Tugs for seismic

The tugs Atlantic Fir and Beverly M 1 are tied up at pier 324, nose to nose, readying for BP's 2014 seismic expedition off Nova Scotia. The are is so heavily fenced and secured, that photography poses a bit of a challenger.From my perch I couldn't tell if they are being fitted with any special equipment for their work, except for supplementary satellite communication domes.

BP has hired six actual seismic boats, two suppliers and these two tugs to act as picket boats or chase boats.
They seem an odd choice to me, since neither one would be a natural pick for their sea keeping abilities. They are undoubtedly able towing vessels, but towing does not seem to me to be a necessity in seismic work.

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