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2011 BentProp Progress Report # 08

P-MAN XIII Update #08 - BentProp torpedoes its first (already-sunken) ship

07 February

Our schedule starts at 0500 in the morning, (4:00 in the afternoon Michigan time) with a pickup by a boat near our hotel at 0630. We are than ferried out to a much larger ship, where we’re assigned additional team members and we prep the sonar equipment we’ll be using in that day’s work.

Originally, we collected data (meaning taking Sonar pictures of the seafloor) until noon-ish. Then we would break for lunch (go to the nearest food source that had a boat dock out front). We would return to the sonar survey site after lunch and finish out the day. Our new schedule is to work right through lunch and quit a little earlier, when the sun really starts to bake us.

The technique of using side-scan sonar comprises towing a 40-pound, bright yellow torpedo-shaped towfish (well, it started out bright yellow, but by hitting numerous submerged “things”, the nose of it is now kind of a lead gray). This towfish is attached a very long, very expensive (more about that later) Kevlar-coated cable that allows it to send out a continuous series of “ping’s” and then translate that data back to the boat. Let me make it exceedingly clear that the last thing one wants to do is make physical contact with the sea floor. But when you have unexposed sea mounts and these coral reefs that appear out of nowhere, unintentional contact happens.

A case in point (and then I have to get ready to go), we’re cruising along, minding our own business as the equipment is collecting data, when we get an abrupt shallow water sounding alarm. The sea floor has just jumped from 116 feet to 75 feet and our torpedo-shaped towfish is certainly sailing along in the vicinity. We leap to our feet and commence to start hauling in the cable in an attempt to get the “fish” up to an altitude that will allow it to clear the obstacle.

Wham! The towfish has stopped, dead in its track. The enormous tension now put on the cable starts a series of safety events. The first is the safety strap separating. POW. It sounds like a pistol shot, and then the cable stowed on deck in beautifully laid coils starts uncurling off the deck and disappearing over the stern. Whirl, Whirl, Whirl. And finally the boat throttles are jammed into reverse until everything settles down.

Bent Prop had just sunk its first sunken ship by nailing it broadside with a torpedo/towfish. Man, I wish I had had a video camera on the nose of that sucker.

Paul
 

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