An apparatus, a system, and method for generating underwater navigational information includes receiving data from a user, obtaining inertial data from inertial sensors, producing an estimation of a propulsion power by the user at a predetermined points of time by calculations at least partly based on the obtained inertial data, a hydrodynamic coefficient is calculated for the user at least partly based on the input data by the user, a velocity of the user is calculated at least partly on a basis of the estimated propulsion power and the determined hydrodynamic coefficient, heading information of the user at the predetermined points of time is calculated from the obtained inertial data, the calculated velocity information is combined with the calculated heading information at corresponding points of time and navigational information is generated.

An apparatus, a system, and method for generating underwater navigational information includes receiving data from a user, obtaining inertial data from inertial sensors, producing an estimation of a propulsion power by the user at a predetermined points of time by calculations at least partly based on the obtained inertial data, a hydrodynamic coefficient is calculated for the user at least partly based on the input data by the user, a velocity of the user is calculated at least partly on a basis of the estimated propulsion power and the determined hydrodynamic coefficient, heading information of the user at the predetermined points of time is calculated from the obtained inertial data, the calculated velocity information is combined with the calculated heading information at corresponding points of time and navigational information is generated.

An underwater diving light includes efficient cooling of LEDs and other internal electronics by heat transfer to ambient water. The water is in contact with a metallic face plate or puck that conducts heat via contiguous metal from an LED circuit board or LED face plate. Ambient water can enter the assembly to spaces between the face plate and an intermediary plate at the front of a housing to efficiently cool the LEDs and associated electronics. In a high-output form the light can emit 8000 lumens, and in this embodiment the battery is cooled by ambient water. The face plate or puck is interchangeable, for different lighting characteristics.

A first flipper has a base, a deformable fin connected to the base, and a first spreader that imposes a first force on the fin that causes the fin to spread in response to relative movement between the first spreader and the fin caused by a first longitudinal deflection of the fin relative to the base. A second flipper has a fin and a foot coupling portion connectable to a foot holding portion of a boot to couple a foot in the foot holding portion to the flipper. A first system includes the flipper and the boot. Methods of using the flippers, the boot, and the system are also disclosed.

A first flipper has a base, a deformable fin connected to the base, and a first spreader that imposes a first force on the fin that causes the fin to spread in response to relative movement between the first spreader and the fin caused by a first longitudinal deflection of the fin relative to the base. A second flipper has a fin and a foot coupling portion connectable to a foot holding portion of a boot to couple a foot in the foot holding portion to the flipper. A first system includes the flipper and the boot. Methods of using the flippers, the boot, and the system are also disclosed.

A dive computer with a free dive mode and/or wireless data transmission capabilities. In one embodiment the invention relates to a diving apparatus including a dive computer having a free dive mode, where the dive computer is configured to calculate a nitrogen loading in the free dive mode using a default value which is the fraction of oxygen in air, and where the free dive mode is used when a diver makes a dive without a self-contained underwater breathing apparatus. Another embodiment includes a method of operating a dive computer including recording two or more first identifiers, receiving pressure information from two or more pressure transmitters, the pressure information comprising second identifiers and pressure measurements, determining whether the pressure information contains one of the two or more first identifiers, and displaying a message indicative of the pressure information that contains one of the two or more first identifiers.

A dive computer with a free dive mode and/or wireless data transmission capabilities. In one embodiment the invention relates to a diving apparatus including a dive computer having a free dive mode, where the dive computer is configured to calculate a nitrogen loading in the free dive mode using a default value which is the fraction of oxygen in air, and where the free dive mode is used when a diver makes a dive without a self-contained underwater breathing apparatus. Another embodiment includes a method of operating a dive computer including recording two or more first identifiers, receiving pressure information from two or more pressure transmitters, the pressure information comprising second identifiers and pressure measurements, determining whether the pressure information contains one of the two or more first identifiers, and displaying a message indicative of the pressure information that contains one of the two or more first identifiers.

Dive computers in accordance with embodiments of the invention are disclosed that store information concerning a dive site. The stored information can be accessed during the dive to provide information concerning such things as points of interest and/or hazards. One embodiment of the invention includes a processor, memory connected to the processor, a pressure transducer connected to the processor and configured to measure depth, and a display connected to the processor. In addition, the memory contains factual information concerning a dive site, and the processor is configured to display at least a portion of the stored factual information concerning the dive site via the display.

Therapy gas delivery systems that provide run-time-to-empty information to a user of the system and methods for administering therapeutic gas to a patient. The therapeutic gas delivery system may include a gas pressure sensor attachable to a therapeutic gas source that communicates therapeutic gas pressure data to a therapeutic gas delivery system controller, a gas temperature sensor positioned to measure gas temperature in the therapeutic gas source that communicates therapeutic gas temperature data to the therapeutic gas delivery system controller, at least one flow controller that communicates therapeutic gas flow rate data to the therapeutic gas delivery system controller, at least one flow sensor that communicates flow rate data to the therapeutic gas delivery system controller, and at least one display that communicates run-time-to-empty to a user of the therapeutic gas delivery system. The therapeutic gas delivery system controller of the system includes a processor that executes an algorithm to calculate the run-time-to-empty from the data received from the gas pressure sensor, temperature sensor, flow controller and flow sensor, and directs the result to the display.

Therapy gas delivery systems that provide run-time-to-empty information to a user of the system and methods for administering therapeutic gas to a patient. The therapeutic gas delivery system may include a gas pressure sensor attachable to a therapeutic gas source that communicates therapeutic gas pressure data to a therapeutic gas delivery system controller, a gas temperature sensor positioned to measure gas temperature in the therapeutic gas source that communicates therapeutic gas temperature data to the therapeutic gas delivery system controller, at least one flow controller that communicates therapeutic gas flow rate data to the therapeutic gas delivery system controller, at least one flow sensor that communicates flow rate data to the therapeutic gas delivery system controller, and at least one display that communicates run-time-to-empty to a user of the therapeutic gas delivery system. The therapeutic gas delivery system controller of the system includes a processor that executes an algorithm to calculate the run-time-to-empty from the data received from the gas pressure sensor, temperature sensor, flow controller and flow sensor, and directs the result to the display.