N251-028 TITLE: Alternative Means of Deploying Shot Line

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Sustainment

OBJECTIVE: Develop an accurate, reliable methodology of deploying shot line between two ships for underway replenishment (UNREP) operations.

DESCRIPTION: The U.S. Navy’s DDG-51 Class Destroyers are typically at sea for extended periods. To sustain the ships, they are frequently resupplied at sea via UNREP. During UNREPs, shot lines are deployed to start the process of deploying a service line to pull the fuel hose to the receiving ship. The current method for deploying shot line has changed little since the Age of Sail. The shot line is a lightweight line attached to a projectile that is fired from a rifle powered by chemical propellant. Once the shot line is received on the other ship, it is hand-pulled by two to three sailors to bring a larger rope across and eventually the span line wire rope. Since the shot line is manually fired, it is an inaccurate process that sometimes requires multiple attempts before the connection can be established. If the shot line connection does not occur, the ship’s UNREP evolution may be at risk. The current process of deploying shot line is time consuming, inaccurate, and presents a potential hazard to personnel on the receiving ship.

Shot line is deployed to the receiving ship via a manually fired gun. The equipment used has been improved over time, but still has the basic drawbacks of using a shoulder fired gun. Manually aiming shot line is difficult, particularly at high sea states, and prone to error. The development of an alternative means of deploying shot line to meet Navy needs must overcome several technical challenges. First, the ships are approximately 200 feet apart. The line must be shot from one moving platform to another moving platform, relying on the proficiency of the gunner’s mate in sometimes challenging environmental conditions. Next, the device must be able to function during conditions up to Sea State 5 on the Beaufort scale. Environmental conditions include such hazards as rain, sea spray, and fog, all of which affect visibility and thus the ability to accurately deploy the shot line. While the legacy process has been safe under optimal conditions, it still has some risk.

Recent technological advancements in smart targeting systems have potential to improve the deployment of shot line. However, such systems have not been adequately demonstrated in the commercial sector to meet Navy requirements. Especially since the system must be compact, but also able to operate in rough weather. R&D is needed to improve and innovate these technologies, so they are fit for Navy use.

An alternative means of deploying shot line must be inherently safe under all conditions that underway ships would attempt UNREP. Any device utilized in a developed methodology should be man-portable and compact for storage and transport.

PHASE I: Develop a concept for an improved method for deploying shot line that meets the requirements above. Demonstrate the feasibility of the concept in meeting Navy needs and establish that the concept can be developed into a useful product for the Navy. Feasibility will be established via computer modeling or other means deemed appropriate. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Develop and deliver a prototype shot line deployment system. The prototype will be evaluated to determine capability in meeting the performance goals defined in the Phase II Statement of Work. Product performance will be demonstrated through evaluation, modeling, and demonstration over the required range of parameters. An extended test in a maritime environment will be used to refine the prototype into a design that meets Navy requirements. Prepare a Phase III manufacturing and development plan to transition the alternative means of deploying shot line to Navy use.

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the alternative method of deploying shot line to Navy use. Develop installation, maintenance, and operations manuals for shot line deployment to support the transition to the fleet. There are many potential commercial applications for an alternate means of deploying shot line in inimical conditions. Notable examples include such varied fields as bridge construction, rapid deployment of bear bags, and, launching rescue lines for people in the water.

The service industry supporting off shore platforms will benefit from developments under this topics.

REFERENCES:

1. Kourani, Ahmad and Daher, Naseem. "Marine Locomotion: A Tethered UAV-Buoy System with Surge Velocity Control." Arxiv, November 2021. https://arxiv.org/pdf/2107.14662.pdf

2. Bolognini, M. and Fagiano, L. "LiDAR-Based Navigation of Tethered Drone Formations in an Unknown Environment." Arxiv, July 2017. https://arxiv.org/pdf/2003.12981.pdf

3. Horsdal, E. "The Swinging Counterweight Trebuchet: On Scaling and Optimization." Arxiv, 2023. https://arxiv.org/abs/2303.01306

KEYWORDS: Shot Line; Span Line Deployment; Underway Replenishment; UNREP; Projectile Deployment; Service Line

TPOC 1: Devin Burke
(202-486-8482
Email: [email protected]

TPOC 2: James Wegner
(202) 781-199
Email: [email protected]

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