User manual

Table Of Contents
Understanding the Ballast Sheet
A detailed description of ballast calculations and a sample ballast sheet are included in
the section that follows.
Deployment Parameters
The deployment parameters on the ballast sheet are the in situ pressure, temperature,
salinity, and density of water at the planned neutral depth for the deployment. That density may
be available directly or it may be calculated, using an equation of state for seawater, from
measurements of pressure, temperature, and salinity at the neutral depth. The neutral depth is
generally the mid-point of the planned profile. The MMP is less compressible than seawater, so
its buoyancy increases as it profiles down and decreases as it profiles up. To avoid exceeding the
lift capacity of the profiler at the deep and shallow limits of travel, the aim of the ballast
calculation is to make the MMP neutrally buoyant at the mid-point of the profile. Maintaining
neutral buoyancy at the mid-point also reduces drive train losses, which increases endurance.
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