that because of the uncertainty in sensor height and other factors, the 
Paroscientific sensors could not be used to measure setup’. Data from all 
sensors (four channels) were internally converted to a digital signal and 
transmitted as a serial data stream back to shore. Each instrument package was 
connected to a data collection system using four-conductor, double armor, 
lightweight cable. Each electronics package was hose-clamped to the support 
pipes and connected to the cable with four-pin Brantner underwater connectors. 
Except for the two seawardmost instruments (80 and 90), the current meter 
probes for the primary cross-shore array were mounted on a separate line of 
pipes placed 1.5 m northeast of the instrument package/pressure gauge pipe 
(Figure 6 in the main text). At the five innermost positions (10 to 50), the 
current meter stinger was mounted downward, 30 cm away from the mounting 
pipe. All other stingers were mounted upright. Some of the downward- 
mounted stingers were adjusted during the experiment to keep them either 
above the sand or in the water. 
A second data acquisition system was used to sample the analog output 
from the 10 current meters in the three subarrays. Five Scripps open frame 
electromagnetic current meters mounted upward were used in the Crest sub- 
array. Five Marsh-McBirney current meters with their sensors mounted 
downward were used in the trough subarray. A single upward-mounted open 
frame (54) completed the secondary three-element cross-shore subarray. Each 
of these current meters was wired back to the base of the duneline using seven- 
conductor double armor cable. The cables were wired into watertight 
"Hoffman" boxes. Power to the Hoffman boxes was isolated through the use 
of DC-to-DC converters as a preventative measure to reduce potential ground 
loops. 
Figure E2 shows the location of the cross-shore instruments, including the 
initial position of the current meters relative to the changing bottom and water 
surface. Note the nearness of some sensors to the water’s surface. This was 
taken into account when processing the data from these sensors and is 
discussed in the data analysis section that follows. 
Current meter orientations were determined with an underwater digital 
compass mounted on a long nonmagnetic pipe so that it was not affected by the 
steel in the sensor mount. For Marsh-McBirney current meters (Nos. 2101- 
2352) the compass was read with the meters aligned to the direction of -y flow 
of the sensor ball. For the open frame meters, the compass was read with the 
meter aligned in the direction of +x flow. At the time of the DELILAH 
experiment, it was believed that the pier axis was 70 deg east of true north, 
and the current meters were aligned relative to the pier. More recent measures 
have computed the pier orientation at 71.8 deg. Current meter orientations are 
listed in Table E1. 
J Personal Communication, 29 April 1997, Dr. Edward Thornton, Dept of Oceanography, Naval Postgraduate School, 
Monterey CA 
Appendix E Stationary Instrument Data 
