Anchor Scope Explained: The 7:1 Rule & Chain Length Formula
What anchor scope really means, the 7:1 rule, and the formula to calculate how much chain or rode you need at any depth — plus why it depends on depth, not boat length.
June 29, 2026
On the Water
Every way a boat stops: at anchor, alongside a dock, on a mooring buoy or stern-to a quay. These guides cover the method from choosing the spot to setting the alarm, why anchors drag and how to tell before the boat does, the lines and fenders that keep a boat still alongside, the anchors and chain that hold it, and the regulations that decide where you may stop at all.
19 guides
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The complete method — spot, scope, lay, set, watch — with a pass/fail test at every step.
Read the guideWhat anchor scope really means, the 7:1 rule, and the formula to calculate how much chain or rode you need at any depth — plus why it depends on depth, not boat length.
June 29, 2026
A windlass is a lifting machine, not an anchoring machine — and almost every expensive failure comes from asking it to do one of three jobs that belong to the engine, the chain stopper or the snubber. The drop, the handover and the recovery step by step, the current draw and duty cycle that explain the technique, why chain jumps the gypsy, what to do when the windlass dies, and why your chain counter is a guess with a decimal point.
August 1, 2026
Far enough that their swing circles never overlap. How to work out your swinging radius, a depth-by-depth spacing table (two 12 m boats on 5:1 in 5 m need ~75 m between anchors), who carries the responsibility when boats swing together, and why same-size boats still swing differently.
July 18, 2026
Everything you need to know about overnight anchoring — from choosing the right spot and setting your anchor properly, to monitoring through the night and handling changing conditions.
February 14, 2026
Understanding why anchors drag is the first step to preventing it. We break down the 7 most common causes and give you specific prevention techniques for each.
February 14, 2026
Anchor dragging is one of the most dangerous situations you can face at anchor. Learn the warning signs, what causes it, and how to prevent it before it becomes an emergency.
February 14, 2026
Night anchoring demands extra caution. Learn 10 essential safety tips for anchoring after dark — from choosing the right spot with limited visibility to setting up reliable overnight monitoring.
February 20, 2026
Single-handed anchoring brings unique challenges. From choosing the right anchorage to setting up your digital watch partner, here's how to sleep safely when sailing alone.
February 14, 2026
Bow and stern lines hold the boat in; springs hold it still. What each of the four lines does, the cleat hitch, tying up in a slip, allowing for tide, how many fenders and what size line — and the one push test to do before bed.
September 17, 2026
The slow approach, hand signals, four ways to get the pennant aboard, the catamaran bridle and chafe — then the part that matters: who laid the mooring, how much to trust it, and the 40 m alarm centred on the ball.
September 25, 2026
Med mooring is anchoring, and everyone judges it as docking — every eye is on the stern while the thing holding the boat is forty metres away at the other end. The manoeuvre in six stages with the failure and the tell at each one, the three different things people call Med mooring, how far out to drop and why too close is unrecoverable, crossed chains, and why the alarm you want on a quay is a creep alarm rather than a swing alarm.
August 7, 2026
Complete guide to boat anchor types including Rocna, Mantus, Danforth, Bruce, Delta, Spade, grapnel, and traditional anchors. Learn which anchor is best for your boat with expert comparisons, sizing charts, and performance data.
February 26, 2026
Discover which anchor types perform best in sand, mud, and rock bottoms. Expert comparison of Rocna, Mantus, CQR, Danforth, Bruce, and grapnel anchors with real-world performance data.
February 25, 2026
In most of the world anchoring is free — but not anywhere. Where the right to anchor comes from, the six places it never applies, a country-by-country table of what's free and what costs money, and the Mediterranean seagrass fines that reach six figures.
July 15, 2026
The Med's anchoring rules, country by country — where Posidonia seagrass makes anchoring illegal (fines up to €600,000 in the Balearics), what Croatia's vinjeta and Turkey's Blue Card actually require, which buoy fields are mandatory, and the mid-June-to-mid-September window when the rules bite hardest.
July 16, 2026
A region-by-region guide to overnight anchoring rules for sailors — covering Turkey, Greece, Croatia, Spain, France, Italy, and the Caribbean. Know the rules before you drop the hook.
February 28, 2026
Shout, throw, point, press MOB — then the Quick Stop, Figure-Eight, Lifesling or powerboat approach. Getting back to the person is the easy half; the lift over the freeboard is the part that fails, so plan it first.
September 26, 2026
How to run jacklines so a tether cannot reach the water, webbing vs Dyneema vs wire, tether length and the quick-release hook, when clipping on is not a judgement call, and what the OSR and ISO 12401 require.
September 26, 2026
Anchoring is not one action but five checkpoints — spot, scope, lay, set, watch — and every one of them has a pass/fail test. The complete guide to anchoring a boat: choosing the spot, calculating scope, laying the chain, power-setting, and verifying the hold before you relax, plus the mistakes behind almost all dragging.
July 26, 2026