Hydrohold - senior capstone

Hydrohold - senior capstone

2.009 Product Engineering Processes

2.009 Product Engineering Processes

Product Overview

Rapid-deployment rescue diving safety device that securely connects a diver to a drowning victim during a rescue mission, freeing the diver's hands for the critical operations that save lives.

Hydrohold is Patent Pending

  • Product Specifications

    Product Specifications

    Load Rating: 800 lb
    Maximum Depth: 60 ft
    Weight: 5 lb
    Dimensions: 5.5" x 4.5" x 7.5"
    Strap Length: 4.5 ft
    Unit Cost: $80

  • Dual-Gate Carabiner

    Specialized carabiner clasps onto D-ring on the diver’s gear in a simple and fast motion.
    Custom two-gate design provides extra protection against accidental unclasping.

  • Spooling Mechanism

    Strap extends and retracts from a custom housing.
    Knob is turned to engage a ratcheting mechanism, preventing extension of the strap.

  • Universal Attachment

    Hydrohold attaches to straps on the diver’s existing gear.
    In an emergency, flight tags can be pulled to quickly release Hydrohold from the diver’s gear.

Safe​

Reliable​

Streamlined​

Skip to 2:45:40 for Hydrohold Showcase

Throughout the semester, we worked closely with Massachusetts Fire and State Police Departments, learning from rescue divers firsthand to develop an alpha prototype of Hydrohold.

We’ve developed a simple and safe product that a rescue diver can use even with their bulky gloves and limited visibility underwater.

Diver Testimonials

Shoutout to Cambridge Fire Rescue Dive Team!

Presented product prototypes to dive teams

"This product has great value, and nothing like this exists on the market for ​rescue diving."​​

Lt. Paul Morrison​
Cambridge Fire Department​

"This could be applied to situations outside of just rescue diving, such as recovery dives and other underwater missions."​​​

Tr. Robert MacAleese​
Mass. State Police Marine Unit​

Trying on dive gear (BCD, oxygen tank…)

30+ User Interviews

Testing

Assembly

Carabiner: Design and Fabrication

Throughout this process, most of my contributions were focused on the clasp subsystem. In a group of four, we iterated through many carabiner designs built around the diver’s experience. Over just a few weeks, we down-selected to a simple, sleek design that met the main user needs. The large form factor makes it easy to handle underwater while wearing bulky gloves, and the dual-gate mechanism adds an extra layer of security against accidentally coming decoupled.

Iteration

Team & Reflections

  • PINK TEAM

    Alena Hu
    Aleksandra Kaminska
    Amanda Medina
    Erin Hovendon
    Giuliana Pertuz
    Hannah E. Rose
    Haris Imamovic
    Iva Goel
    Joel Santiago Baretti
    Josh Randolph
    Kathy Zhao
    Maryanna Betterly
    Nicholas Cerone
    Olivia Chen
    Olivia Rivera
    Rian Evans
    Thomas Larsen

  • Instructors and Lab Staff:
    Daniel Braunstein, Dave Barrett, Atissa Banuazizi, Peko Hosoi, Josh Wiesman, Bill Cormier, Andy Macinnis, Scott Spence

    User Testers:
    Lt. Paul Morrison, Cambridge Fire Department
    Ed O’Brien, Woods Hole Oceanographic Institute
    Tr. Robert Macaleese, Massachusetts State Police
    Mary Beth DiGenova
    (as of 12/9/2025)

  • Throughout this semester, I feel my design process has greatly matured. The grounding philosophy of this product, "Simple and Safe", has shaped my outlook on product design. Simplicity is key for a product, and a great product will only present features that directly address a user need. No gimmicks, no gadgets, pure function, and nice cosmetic form. I also feel I have a much deeper understanding of the role of frequent user visits, testing, and feedback. Interacting directly with the end-user every step of the product design process helped us to quickly refine our scope and truly understand the needs of our users. In the future, I will make sure to keep great relationships with the users of my products, and ensure our solution works for them in a uniquely personal way.

  • As a team, I also noticed some notable trends for our growth. I noticed we progressively got better at integrating feedback quicker and prototyping more rapidly. Over time, we had many power structures, like subteams and subteam leads, but their importance and use blurred and morphed over time. Personally, I drifted between subteams, stayed on clasp for a while, and then switched to renderings and graphic design for our brochure. It showed me how productive our team had become at parallelizing tasks, which helped us converge on final designs quicker and streamlined decisions and ownership. I believe one of our biggest strengths was our ability to make decisions in the face of uncertainty. Especially toward the end of the semester, our team learned how to best come to concensus about important system-wide decisions, choose final prototypes with multiple functional solutions, and deciding which late-stage feedback to consider or ignore for now. This capability allowed us to produce two samples of our final prototype, with all subteams uniquely proud of their contributions to our product.

  • Reach out to me at thlarsen52@gmail.com to discuss.

  • After 2.009, we kept the project going by incorporating as Hydrohold Inc. and joining MIT Sandbox. We’re now continuing to improve the design and figure out what it takes to turn it into a real product.

Next

Soot Sprite (2.008)