The objective of this project is to assess the capabilities, towing capacity of a low profile, small wheel base surf zone crawler whose purpose is a sensor carrier and tow-tractor. The crawler will operate across mixed terrain and sea states while maintaining predetermined mapping patterns. Coverage and relocation accuracies will be determined at five diverse environments including sand, gravel, vegetated, various slopes and soft ground both on land and in the surf. Demonstrations will be performed at two sites representing common yet environmental extremes such as surf and tidal flats. The reduced logistical footprint will be demonstrated in terms of set up, sustainability, and recovery. Coverage, coverage accuracy, coverage rates and cost of operations will be recorded. 

Technology Description

The man-portable modular crawler is based on the C-2i developed Sea Otter system. The low-profile design allows the system to operate in the boundary layer minimizing hydrodynamic drag. A modular design permits varying the footprint area and draw-bar pull to match the tow sled drag to the environment A lighter, low hydrodynamic lift trailer using un-powered tracked rolling friction rather than the present sled design will be developed. The system is designed to be assembled at the site swapping out transmissions to match the conditions. and minimizing logistical burden. C-2i's navigation algorithms will be used to follow a pre-planned path and an optional radio frequency (RF) linked buoy will permit manual control. The Flex-Em is being redesigned to minimize the drag and weight profile. Other sensor systems will also be evaluated. Back-up algorithms are being developed to ease operation in cluttered environments.


The man-portable system has a smaller logistical footprint that minimizes setup costs. It permits transport across environmentally sensitive or difficult access areas without the need for roadways. The smaller footprint also makes for simpler recovery. The minimal environmental impact makes permitting it easier. The modular nature of the tractor sled combination allows a greater mission and payload flexibility to include additional instrumentation and mitigation systems. The low ground pressure of the Sea Otter surf zone crawler (OSZC)/Flex-EM allows surveying mud flats, dredge fill, tailings ponds, marshes and swamp regions that are dangerous to human transit or heavier equipment. The small wheel base results in greater maneuverability to operate in cluttered environments. The lower capital and modular replacement will result in lower operating expense.

  • Wheel Based Surf Zone Crawler ,

  • Sea Otter System ,

  • Field Testing