Anchoring, how to stop dragging and be secure.

Take anchoring seriously and you can be secure in almost all conditions. Many anchors are only suitable for ‘normal’ conditions, they fail in strong wind or a difficult seabed. Anchor dragging is a menace in any anchorage, and it’s not necessary.

The new generation, high holding power anchors are a big improvement over the traditional anchors, particularly on bottoms with poor holding. But I suggest using a size larger than recommended for extra security when it matters.

The traditional chain scope calculation, using a simple multiplier, is not correct due to the curvature of the chain. 15m (50ft) plus double the depth is better calculation. But always put out more chain in challenging conditions.


Thanks to John Bellagamba for the Kata Beach video
   • 2010 Phuket King's Cup Regatta Accident: S...  
and NauticTube    • Dramatic end to the Phuket Kings Cup Regat...  

Independent anchor performance test charts.
https://www.petersmith.net.nz/boat-an...

Lewmar Delta size chart
http://www.lewmar.com/sites/default/f...

RYA - Things to think about when anchoring
https://www.rya.org.uk/newsevents/e-n...

Underwater Manson Supreme
   • Underwater Footage of a Manson Supreme Anchor  

Thanks to Ultimate Ambient Noise Soundzzz for the ‘relaxing’ storm video
   • 🎧 Thunderstorm at Sea with Heavy Rain | Ra...  

Caterary formula.
Chain length = Sqrt(2 x Horiz load x Depth/Chain wt + (2 x Depth))
Where Chain wt = Chain mass per unit length x 6.9/7.9 to allow for buoyancy
http://home.earthlink.net/~w6rmk/math...
Formula works for metric or imperial.
The catenary shown is for 10mm chain (2.28kg/m), with a 100kgf horiz load. This matches observations of the chain on our 45ft yacht in about 25kts of wind.