316 lines
8.1 KiB
ReStructuredText
316 lines
8.1 KiB
ReStructuredText
Hydrostatics
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============
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TankOptions
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-----------
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.. py:class:: TankOptions(include_mass=False, include_fsm=True)
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Options for tank handling in hydrostatic calculations.
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:param include_mass: Include tank fluid mass in displacement (default: False)
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:param include_fsm: Apply Free Surface Moment correction to GM (default: True)
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.. py:staticmethod:: none()
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Create options with no tank effects (mass=False, fsm=False).
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.. py:staticmethod:: all()
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Create options with all tank effects (mass=True, fsm=True).
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.. py:staticmethod:: mass_only()
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Create options with only mass included (mass=True, fsm=False).
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.. py:staticmethod:: fsm_only()
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Create options with only FSM correction (mass=False, fsm=True).
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.. py:attribute:: include_mass
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:type: bool
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Whether tank mass is included.
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.. py:attribute:: include_fsm
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:type: bool
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Whether FSM correction is applied.
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HydrostaticsCalculator
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----------------------
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.. py:class:: HydrostaticsCalculator(vessel, water_density=1025.0)
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Calculator for hydrostatic properties.
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:param vessel: The vessel to calculate hydrostatics for
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:param water_density: Water density in kg/m³ (default: 1025.0 for seawater)
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.. py:method:: from_draft(draft, trim=0.0, heel=0.0, vcg=None, num_stations=None, tank_options=None)
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Calculates hydrostatics at a given draft, trim, and heel.
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:param draft: Draft at reference point (m)
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:param trim: Trim angle (degrees)
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:param heel: Heel angle (degrees)
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:param vcg: Vertical center of gravity for GM calculation (optional)
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:type vcg: float or None
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:param num_stations: Number of stations (optional)
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:param tank_options: TankOptions object (optional)
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:returns: HydrostaticState with all properties
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.. py:method:: from_drafts(draft_ap, draft_fp, heel=0.0, vcg=None, tank_options=None)
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Calculates hydrostatics from drafts at Aft and Forward Perpendiculars.
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:param draft_ap: Draft at Aft Perpendicular (m)
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:param draft_fp: Draft at Forward Perpendicular (m)
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:param heel: Heel angle (degrees)
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:param vcg: Vertical center of gravity for GM calculation (optional)
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:type vcg: float or None
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:param tank_options: TankOptions object (optional)
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:returns: HydrostaticState with all properties
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.. py:method:: from_displacement(displacement_mass, vcg=None, cog=None, trim=None, heel=None, tank_options=None)
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Calculates hydrostatics for a given displacement, finding the required draft.
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:param displacement_mass: Target displacement in kg
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:param vcg: Vertical center of gravity (m) for GM calculation (optional)
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:param cog: Full center of gravity (LCG, TCG, VCG) tuple (optional, overrides vcg)
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:param trim: Fixed trim angle in degrees (optional, default 0.0)
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:param heel: Fixed heel angle in degrees (optional, default 0.0)
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:param tank_options: TankOptions object (optional)
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:returns: HydrostaticState with all properties
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.. note::
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When ``tank_options`` is provided with ``include_mass=True``, ``displacement_mass``
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is interpreted as the mass of the vessel **excluding** the fluid in the tanks.
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The total displacement used for calculation will be ``displacement_mass + tank_fluid_mass``.
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.. py:method:: from_loading(loading, num_stations=None)
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Calculates hydrostatics for a given LoadingCondition.
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This method automatically applies the given loading condition (including tank fill overrides), calculates the equilibrium based on total displacement and combined COG, and restores the original tank fill levels.
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:param loading: :class:`~navaltoolbox.LoadingCondition` to analyze.
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:param num_stations: Number of stations (optional).
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:returns: HydrostaticState with all properties.
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HydrostaticState
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----------------
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.. py:class:: HydrostaticState
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Result of hydrostatic calculations.
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**Basic Properties**
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.. py:attribute:: draft
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:type: float
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Draft at Midship Section (MP) in meters.
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.. py:attribute:: draft_ap
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:type: float
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Draft at Aft Perpendicular (AP) in meters.
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.. py:attribute:: draft_fp
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:type: float
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Draft at Forward Perpendicular (FP) in meters.
