The tire retainer used in the PT-1 module is shown in Figures 4 and 7. In 

 the case of the PT-2 module, the retainer was a tire casing that was held in 

 place by a 1.9-centimeter threaded steel rod extending through the telephone 

 pole and casing. 



Standard marine steel-pile pipes were utilized as buoyancy chambers and 

 stiffeners in the PT-1 module; they were 12.2 meters long and 41 centimeters 

 in diameter, with a wall thickness of 0.71 centimeter. Scrap telephone poles 

 were used for the PT-2 module; they were 12.2 meters long with a diameter of 

 33 centimeters at the butt end and 23 centimeters at the tip. 



Truck tires ranging in size from 9.00-18 to 10.00-20, with an average 

 diameter of 102 centimeters were used for PT-1. Car tires with rim sizes 

 ranging from 32 to 38 centimeters were used for PT-2; the average diameter was 

 about 65 centimeters. 



A three-ply conveyor belt strip, 14 centimeters wide and 1.3 centimeters 



thick, was used as the binding material; this had a rated breaking strength of 



7900 kilograms. A five-hole bolted connection (Figs. 8 and 9) was used to tie 

 the belt into continuous loops . 





1 











-f • 





Figure 8. Breakwater and mooring-system components, 



15 



