Date of Award
2025
Degree Type
Thesis
Degree Name
Master of Science in Ocean Engineering
Department
Ocean Engineering
First Advisor
Stephen Licht
Abstract
Mesophotic and deep-sea gorgonian octocorals in the Gulf of Mexico were significantly damaged following the Deepwater Horizon oil spill, prompting a major federal investment in developing restoration techniques for these fragile, slow-growing communities. Asexual, in-situ coral propagation offers a biologically viable path for restoration at depth. However, current ROV systems are not optimized for the delicate, fine-scale interactions required to perform this process reliably. The objective of this research was to design, prototype, and evaluate a ROV-mountable toolset capable of preparing octocoral fragments for potting in epoxy substrate, with the additional goal of integrating the toolset into URI’s Coral Carousel -- a deep-water substrate insertion system developed by Bales.
This work progressed through iterative development of an Axial Skeleton Isolation System (AXIS) designed to remove coenenchyme from coral mimics in realistic underwater conditions. Three rotary-brush systems and three mechanical iris mechanisms were fabricated using 3-D printed components, off-the-shelf materials, and a Blue Robotics M200 thruster for actuation. Ballistic-gel coral mimics representing multiple species were prepared and tested in controlled experiments. Quantitative and Qualitative metrics -- including cleaning efficacy, axial-skeleton preservation, prototype controllability, and compatibility with the Coral Carousel -- were recorded across all prototypes.
The rotary-brush prototypes were capable of removing the ballistic-gel tissue layer, but all suffered from major constraints: limited control of flexible coral analogs, frequent skeletal damage, high reliance on dual-point stabilization, and poor compatibility with Coral Carousel geometry. In contrast, the mechanical iris mechanism provided uniform circumferential stripping, required no additional stabilization, preserved the axial skeleton in all tests, and integrated cleanly into the carousel. The platform-mounted iris consistently achieved complete, repeatable removal of the tissue mimic and the station-mounted iris represents the most viable approach for ROV-based fragment preparation.
Recommended Citation
Bevilacqua, Joe, "DEVELOP A CROSS-PLATFORM TOOLSET FOR IN SITU DEEP-SEA CORAL PROPAGATION" (2025). Open Access Master's Theses. Paper 2681.
https://digitalcommons.uri.edu/theses/2681
Appendix A - Prototype Performance Testing
Appendix B - Bill of Materials.pdf (76 kB)
Appendix B - Bill of Materials