Ideal Catenary Angle

[Jackhulse]

I was always taught that if you start with incorrect assumptions, you will probably wind up with incorrect conclusions.

Nowhere have I ever read that the throat angle is based on anything other than the shank parallel to the seabed and the throat angle then based on penetration and holding.

A naval architect/marine engineer told me that the whole purpose of catenary/ increased scope is to create a near horizontal pull on the anchor, which tends to make the flukes bury deeper. The more vertical the pull, the greater tendency to pull the anchor back up to the boat.
I’m sure there is some ridiculous maximum of scope but there is a reason why you let out more scope in a storm to assure better holding
Jack Hulse
Endeavour 44 catamaran trawler “Two’s Company “
New Orleans

 

[Jackhulse]

Tried to post this earlier. A naval architect/marine engineer told me that the purpose of catenary/increased scope was to get the chain and rode as close to a horizontal pull as possible, since that causes the flukes to dig further into the bottom. On the contrary the more vertical the pull, the more you tend to pull the anchor up to the boat. That’s why you let out more scope for better holding and in storms, with all chain now, I try to use 5:1 in normal anchoring, 7:1 if blowing.
Jack Hulse
Endeavour 44 catamaran trawler “Two’s Company “
New Orleans

 

[Steven Cyr]

Scope will vary with weight of anchor, design, depth of water, size of ship, typr of rode, weight of rode etc...
If interested in learning more go to Peter Smith's website. This link is to cantenary section: https://www.petersmith.net.nz/boat-anchors/catenary.php
Cheers
Steve