Rather than following generic and unspecific advice how much chain to pay out when at anchor, use this app to calculate the amount of chain needed for the anchor to have the best possible grip - safety tailored for your vessel!

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 / bridle good enough to do the job?

The Anchor Chain Calculator allows you to calculate the minimally required anchor chain 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, how much of the swell it absorbs, and how much it reduces the anchor load. Including these dynamic and elastic effects is particularly important in shallow water.

You can also restrict the chain 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 have 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).

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.

You can store different vessel configurations by name and so can easily switch, e.g., between different snubber/bridle or vessel setups. These setups can be locked to prevent accidental overwriting.

The perfect addition to an anchor alarm / anchor watch for safer anchoring!
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What's New

Updated French and Danish online help
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Additional Information

Eligible for Family Library
Eligible if bought after 7/2/2016. Learn More
November 29, 2021
Current Version
Requires Android
4.1 and up
Content Rating
Offered By
Mathias Wagner (SAN)
Postfach 20 31 31, 20221 Hamburg, Germany
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