Abstract: An improved fairlead reduces the problems associated with deploying and rieving a towing cable and its interconnected elongate instrumentation array. A pair of parallel rollers orthogonally disposed to a storage winch reel are spaced apart to present a smooth, protuberance-free surface to accommodate the elongate instrumentation array. A shell coaxially disposed about each of the cylinders is rotated to cover the smooth protuberance-free surfaces and present a pair of abrasion-resistant surfaces when the towing cable is reeled in or payed out. Since it is likely that the abrasion-resistant surface might be scored by the towing cable, rotating the abrasion-resistant surfaces out of the way to expose the protuberance-free accommodating surfaces when the array goes through the fairlead helps reduce the possibility of damage of the elongate instrumentation array during deployment and recovery.

Abstract: An explosive disconnect joins two portions of an underwater cable and an ctrical conductor extends from a squib to a remote detonator. The squib and conductor are cast inside a plug of epoxy or equivalent frangible material. Holes bored at opposite ends of the plug receive the two portions of the cable, for example, an anchor line and a buoy line. When the squib is detonated, the frangible plug disintegrates and an instrumentation package is buoyed to the surface for recovery. The nonmetallic explosive disconnect is waterproof, is corrosion resistent and is relatively inexpensive compared to other commercially available units.

Abstract: A tensioning device for submarine oceanographic structures includes a sure float having a pendent line suspended therebeneath and a vertical rod support attached to the distal end of the pendent line. An electrical motor attached to the lower end of the support provides ballast to hold the rod in a substantially vertical position and also provides mechanical motive power to turn two coaxially mounted hydrodynamic screws. These screws are attached to the support so as to provide a propulsive force for the support and surface float system. A hitch employing standard marine hardware connects the tensioning system to an underwater structure such that this propulsive force is used to tension the structure. Power for the electrical motor is provided by a source of electrical power housed in a small surface vessel and effectively connected to the surface float and pendent line.