Resource Centre

Anchoring Guides

Practical, no-nonsense advice on anchoring and anchor alarms — written from 30,000+ nautical miles at anchor, not a spec sheet.

Anchoring well is a skill, and a good anchor alarm is the backstop that lets you sleep once you have set the hook properly. These guides cover both — from getting your scope right to setting a watch radius that protects you without crying wolf. Free to read, written by Adam Harvey.

Anchor Alarms

Everything about keeping a reliable electronic anchor watch.

Start here · Pillar guide

How to Set an Anchor Alarm

What an anchor alarm is, how it works, how to set the right radius, and how to avoid the false alarms that make sailors stop trusting them. The complete guide.

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What radius should you set?
The setting most people get wrong — with worked examples by boat size.
Anchor watch vs anchor alarm
Two terms, not quite the same thing. What each means and when you need which.
Why boats drag anchor
The seven real causes of dragging, and how to prevent each one.
Best anchor alarm apps
An honest comparison of the leading iPhone options for 2026.
Anchoring Technique

Getting the boat well anchored in the first place — the alarm is only as good as the set beneath it.

Start here · Pillar guide

How to Anchor a Boat

Choosing a spot, reading the bottom, calculating scope, setting the hook and testing it, then keeping watch overnight. A step-by-step guide to anchoring safely.

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Anchor scope explained
The 7:1 rule, measuring depth correctly, and a scope table by depth.
How much anchor chain?
Sizing your rode for the cruising you actually do.
Anchor swing circle
How much room you need, and how to judge it in a crowded anchorage.
About the author
Who writes these guides, and why HoldFast exists.