NESW
Guides

Set up anchor alarm and geofence

NauticCalc on iPhone — matching the topic of this article.

NauticCalc app screenshot

Prerequisites

  • GPS active
  • Anchor set with adequate scope

Step 1: Open anchor alarm

In Anchor alarm save current position as anchor point.

Step 2: Radius

Typically: part of scope plus swinging margin. Too tight → false alarms; too wide → late warning.

Step 3: Alert

Leaving the geofence triggers the app. Complements watchkeeping — not a full anchor watch replacement.

Read next: GPS guide · Anchor alarm