Wednesday, April 28, 2021

2021 Round GB. Day 13/14 - Anchor Watch

Tuesday bought stronger than expected winds from the east which caused problems in the anchorage which is fairly exposed to wind from that direction, especially at high tide when guarding reefs and sand banks are covered. This was not an issue as the tide was coming in as the wind and tide were coming from the same direction, As soon as the tide changed things became difficult, the strong (2 knot) tide in the anchorage tried to hold the boat heading to the west but the wind which was now 20 knots with gusts above was pushing the boat into the tide often overcoming it causing the boat to push over the anchor then swing round, this was exacerbated by waves, not that big but steep and close together, caused by the wind over tide.  

The boats position over 24 hours from Tuesday morning. The anchor
symbol is the approximate position of the anchor after adjustment
during the evening, its in about 6 metres of water at low tide and
about 11 meters at high tide (we are one day off a spring tide).
The anchor was on the end of just under 50 metres of chain. The
circle is the guard area, if the boat goes out of it an alarm sounds - I
had the software running on two devices, with different limits to be sure.

The dense plots to the left of the plot above show the boats position before the wind arrived and the tide changed and the boat was stable. When the tide changed at about 16:00 things started to get wild with the boat swinging all over the place, exacerbated by the tide being slightly stronger to the south (bottom of the plot) than to the north, after an hour or so of these gyrations the anchor could be heard grumbling, probably being literally screwed out of the sea bed which at least in the shallower water, appears to be relatively thin sand and mud over rock.

With rain showers and strong winds I was suited up ready to go outside and had an early dinner. It was not long before it was necessary to take some action and I motored hard astern to reset the anchor and I expected to be on "anchor watch" until low tide at 22:00, monitoring the situation and making small adjustments to the rudder (otherwise locked in position) to try and keep the bow from riding over the anchor chain causing damage.

Fortunately at about 20:00 the wind backed round to the north east and everything calmed down a little. On the right of the plot the dense areas SE and NW of the anchor symbol are the boats position after things calmed during the flood and ebb tides respectively. 

Now, 10:15 on Wednesday, the wind is about NE at 15 knots, the sea calm and boat is stable and comfortable which is just as well as, if the wind is as forecast, I am likely to be here until Friday morning before heading off to Peterhead.

Click here for Day 15, ashore on Lindisfarne.

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