There are also certain unknowns associated with the first application of a new technology (such 

 as potential design flaws and construction imperfections) that may make it less attractive. 

 Though more mobile than a semi-fixed plant, the relative mobility of the larger Crawldog (i.e., 

 compared to a floating plant or Punaise) would probably limit multiple inlet use. 



The Punaise, which has the lowest first cost (mobilization/demobilization), has the fourth- 

 highest annual cost, very near the Crawldog alternative. The Dutch experience over the past 

 5 years indicates that it is not a new technology (although it has not been used in the United 

 States). Punaise, somewhat like a floating plant, also offers the intriguing possibility of use at 

 multiple inlets. Mobilization and demobilization costs could be spread over several sites while 

 the Punaise performs bypassing as needed/desired on a site-by-site basis. Also similar to the 

 annual cycles described for the floating plant, the Punaise could pump larger quantities of sand 

 over a larger time interval (2 or 3 years as opposed to 1 year) and thus reduce the impact of 

 engineering and design, and contingencies. Several questions remain to be answered regarding 

 the Punaise including running the umbilical through the surf zone and the stability of the Punaise 

 to remain on the bottom during high wave conditions. Even with a modified design, the Punaise 

 will not capture transport volumes moving shoreward of its location (currently around 6 m), 

 which may prove to limit bypassing effectiveness. 



Chapter 5 Bypassing Alternatives 71 



