Friday, 10 April 2015

What a drag...

As we noted in an earlier post, "everyone drags anchor sometime".

We have an excellent anchor (25 kg Rocna), all-chain rode, and we are conservative in anchoring by have significant scope usually 5-or-6-to-1. Until recently, we had not dragged with the Rocna.

(But we have dragged with other anchors -- especially CQRs -- in previous years.)

Given that anyone/everyone drags sometime, it is comforting to anchor with a lot of space between boats and/or the shore; at least, when possible.

As we mentioned in our preceding post, the other night we dragged 60 feet during coroumels in Caleta Partida. The winds were no more than 20 kn and the seas negligible, and we had at least 6-to-1 scope. So, it was a surprise -- no, a shock -- that we had dragged. (Later in the night, after we let out extra chain, a neibouring boat, over 200 feet away, shined its spotlight to alert us that we had dragged; david was awake and replied quickly; the other boat told us later that once he knew we were already awake and aware, he slept soundly.)

Anchor watch showing positions relative to anchor: initial, drag, drag+extra chain out
The Vespermarine Watchmate 850 Anchor Watch screen plots the boat position relative to the anchor position every several minutes. What is obvious from the screenshot is that were holding fine, then there was an approximately 20 degree shift in wind position, then a new set on points indicating a new positin 60 feet back and a different angle. Likely, the wind shift pulled the dug-in Rocna out and it took 60 feet to dig-in again. (The screenshot also shows when we let out extra chain.) We did not drag any further.

This dragging is unusual; normally the Rocna resets very quickly with a significant wind change. We will have to chalk this up as being a rare case, and be glad we had lots of space to drag. 

Everyone drags sometime.

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