Evaluate the scuba divers weight belt for each individual in any water environment with any set of gears.


Features

• Support any combinations of gears
• Extensive list of pre-defined gears (cylinders, suits, BCDs, regulators)
• Allow to add and edit custom gears
• Detailed computation results (mass, volume, density for each component)
• Metric/Imperial units
• Works offline (except map)
• Detailed steps for a pre-dive weight check

The app is also available as a web app at https://wildbits.github.io/lead/app.html

What

Lead is an app that allows to evaluate the amount of lead required for your scuba weight belt, for every dive and gear configuration.

Lead supports two methods of evaluation, Archimedes and PADI's Basic Weighting Guidelines.

Archimedes method

With this method, Lead evaluates the amount of weight to carry by applying the archimedes principle on the diver body, set of gears in a specific environment. Each element is considered as a mass and volume to compute the resulting buoyancy.

Basic Weighting Guidelines method

With this method, Lead evaluates the amount of weight to carry by following the PADI's basic weighting guidelines. The result is meant to be a starting point for a buoyancy check.

Why

Adjusted scuba weight belt is a key aspect in order to maintain a good buoyancy. Divers are advised to follow basic weight guidelines in order to estimate their scuba weight belt and further tune it through experience in an environment. Ultimately, divers should reach the perfect weighting for a given environment and keep track of it in a log book for further reference.
When diving in new conditions, divers should refer to basic weight guidelines again and start the fine tuning process.

This app aims at providing an initial estimation of the weight belt in any environment.

How

Archimedes method

The app evaluates the minimum amount of weight required so that the scuba diver never ends up being positively buoyant during a dive with an empty BCD and lungs half full. This should allow the scuba diver to control his ascent at any time. The minimum amount of weight is related to the maximum buoyancy which is computed using the Archimedes' principle.

• Water density is computed via a seawater model which takes the water temperature and salinity into account (default values obtained from NASA Open Data service, based on geolocation and date)
• Diver body volume and density is computed via a two-compartment model which takes the diver gender, age, height and weight into account (the volume is computed for a diver holding a normal breath in his lungs)
• Gears volume and mass is computed or derived from data sheets. The maximum volume and minimum mass are considered to compute the minimum amount of lead. Cylinders evaluated as being empty. Suits are approximated depending on the scuba diver body surface and wet suit thickness.

Basic Weighting Guidelines method

The app follows the PADI's Basic Weighting Guidelines and takes into account the buoyancy of the cylinders, the type of suits, the diver fitness (computed through a model).