A method for retrieving a mobile platform from inside a tank having a hatch and at least partially filled with an energetic substance, the method comprising:
- configuring a retrieval carrier to have at least an intermediate span and an attachment end, wherein a majority of a cross-sectional area of the intermediate span includes a braided synthetic fiber rope having a porosity of at least ten percent, wherein the braided synthetic fiber rope has an elastic compressibility sufficient to reduce the porosity of the braided synthetic fiber rope by at least fifty percent, wherein the intermediate span does not have a fluid tight passage enabling fluid communication between a location outside of the tank and the mobile platform;
- configuring the mobile platform to have at least:
- at least one enclosure and at least one propulsion system positioned at least partially inside the at least one enclosure;
- configuring a retrieval assembly to have at least:
- a retrieval frame, an energetic substance extractor, and a retrieval winch, wherein the retrieval frame supports the retrieval carrier, the energetic substance extractor is positioned between the retrieval frame and the mobile platform, and the retrieval winch is connected to the retrieval carrier;
- configuring the energetic substance extractor to have at least:
- a plurality of opposing surfaces defining a passage, the passage being sized to cause the opposing surfaces to have rolling contact with and compress the intermediate span of the retrieval carrier in the passage;
- moving the mobile platform in the tank using the at least one propulsion system while the mobile platform is submerged in a liquid energetic substance;
- positioning at least the energetic substance extractor of the retrieval assembly adjacent to the hatch;
- retrieving the mobile platform from inside the tank using the retrieval carrier, wherein the retrieval carrier is connected to the mobile platform by the attachment end, the retrieving done by at least:
- operating the retrieval winch to pull the intermediate span of the retrieval carrier toward the retrieval winch, and
- passing the intermediate span of the retrieval carrier through the passage while the intermediate span of the retrieval carrier is being pulled to the retrieval winch,
- wherein the intermediate span of the retrieval carrier passing through the passage applies a torque at the rolling contact with the plurality of the opposing surfaces, and wherein the applied torque rotates the opposing surfaces, and
- wherein the intermediate span of the retrieval carrier was submerged in the liquid energetic substance and retains a residue of the liquid energetic substance upon entering the passage;
- and
- compressing the intermediate span of the retrieval carrier between the plurality of the opposing surfaces, wherein the compression extracts from the intermediate span in the passage a majority of the residue of the liquid energetic substance retained by the intermediate span of the retrieval carrier upon entering the passage.