Date of Award

4-27-2026

Degree Type

Capstone Project

First Advisor

Professor Bahram Nassersharif

Abstract

This project presents the design, development, and preliminary validation of a scalable variable ballast system for an Unmanned Underwater Vehicle (UUV), conducted in collaboration with the Naval Undersea Warfare Center (NUWC). The objective of the system is to enable controlled buoyancy adjustment, allowing the vehicle to submerge, maintain depth, and resurface efficiently without reliance on continuous propulsion. Existing small and mid-sized UUVs often utilize propulsion systems, reducing operational flexibility and efficiency. The project addresses these limitations through a simplified and adaptable ballast system design.

The system consists of a central ballast tank that passively floods through dedicated inlet openings, with solenoid-controlled pathways facilitating efficient water intake. Buoyancy control is achieved through a compressed air system that displaces water from the ballast tank, enabling resurfacing. A secondary trim system, composed of two sealed tanks and a peristaltic pump, allows for controlled redistribution of water to adjust vehicle pitch and improve stability. A functional prototype was fabricated and tested to evaluate system performance, focusing on subsystem functionality and structural integrity. Testing confirmed that the ballast tank and hull maintained a leak-proof seal under extended submersion conditions, demonstrating reliable containment of both water and internal components. The solenoid-based intake system successfully enabled controlled water ingress into the ballast tank, while the compressed air system effectively expelled water, validating the system’s ability to perform both submerging and resurfacing operations. These results confirm that the core components of the ballast system operate as intended.

While full system integration testing is ongoing, the current results demonstrate the feasibility and reliability of the design. The system meets key project objectives and provides a foundation for future development. Recommended future work includes integrated system testing under dynamic conditions, implementation of automated control systems, and validation at greater depths and pressures. This work contributes to defense and research environments.

Comments

Team Name: Team 4

Company Sponsor: Naval Undersea Warfare Center

Sponsor Representative: Scott Veitch

Document Reference: URI-MCE-2026-FDR-004

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