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.. py:attribute:: draft_mp
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:type: float
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Draft at Midship Perpendicular (MP) in meters (alias for draft).
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.. py:attribute:: volume
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:type: float
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Submerged volume (m³).
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.. py:attribute:: displacement
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:type: float
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Total displacement mass in kg (Volume * Water Density). Represents the total weight of the floating system (Vessel + Tanks).
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.. py:attribute:: vessel_displacement
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:type: float
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Vessel displacement mass in kg (Total - Tank Mass). Represents the input displacement (Lightship + Deadweight excluding tanks).
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.. py:attribute:: tank_displacement
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:type: float
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Tank fluid mass in kg (sum of all tank fluid masses). 0.0 if ``include_mass`` is False.
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**Centers**
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.. py:attribute:: cob
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:type: tuple[float, float, float]
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Center of Buoyancy (LCB, TCB, VCB) vector.
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.. py:attribute:: cog
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:type: tuple[float, float, float] or None
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Center of Gravity (LCG, TCG, VCG) vector, if provided. Matches ``displacement``.
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.. py:attribute:: vessel_cog
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:type: tuple[float, float, float] or None
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Vessel Center of Gravity (LCG, TCG, VCG) vector (Ship-only). Matches ``vessel_displacement``.
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**Waterplane Properties**
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.. py:attribute:: waterplane_area
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:type: float
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Waterplane area (m²).
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.. py:attribute:: lcf
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:type: float
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Longitudinal Center of Flotation (m).
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**Metacentric Radii**
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.. py:attribute:: bmt
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:type: float
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Transverse metacentric radius (m).
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.. py:attribute:: bml
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:type: float
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Longitudinal metacentric radius (m).
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**Metacentric Heights (Corrected for Free Surface)**
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.. py:attribute:: gmt
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:type: float or None
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Transverse metacentric height (Wet/Corrected) (m).
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.. py:attribute:: gml
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:type: float or None
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Longitudinal metacentric height (Wet/Corrected) (m).
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**Metacentric Heights (Uncorrected)**
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.. py:attribute:: gmt_dry
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:type: float or None
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Transverse metacentric height (Dry/Uncorrected) (m).
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.. py:attribute:: gml_dry
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:type: float or None
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Longitudinal metacentric height (Dry/Uncorrected) (m).
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**Dimensions**
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.. py:attribute:: lwl
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:type: float
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Length at Waterline (m).
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.. py:attribute:: bwl
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:type: float
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Beam at Waterline (m).
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.. py:attribute:: los
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:type: float
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Length Overall Submerged (m).
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.. py:attribute:: wetted_surface_area
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:type: float
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Wetted Surface Area (m²).
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.. py:attribute:: thickness_volume
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:type: float
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Volume added by the hull plate thickness (m³).
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.. py:attribute:: contact_surface_area
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:type: float
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Shared area between hulls excluded from wetted surface (m²).
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.. py:attribute:: midship_area
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:type: float
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Midship Section Area (m²).
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**Form Coefficients**
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.. py:attribute:: cb
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:type: float
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Block Coefficient.
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.. math::
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C_b = \frac{\nabla}{L_{wl} \cdot B_{wl} \cdot T}
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.. py:attribute:: cm
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:type: float
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Midship Section Coefficient.
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.. math::
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C_m = \frac{A_m}{B_{wl} \cdot T}
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.. py:attribute:: cp
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:type: float
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Prismatic Coefficient.
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.. math::
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C_p = \frac{\nabla}{A_m \cdot L_{wl}}
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**Free Surface Corrections**
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.. py:attribute:: free_surface_correction_t
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:type: float
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Transverse Free Surface Correction (m).
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.. py:attribute:: free_surface_correction_l
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:type: float
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Longitudinal Free Surface Correction (m).
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**Stiffness Matrix**
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.. py:attribute:: stiffness_matrix
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:type: list[float]
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6x6 Hydrostatic Stiffness Matrix (flattened row-major).
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**Advanced Properties**
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.. py:attribute:: sectional_areas
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:type: list[tuple[float, float]]
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Sectional Area Curve as list of (x, area) pairs.
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.. py:attribute:: freeboard
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:type: float or None
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Minimum freeboard in meters, or None if no deck edges defined.
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