Scope for anchoring in deep water?

[GHA]

Btw, you can use http://www.awelina.co.uk/anchor_rode/rode_length_graph_only.html to plot rode length vs depth for arbitrary mixes of chain and rope, and for a seecified angle above horizontal at the anchor. See (and let me know) what you think.

Nifty bit of javascript :encouragement: :encouragement:
Hope you don't mind me pinching that to live on the mighty raspberry pi.

Though ,like the graph I was messing about with, great to think about the physics but so many other factors involved to use as a be all and end all. Like what the bottoms like, available space , how gusty it is and do the gusts come from everywhere etc etc

 

[GHA]

He got scope as metres, as did I, because your 'y' axis was labelled ambiguously. Scope may indeed be considered as a ratio, but it can equally be expressed as a distance. If, prior to dropping your hook you inquire of an anchored boat what scope it has out, I suspect you'll get (and possibly expect) an answer in absolute units.

But mainly, thanks for the graph. Interesting.

Seems so, though TBH I've never thought of it as anything but a ratio and quick google seems most others do, not that it matters now we know what we're looking at is ratio of chain to depth.

Text on the graph now changed so no mention of scope.

 

[RichardS]

Btw, you can use http://www.awelina.co.uk/anchor_rode/rode_length_graph_only.html to plot rode length vs depth for arbitrary mixes of chain and rope, and for a seecified angle above horizontal at the anchor. See (and let me know) what you think.

That's interesting to play with. With my cat and 10mm chain and a Rocna I'm glad I've standardised on 5:1 in all depths rather than the 3:1 which often gets mentioned. 3:1 is clearly marginal in too many situations using the parameters on the graph.

Richard

 

[vyv_cox]

That's interesting to play with. With my cat and 10mm chain and a Rocna I'm glad I've standardised on 5:1 in all depths rather than the 3:1 which often gets mentioned. 3:1 is clearly marginal in too many situations using the parameters on the graph.

Richard

I normally use 4:1 but let more out in stronger winds. Seems perfectly OK with the Rocna, although I have watched it many times with all the chain off the bottom, angle of perhaps a couple of degrees but maybe more at the limits of boat yaw. I recall that Mantus claimed a scope of 2.5:1 was sufficient for their anchors.

 

[sailaboutvic]

All this maths has my head spinning , I'm a 5/1 man unless there isn't the room then it's 4/1 or even 3/1 . We found even with a full blow boarer blowing using all 10mm chain and an 20 Kg Rocna we slept soundly .
We now just changed to an 25KG Rocna has the new to us boat is 16tons , be interesting how this will work .