8-inch (circumference) Polypropylene Braided Line 



Four lengths, 1,600 feet each, were long-spliced together. This line, having a breaking 

 strength of 160,000 pounds, was available if required. 



TOGGLE BAR AND STERN HOOK 



A toggle bar was fabricated in 1968; however, several possible weaknesses existed: 

 (1) the eye was underdesigned so that it would pull out if the pull were exerted at an angle of 

 5" or greater; (2) high local stresses might occur in the hull to cause deformation of the hull 

 and yielding in the upper flange of the toggle bar; and, (3) two existing serious design faults 

 indicated that the toggle bar was generally of inadequate design and that additional faults 

 were likely to surface should the bar be used. 



During outfitting for 1969 salvage operations, the toggle was redesigned and made of 

 80-pound steel plate contoured to fit the sphere of ALVIN. However, this toggle was un- 

 acceptably heavy and required excessive syntactic foam to be added to reduce its weight to 

 that which ALUMINAUT could handle in the water. Nine holes were cut into the bar to 

 lighten it; however, the weight problem, though alleviated, was not solved. 



On 1 1 August 1969, a toggle was made of 2-inch aluminum plate, contoured to fit 

 ALVIN's sphere in order to broaden the area of contact and reduce local stresses. This de- 

 vice was tested in both air and water and was found satisfactory to handle. 



A 9-foot-long toggle bar handle was constructed using a 1-inch wire rope enclosed in an 

 aluminum pipe for rigidity. A poured socket was formed on each end. The toggle was held 

 parallel to the handle by a quick release pin, the release for which was led up the handle. 

 Elastic cord was provided to snap the toggle into position perpendicular to the handle. To 

 assist in this function syntactic foam, with a density of 33 pounds per cubic foot, was asym- 

 metrically banded to the toggle to give a weight and buoyancy moment. Additional syntac- 

 tic material was banded to the toggle handle to reduce the in-water weight of the assembly. 

 Three I-section grips were attached along the handle to allow ALUMINAUT to handle the 

 toggle assembly. During the first lift attempt some of the syntactic foam worked loose, 

 causing the in-water center of gravity to change and making its suitability for the second 

 lift attempt questionable. 



A U-shaped steel hook was to be used for attaching the lift line to ALVIN's stern lift 

 fitting. The stern hook, depicted in figure 4, was specially designed with hinged dogs which 

 would lock automatically as the hook was positioned over ALVIN's frame bar. 



The toggle and stern hook were attached to two lengths of nylon line, sized 50 feet and 

 60 feet respectively, in order to equalize the strain during the lift. This two-part lifting bri- 

 dle was in turn attached to a ring in the lower end of the main lift line. 



52 



