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 Shearwater Research Petrel Dive Computer (V11)

All Petrel Models In-stock for Immediate Shipment

The Petrel Dive Computer from Shearwater Research of Canada incorporates a powerful feature set, easy to understand menus, easy to read full color display, Bluetooth wireless upload/download and a robust compact case. The Petrel has been designed to accept any type of AA size battery including alkaline, lithium and rechargeables. Out of the box, both Petrel models include open-circuit and closed-circuit Air, Nitrox and Trimix mixed gas functionality. The Petrel-EXT adds a Fischer 103 I/O port used for external PO2 monitoring of up to three oxygen sensors in a rebreather loop.

New features for V11 include a user configurable center row information display and support for external PO2 with optional 'giant' font, see the V11 Release Notes for details.

Both Petrels offer a screen display utilizing a new generation of low-power consumption, high resolution QVGA, full color LCD display. The display will automatically adjust intensity based on available light to make the display easily readable whether on the surface in sunlight, in open water or in a cave. The full color display is used to convey additional meaning with the information being displayed. When information is yellow or red, it calls the divers attention to an unusual value or problem. With the large color display, a buddy or instructor can glance at your Petrel to determine your status.

Features of the Petrel Dive Computer

The Petrel is a full decompression dive computer incorporating the Bühlmann ZHL-16C algorithm, with user configurable Gradient Factors (GF). Gradient Factors allow the diver unique and individual control of their dive computer decompression calculations. Also new with the Petrel is a richly featured 'gauge mode' configuration. The included CCR mode for rebreathers provides the ability to perform constant PO2 set point calculations for deco. An optional PIN upgrade to the Varying Permeability Model (VPM-B and VPM-B/GFS) decompressionalgorithm is now available. During a decompression dive, the Petrel provides complete information displays of all required stop times. The Petrel can provide time-to-surface based on "look ahead" at planned gas switches. Multiple gas definition presets are supported with any combination of oxygen, nitrogen and helium. The Petrel will NOT "lockout" after a missed stop or ascent rate violation.

Included with every Petrel from Dive Gear Express are two elastic straps with buckles, 1.5V alkaline AA battery already installed (ready to dive out of the box!), bungee mount adapter (for those who prefer bungee mounting to buckle straps), USB Bluetooth adapter, mini-CD with Petrel Manual (PDF) and printed Quick Start Guide with instructions for downloading software from the Shearwater Research website. The Petrel also includes a screen protector already installed to help prevent scratches of the display face. The Petrel-EXT model adds the Fischer 103 connector, cap, and small bottle of mineral oil. The software includes a complete dive log manager, compatible with both MS Windows and MAC OS X. The dive log manager supports log downloads and firmware updates via the Bluetooth wireless interface of the Petrel. An optional VPM-B unlock code enables using the Varying Permeability Model (VPM-B and VPM-B/GFS) algorithm for calculating decompression.

Gradient Factors

Gradient factors are the most popular method of implementing user selectable decompression profiles in technical dive computers. Gradient factors allow the diver some control of the initial stop depths and times of required decompression dives. If you aren't familiar with theory and practice of gradient factors, we suggest taking a few minutes with GRADIENT FACTORS by Matti Anttila, Ph.D. Originally published in 2007 for the IANTD Tech Diving Encyclopedia, this informative article gives excellent insight into understanding decompression theory and gradient factors.

The Varying Permeability Model (VPM) is a decompression algorithm that attempts to predict the behavior of bubbles within the human body during decompression. Compared to typical Bühlmann profiles, VPM dive profiles often have deeper initial stops that are believed to reduce bubble formation, along with reduced time at shallow depths. VPM-B (a version that includes adjustments for Boyles Law effects) is popular among the technical diving community for use in calculating dive tables with required stops. The algorithm was initially developed by David Yount based on laboratory observations of bubbles under pressure and coded into Fortran by Erik Baker. Shearwater Research has implemented VPM-B according to the original Erik Baker Fortran specification. VPM-B allows a conservatism factor to be adjusted over a range of 0 (least conservative) to +5 (most conservative), the default is +3. In addition to implementing the Baker reference version, Shearwater Research has added an enhanced version because some divers believe the reduced shallow depth stop times may be too short for lengthy VPM-B profiles. The Gradient Factor Surfacing (GFS) option adds conservatism to the shallow stops on dives with significant decompression requirements (dives with total required deco exceeding an hour.) The GFS option is a hybrid that automatically chooses the decompression ceiling from the more conservative of the VPM-B profile and a Bühlmann ZHL-16C profile. For the Bühlmann profile a single gradient factor is used, adjustable over a range of 70% (most conservative) to 99% (least conservative), the default is 90%.