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post #11 of Old 10-30-2017
RichH
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Re: What if No-Chain?

Chainless anchor rodes are possible. Such would depend on: 1. the 'penetration power' of the anchor, and 2. the fluke angle of the anchor. Inotherwords, the 'trigonometry' (especially during the 'setting phase') has to probably be equal to a partly chained rode.

The obvious functional 'advantage' of part chain or all chain rode is during the 'setting' (and re-setting under changing wind direction and changing current direction) of the anchor; the chain holds the anchor stock essentially level with the bottom and thus enables an approximate 15 'extra' angle (with 7:1 scope) during the 'penetration into the bottom phase' of anchoring.
In all probability one would have to initially 'set' such a chainless anchor with a ~10:1, or more, initial scope then haul in to ~7:1 ... all to get that initial setting angle of the flukes 'into' the bottom as is done with a part chain rode.

The Fortress double angle (choice of 32 fluke angle for 'sand' and 45 fluke angle for soft mud) would probably be my choice for a chainless rode ... just set it at the 45 angle and forget it; but, use an initial scope of 10:1 for sand and 7:1 for soft mud.
(However, Ive found that double angled Fortress anchors sometimes don't always easily 'reset' during ~180 current and wind shifts, as does the heavily-weighted tip 'plow-type' anchors)

Trigonometric (implied free body force diagram) analysis as attachment. The implication is that added chain gives weight/catenary and thus holds the anchor flukes in a much deeper penetration angle, especially during the 'setting' process. The analysis seems to imply a LOSS of ~10 scope angle due to NO catenary during the initial setting/digging-in phase; hence, the probable need to set such with a much longer scope during the 'setting' phase.
Correction to attachment: (TAN ^-1) 1/7 = .17 = 8
Attached Images
File Type: jpg Scope Analysis.jpg (114.2 KB, 18 views)

Last edited by RichH; 10-30-2017 at 01:09 AM.
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