Scope the high. Swing the low.
Built from TMG Yachts’s film of Joe Fox anchoring a Lagoon 42. He shows the six parts of the job and the chain multiples he actually uses. He does not run a 24-hour tide. A deployment is not successful here until both of those numbers have been taken off the tide chart for the whole stay.
Watch the film · Read TMG’s notes
Scope ratio, checked at high water
Rode ÷ roller depth
Deepest moment of the next 24 hours. Add the bow roller. This is when a short scope lifts the anchor.
Swing ratio, checked at low water
Reach ÷ roller depth
Shallowest moment. The same chain reaches further across the bottom, and the stern is still a boat-length beyond that.
Passed means 80% on the quiz and a recorded plan for the assessment anchorage that clears both gates. The sample tides are a worked chart, not a forecast for any real harbour.