design, called Crawldog (to distinguish its design purpose from the Crawlcat) can be developed 

 that would accommodate open coast conditions. This design would include a wider wheelbase 

 for increased stability, two large tracks instead of four, and a lower (submerged) pump. 2 The 

 Crawldog would offer the flexibility of moving within a borrow area (like a semifixed plant on a 

 fillet) or being transported to a different location altogether. Because the Crawldog would be 

 able to access much deeper water than a fixed or semifixed plant, it could increase the effective 

 storage area of a fillet to areas well offshore. In some instances, it may even be able to access an 

 ebb shoal directly. 



Potential concerns for the use of the Crawldog include the exposure of the discharge line to 

 breaking wave forces along the beachface and scour along (or burial of) the tracked wheels, 

 which may cause the Crawldog to become stuck, especially if it must remain in one place for a 

 long period (e.g. breakdown). Because of all the moving parts and long-term exposure of the 

 tracked wheels to the marine environment, saltwater corrosion may pose a maintenance problem. 



Typical Crawlcat designs (and probable Crawldog designs) include engine ratings of 350 to 

 550 kW (470 to 737 HP), pump capacities of 200 to 400 m 3 /hr (260 to 520 ydVhr), and 

 discharge pipe diameters ranging between 25 and 40 cm. Pumping distances depend on the 

 application and size of Crawlcat/Crawldog used. 



The following assumptions were used for cost analysis: 



a. Crawldog will be purchased for $2.75 million. 



b. Total Crawldog replacement will be needed in 15 years. 



c. Unit cost of operation will be $5.50/m 3 ($4.2 1/yd 3 ) (which does not include additional 

 booster pumps) (Bruun, in preparation). 



d. Pipeline costs (initial and replacement) are the same as for Alternative 2. 



e. Booster pumps and engine are the same as for Alternative 2. 



/ The 3/4-ton, 4- WD diesel truck is the same as for Alternative 2. 

 Crawldog costs are summarized in Table 18. 



Chapter 5 Bypassing Alternatives 63 



