buoyant. Being more tightly coupled, each stringer module is stiffer and better 

 retains an overall rectangular shape. A desirable overall floating breakwater 

 shape is more easily achieved using this tire maze design. 



Figure 11 shows details of the car tire maze stringers for the PGYM-2 

 design. Again, each stringer is made from tires assembled in a Goodyear modular 

 arrangement. Two modules were joined at their ends to make one stringer for the 

 maze. These car tire stringers were joined at their ends to truck tires on the 

 tire-cladded tubes using rubber belting. Like the PGYM-1 design, the principal 

 direction of wave advance is directed towards the openings in the tires (see 

 Figure 12) . 



All subassemblies were fabricated at the marina and consisted of one tire- 

 clad tube with attached tire maze and short loosely assembled joining belts 

 connected to tires on the side later to be joined to the tire-clad tube of 

 the next subassembly. Large-diameter truck tires were belted outside at the 

 ends of the pipe to the first tire on the pipe. These tires provide some 

 measure of damage protection should a boat come in contact with the breakwater 

 in the regions of steel pipe end exposure. Figure 13 shows the short steel tire 

 retaining lugs sandwiched between two end tires. 



A subassembly, with mooring lines connected, was lifted with a travelling 

 boat cradle crane by cabling around the tubes (Figure 14) and moved to a 

 position over the launching well. Since the tire maze was assembled with the 

 foam in the top of all tires, the tires came up on the correct side as the 

 assembly was lowered into the water (see Figure 15). As the assembly was eased 

 out of the launching well, a 16-ft.~long boat with outboard drive was lashed to 

 each side. These boats were used to move the subassemblies approximately 3/4 

 miles to the installation area (see Figure 16). Steering of the assembly was 

 accomplished primarily by increasing motor r.p.m. on one side or the other. 



On-site the front mooring line was attached and then the inside boat was 

 decoupled and the remaining boat was shifted into reverse gear. This brought 

 the subassembly next to the already installed section where it could quickly be 

 attached at front and back. 



It was necessary to work in the water to complete connection of the 

 section. This was best accomplished by two people, one sitting on the 

 tire-cladded tube handling the tools and hardware with the other in the water 

 fastening the binding belts (see Figure 17). 



The site was instrumented using a newly developed real-time wave height, 

 period and direction measuring device. This instrument was placed at the center 

 and fore of the breakwater so as to be able to monitor the incoming waves. A 

 tripod mounted wire wavestaff gauge was placed aft of the breakwater. This 

 instrument was moved from one design configuration to another as required. A 

 long, slim wire wavestaff gauge, which could be inserted down through an opening 

 between tires to rest on the bottom while being hand held at the top, was also 

 used to obtain data. 



Figure 18 shows the installation during late November. A public boating 

 launching ramp is located out of view at the lower left with access between the 

 stone groin and the concrete wall shown in the picture. 



50 



