Surf crawlers made from mid-sized excavators are currently operating in Nome.  They can have buckets that range from 1/4m³ to 1m³ with smaller sizes being the most common.  Production rates of up to 200m³/day can be achieved if round the clock operations can be sustained.  Since the main component of the dredge is a mid-sized production excavator, initial costs will be low at $100,000 to $500,000.  Since the spread is driving on the bottom and not floating, the mobility is limited to near shore operations where the water is shallow. The tracks and elevating framework can be under water but the cab, engine and equipment must be kept above any wave action.  Again, sporadic loading of the wash plant can be problematic. Mobility risk comes from unknown seabed conditions without any subsea cameras or sonar surveillance.