PRISM 2 Rebreather Overview
The Prism 2 is a fully enclosed circuit rebreather specifically designed for underwater exploration in open oceans, caves, or shipwrecks. This versatile unit can be operated electronically or manually, allowing divers to select their preferred method for maintaining loop PPO2 levels.
Features of the Prism 2
The unit offers the option of front-mounted counterlungs, which, in conjunction with a rear-mounted radial scrubber, ensures effortless breathing with minimal resistance and low hydrostatic pressure. Notably, the Prism 2 has been subjected to ANSTI testing at depths of 100 meters and boasts the lowest work of breathing (WOB) among mixed gas closed-circuit rebreathers available on the market. The standard configuration includes an electronic secondary control, primary LED displays, and a backplate/wing assembly, making it ready for immediate use upon purchase, with tanks and valves sold separately.
Back-Mounted Counterlungs
The back-mounted counterlungs are strategically positioned behind the diver, freeing the chest area for additional tanks and accessories. This design enhances streamlining, reduces drag, and improves horizontal trim.
The counterlungs feature a two-piece bag design that optimizes WOB performance and allows for the easy removal of the internal lung for cleaning or replacement. The ADV upstream valve design is both reliable and resistant to free flow, which is crucial for preserving valuable diluent gas. All gas delivery systems on the Prism 2 offer both automatic and manual functionality. Water trapping T-pieces prevent excess water from entering the breathing loop, while streamlined hose fittings ensure that low-pressure hoses remain close to the diver, minimizing overhead interference. The machined dilution (DIL) and oxygen (O2) manual addition valve controls provide a robust and dependable design, with offboard gas connections available on both sides.
Rear-Mounted Radial Scrubber
The Prism 2 features a user-packed radial CO2 scrubber weighing 5.5 pounds, designed to provide optimal duration, insulation, and ease of breathing. The scrubber canister is mounted vertically on the backplate, nestled between twin supply cylinders for oxygen and diluent. Constructed from engineered thermoplastic, the clear scrubber bucket is a unique Hollis design that ensures proper installation and packing while providing visual confirmation of loop integrity.
High-Performance DSV and BOV
Every Prism 2 comes equipped with a standard Dive Surface Valve (DSV), with an optional Bailout Valve (BOV) available. The BOV features a high-performance regulator valve, is lightweight, and can be directly attached to the Prism 2 as a replacement for the DSV. Many professionals consider the Prism 2 BOV a fundamental safety feature and it meets the training requirements for technical rebreather courses.
Electronics and Displays
The electronics, sensors, and batteries are housed in the electronics head assembly located at the top of the scrubber. Supply hoses route over the diver’s shoulders into the counterlungs. An analog LED primary display provides quick access to unit performance, including status and alarm indicators, while an independent digital OLED secondary display offers verification of the unit’s performance.
Comprehensive Features
- **Optimal WOB**: 1.57 J/L at 40 meters using AIR as diluent
- **Unit Weight**: Approximately 47 lbs when fully charged and in standard configuration
- **Split Counterlungs**: Allow for separate inhale and exhale counterlungs for high workloads
- **Counterlung Drains**: Designed for easy water removal during dives
- **External Gas Lines**: Prevent leaks from affecting PPO2 levels
- **Automatic Diluent Addition Valve**: Adds diluent during descent or when loop volume is low
- **Manual Diluent Addition Valve**: For on-board or off-board diluent flushing
- **Compatible Gases**: Air, Trimix, and Heliox
- **Manual Oxygen Addition Valve**: Allows for manual control of oxygen PPO2
- **Integrated Harness and BC or Backplate**: Ensures the Prism 2 is ready for immediate diving
- **High-Performance Open Circuit Bailout Valve Option**
- **Customizable Wings and Harness Options**
- **Flexible Gas Management**: Accepts 2L and 3L cylinders with the supplied tank band
- **Eye-Level LED Primary Display**: Facilitates easy monitoring of system status
- **PPO2 Monitoring**: Continuous display from three sensors ensures real-time monitoring
- **Multi-Gas Support**: Enables diluent switching and multi-gas dive planning
- **Quick OC Bailout Activation**: Simple two-button push for rapid transition to bailout support
- **CNS Tracking**: Monitors real-time oxygen exposure
- **Software Update Capability**: Via web interface
- **Dive Log Download Feature**
- **Stainless Steel Stand Included**
Technical Specifications
- **Dimensions**: Length - 21 in (53.3 cm), Width - 17 in (43.2 cm), Depth - 9 in (22.9 cm)
- **Buoyancy**: Neutral
- **Weight**: Approximately 47 lbs with tanks
- **Scrubber Flow Design**: Radial
- **Counterlungs**: Front Mount 3.5L / Back Mount 4.0L
- **PO2 Set Points**: Adjustable (0.7, 1.0, 1.2, 1.3, 1.4)
- **O2 Sensors**: 3 galvanic
- **Sensor Life**: 12 months in air or 100 hours of dive time
- **Heads-Up Display**: Yes, powered by a 9V battery with sequential LED
- **Handset**: Yes, (Shearwater Petrel), powered by a Lithium cell
- **Battery Types**: 9-volt Alkaline / 3.6V Lithium cell
- **Battery Life**: 40 hours
- **Automatic Setpoint Switch**: Yes
- **Integrated Weight System**: Yes (optional)
- **Scrubber Duration**:
- 190 min (0.5%, SEV CO2) at 8-12 °C, 3.0 L/min CO2, 18 fsw/6 msw
- 190 min (0.5%, SEV CO2) at 8-12 °C, 1.6 L/min CO2, 131 fsw/40 msw
- 215 min (0.5%, SEV CO2) at 8-12 °C, 1.6 L/min CO2, 330 fsw/100 msw
This comprehensive overview highlights the advanced features and technical specifications of the Prism 2, ensuring that divers are well-equipped for a variety of underwater adventures.
