zondag 29 maart 2015

Cue Calibration and Dolphins

Saturday 28th 2015

Rough seas today with 6 meter swell. Making slow progress on western transect, average speed a steady 4 knots. Estimated time to complete this leg of the survey was 30 hours. With little option we decided to shorten the next two transects to ensure we are not out when the force 10 hits the next evening. 

Waves crashing over the bow of the Tridens.

.... meanwhile somewhere below deck, I (Helen) spot a common dolphin outside my cabin window. In quick(ish) response I grab my camera and make for the bridge. Unfortunately I was too slow to even see them again, let alone get any photographic evidence (three flights of steep stairs is a real challenge in rough seas). Will have to try harder next time! However, the local seabirds (mostly gannets and fulmars) are always keeping us company on our voyage and always look far more content with the waves than some of us on board look in these conditions.

A gannet named Janet floating above the waves
As for fish there were very few marks seen on the echosounders throughout the day and therefore no fishing was carried out.  

Sunday 29th March 2015

After an uneventful night on acoustic watch, the morning offered a stunning dolphin display....at least for those who were awake. A pod of around 100 common dolphins (Delphinus spp) surrounded the boat and swam with us for about half an hour – something which is always nice to see.

Common dolphins jumping in the Tridens wake.

As the weather is predicted to get much worse over the next few days we headed for Loch Duich on the west coast of Scotland to do a calibration of the acoustic equipment. The conditions in the Loch are ideal for calibration of the EK60 echosounders. Deep water (50 – 105 m), small swell, little to no tidal current, relatively sheltered from the wind and very few fish below us (fish can interfere with the calibration as they often swim across the place in the beam we are interested in).

Once successfully calibrated, we will stay at anchor and spend the night in Loch Duich. We will head to either Kyle (132 km west of Inverness or 20 km from the Tridens) or Stornoway (Isle of Lewis) tomorrow morning and wait out the bad weather. We’ve already researched the local pubs in the area.

Flying the Scottish flag as we enter Loch Duich for calibration. 

The crew are hard at work erecting the calibration booms.

Will we fit? It’s a narrow passage en route to the calibration site further down the loch.

Being chased by rain and snow down the loch

Everyone settling in for a night of calibration.

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