General HydroStatics
Ship Stability Software |
Command of the Week
(New or interesting aspects of GHS that you may not know about) |
ADD DELTA
|
How would you go about finding where to locate deck cargo
so as not to affect trim? Every naval architect knows that's
what the center of flotation is good for.
Take the problem of finding the weight of the cargo that would immerse the ship to a given draft while keeping the same trim: You would set the target draft, observe the new hydrostatics, and issue an ADD command for whatever the difference is between the new displacement and the existing vessel weight, locating it at the CF. No need to copy numbers; do it in one run. For example, given this initial condition with the desired draft set to 4.120: |
The setup for the ADD command would be,
VARIABLE W SET W={DISPL} MINUS {WEIGHT} ADD "CENTER CARGO HERE" {W}, {LCF}, {TCF}, 6.0 SOLVE |
The result is not perfect because the trim changed slightly
and the draft is not quite on target. This is primarily due to the fact that
the CF changed.
A quicker and easier way to hit the target is to use ADD DELTA. For example, ADD "CENTER CARGO HERE" DELTA, ?, ?, 6.0 |
Questions, comments, or requests?
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