnchorChainCalculator

Calculate the optimal amount of anchor chain or rope for secure anchoring based on vessel characteristics and sea conditions. Provides detailed load calculations and accounts for dynamic effects like swell and gusts. Supports both metric and imperial units, with options for chain-only or mixed rope/chain setups.

Highlights
  • Physics-based anchoring calculations
  • Customizable vessel and sea conditions
  • Chain-only or mixed rope/chain support
  • Load and swell absorption analysis
  • Metric and imperial unit support
  • Multiple vessel configuration storage
  • Basic and Expert modes
Features
Read full description

Rather than following generic and unspecific advice how much chain or rope to pay out when at anchor, use this app to calculate the right amount of chain or rope needed for the anchor to have the best possible grip – safety tailored for your vessel! This app has been developed by a sailor living at anchor. It is based on physics rather than rules. Only too often does anchoring advice boil down to: Use a scope (i.e. ratio of chain length to water depth) of 3:1 in calm weather, and increase this to 5:1 or 7:1 as the wind picks up. This advice is independent of your vessel’s characteristics, independent of water depth, swell, or even the wind strength. So, is a scope of 7:1 still good enough for the storm tonight? Is the snubber or bridle you are using good enough to keep you safe at anchor? The Anchor Chain Calculator allows you to calculate the minimally required anchor chain and/or rope length based on a number of vessel characteristics and sea / weather conditions. It tells you what load the anchor will have to bear, and when you are using a snubber, bridle or rope, how much of the swell it absorbs, and how much it reduces the anchor load. When anchoring in shallow water it is particularly important to include these dynamic and elastic effects caused by strong swell and gusts. The app can work with a chain-only scenario as well as with an arbitrary mix of rope and chain. So, despite its name, it can also deal with a rope without any chain at all. ;) You can also restrict the chain or rope length, if you have to - perhaps because of nearby neighbours or obstacles - and get information how this restriction affects the anchor load and the angle at which the chain pulls at the anchor. The app has two modes of working: Basic Mode and Expert Mode. With Basic Mode you will be able to use the app right away, whilst Expert Mode allows you to enter more technical details of your boat if you know them. You can use either metric units (metres, daN / kp, and mm for chain thickness) or imperial units (feet, lbs, and inch for chain thickness). You can store different vessel configurations by name and so can easily switch, e.g., between different snubber, bridle, rope or vessel setups (e.g., a snubber for the lunch stop, another snubber for normal usage, and a third longer and even more elastic snubber for really bad weather). These setups can be locked to prevent accidental overwriting. This app is also great for playing through all kinds of "what if?” scenarios. It will help you to plan ahead and be better prepared. The perfect addition to an anchor alarm / anchor watch for safer anchoring!

About

Plan M8

Features
Read full description

Yacht Maintenance Made Easy - Designed for marine engineers, captains and owner or operators. Improves reliability, saves time, and creates transparency. Implementing a structured planned maintenance schedule such as Plan M8 not only ensures your equipment and machinery on board is maintained through continuous monitoring at all times, It assures all your yacht maintenance is planned. Plan M8 provides a comprehensive and structured task-based scheduling of all required, recommended and manufacturer specific planned maintenance tasks of a vessel's components. Plan your maintenance ahead of time, pre-order spares and never miss a component with our pre-generated templates for your vessel. You will see a reduction in downtime and the need for emergency repairs as equipment is maintained before it fails. Operating costs are reduced as optimum service life is given to components. As you continue to use Plan M8, a detailed maintenance log of your vessel is being build. Proper records will be kept that can be easily passed onto new crew, contractors, surveyors, and prospective buyers. Get more transparency about your yacht maintenance status with all involved through our easy-to-use application; your "Plan Mate".

Screenshots

AnchorChainCalculator4 screens
Plan M84 screens

Verdict

The call

The clearest difference is price: Plan M8 at Free against AnchorChainCalculator's $12.99. AnchorChainCalculator's advantage is iOS requirement (10.0 vs 15.0). On update cadence, ads, in-app purchases and device support 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

Plan M8 is free to download; AnchorChainCalculator costs $12.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

AnchorChainCalculator ships an update every 3 weeks, Plan M8 fortnightly. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

Scorecard2 real differences · 8 level
AnchorChainCalculator versus Plan M8: the parameters behind the verdict, then further details
ParameterAnchorChainCalculatorPlan M8
Price$12.99Free — better
Rating5.0 (5 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings5 — better—
Update frequencyEvery 3 weeksFortnightly — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS10.0 — better15.0
Further details — not scored
Size12 MB51 MB
Age rating4+4+
DeveloperMathias Wagnercoara OU

In-app purchases

None

AnchorChainCalculator

No in-app purchases

None

Plan M8

No in-app purchases

Questions

Is AnchorChainCalculator free?
AnchorChainCalculator costs $12.99, with no in-app purchases.
Is Plan M8 free?
Plan M8 is free to download, with no in-app purchases.
Do AnchorChainCalculator or Plan M8 have ads?
Neither AnchorChainCalculator nor Plan M8 shows ads.
Which is updated more often, AnchorChainCalculator or Plan M8?
AnchorChainCalculator ships an update every 3 weeks, and Plan M8 fortnightly. Most recently, AnchorChainCalculator was updated on October 24, 2026 and Plan M8 on October 25, 2026.

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