Mechanical Load Gauge 



A mechanical load gauge was installed on each of four windward 

 anchor chains (Figure 4). The load gauges produce scratches on brass 

 disks that rotate as the scratch is being made. After retrieving the 

 disks at the end of the field season the scratches were measured using a 

 microscope. This provided estimates of the largest loads but did not 

 give the load- time history. The gauges were designed for a maximum load 

 of 5000 lbs (22250 N) . They were calibrated in the lab and showed a 

 linear relationship between the load and the length of the scratch up to 



22250 N. 



The gauges were deployed September 24 - November 12, 1981 and 

 June 15 - November 15, 1982. The largest measured loads were much 

 smaller than the design load of 22250 N, and therefore, the resolution 

 of the scratches was sometimes difficult. The maximum estimated loads 

 (N ± 20 percent) for gauges 1 to 4 for 1981 and 1982 respectively were: 

 12 3 4 



1981 4900 3400 3700 3900 



1982 - 5900 4400 5400 



These estimates compare well with the maximum loads measured in 1982 

 with the electronic load cells: 5400 N at the central anchor chain 

 between gauges 2 and 3, and 6300 N at the corner anchor chain beside 

 gauge 4. These loads were probably induced by characteristic wave 

 heights of 65 cm or less. 



IQO 



