Junior's hull and deck form the structural foundation of the vehicle, providing flotation, stability, propulsion mounting, equipment storage, and mounting locations for onboard systems. The current configuration combines two redesigned hydrodynamic pontoons with a lightweight enclosed deck.
Junior uses a symmetric catamaran configuration with two foam-filled pontoons. The pontoons were completely redesigned for the current vehicle with a more hydrodynamic shape and fiberglass-coated exterior. The revised geometry is intended to reduce resistance in the water while improving speed and cruising range.
The pontoons use stacked 1-inch pink insulation foam as their primary flotation structure. The completed pontoons measure 54" × 9.3" and were designed using Fusion 360.
Double T-slot rails run along the top and bottom of each pontoon, providing adjustable mounting locations for vehicle components. The rails allow equipment to be repositioned as the vehicle configuration changes and provide a way to adjust weight distribution without permanently modifying the hull.
The mounting system uses 2" × 0.5" aluminum two-slot flat channel and currently supports the deck structure and rear servo mounts. This modular approach allows Junior's configuration to evolve as additional systems are integrated.
Junior uses four Blue Robotics T200 thrusters, with two thrusters mounted in each propulsion pod. The pods use servo-controlled azimuthing to provide directional control and maneuverability on the water.
Each propulsion assembly uses a concentric shaft arrangement in which an inner rotating shaft transfers servo-driven motion within an outer structural housing. Thrust bearings provide low-friction rotation and reduce wear under load, while washdown collars secure the shaft assembly and limit axial movement. The propulsion assemblies use an enamel-coated 3D-printed mount to attach the servo to the pontoon rails.
The pontoon manufacturing process begins with water-jet cutting the individual foam pieces. The pieces are stacked and aligned using wooden dowels before being assembled into the final pontoon structure. Components are produced from the vehicle's CAD geometry to maintain the intended shape and dimensions.
The foam-filled assemblies are then reinforced with a fiberglass outer coating to provide structural protection and a sealed exterior. The completed hulls undergo sanding and finishing before receiving an enamel coating. This construction is designed to withstand repeated exposure to the marine environment while maintaining the flotation and structural characteristics required for operation.
The deck connects the two pontoons and provides an enclosed structure for Junior's electrical, computing, communications, and control equipment. The walls are constructed from lightweight aluminum honeycomb panels combined with fiberglass epoxy and carbon fiber reinforcement.
The honeycomb panels weigh less than 0.5 lb/ft², providing a lightweight structural solution while the composite layers increase strength and rigidity. The deck measures 28" × 24".
The deck interior is arranged around the physical dimensions and operating requirements of Junior's onboard equipment. Component placement considers center of mass, heat dissipation, wiring and cable routing, accessibility, and available space.
Equipment is secured using a combination of acrylic panels, 3D-printed mounts, screws, zip ties, and Velcro. The layout allows components to remain accessible for maintenance, replacement, and future modifications.
Three removable connector panels provide Junior's external power and signal connections. Separating the connectors into dedicated panels keeps interfaces organized and accessible while maintaining the deck's enclosed structure.
The panels accommodate a wide variety of connector types, including RJ-45 Ethernet connectors, USB-C, general-purpose multi-pin connectors, and various single-pin RF connectors. Their removable design allows connectors and interfaces to be changed as Junior's systems develop.
Three sets of clamps connect the deck to the pontoon mounting system. This provides a secure structural connection while allowing the deck and pontoons to be separated for maintenance, transportation, and modifications. The mounting system uses steel U-brackets and bolts to attach the PVC tubing to the deck material.
A large removable lid provides direct access to the equipment inside the deck enclosure. The lid is constructed from aluminum honeycomb material and secured using turn-to-open draw latches.
A rubber U-channel runs around the lid perimeter and is compressed by the latches to create a continuous seal. Additional sealing around connector panels, cable pass-throughs, fasteners, and other interfaces helps protect the internal systems from water exposure while allowing the enclosure to remain accessible for maintenance.
