Sea Chest, Strainer & Seawater Pump Performance Tool
Sea Chest • Approach Velocity • Suction Loss • Strainer ΔP • Pump Curve • System Curve • NPSH • Cavitation Margin • Parallel Pumps • Power
Sea Chest, Strainer & Seawater Pump Performance Tool
Follow the seawater path from hull opening to pump operating point. Simple mode checks pump/system intersection, flow margin and NPSH. Advanced resolves sea-chest entrance velocity, Darcy suction loss, strainer fouling, multiple parallel pump curves, NPSH available, pump power and warm-water/fouling sensitivity in one live model.
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Fast seawater pump / strainer screenEnter a pump shutoff point and one known curve point. The model intersects that quadratic pump curve with the entered static + variable system curve.Operating pointPump curve × system curve
SuctionStrainer loss & NPSHA
CapacityFlow margin & pump kW
Cooling Requirement & Pump Curve
m³/h required by the cooling system.
m at zero flow.
m³/h at the known curve point.
m.
%.
System / Suction Basis
m, including any fixed discharge-pressure/elevation requirement.
kPa at the pump reference flow, excluding strainer.
kPa at pump reference flow.
kPa at pump reference flow, in addition to strainer.
m; use negative value if pump centerline is above waterline.
°C.
m from pump maker curve.
Sea Chest / Suction Geometry
m³/h.
kg/m³.
mm²/s (cSt), user-entered seawater basis.
kPa absolute.
m; negative if above waterline.
m² after gratings/blanking.
Dimensionless loss coefficient.
m/s planning limit, not a universal class value.
m.
m.
mm.
Valves, bends, reducers, entrance items not separately modeled.
Strainer / Suction Component Register
Rows are treated as active components in the common suction path. Enter current ΔP at the listed reference flow. The model scales pressure drop approximately with flow².
| Use | Component | Reference flow m³/h | Clean ΔP kPa | Current ΔP kPa | User alert ΔP kPa |
|---|
Parallel Seawater Pump Register
Each available centrifugal pump uses H = H₀ − kQ² from shutoff head and one known curve point, adjusted for entered speed by affinity-law scaling. For unlike pumps in parallel, the model sums each pump’s flow at the common head.
| Use | Available? | Pump | Speed % | Shutoff head m | Ref flow m³/h | Head @ ref m | BEP flow m³/h | NPSHr @ expected duty m | Efficiency % |
|---|
Discharge / Operating Limits
m.
m³/h.
kPa, e.g. coolers/piping/valves not separately modeled.
% above required cooling flow.
m above entered pump NPSHr.
% of speed-corrected BEP flow, user-entered.
% of speed-corrected BEP flow, user-entered.
Sea-Water-System Checks
Engineering boundary: the model uses steady incompressible flow, quadratic pump/system approximations and a single suction-header path. It does not model transient air ingestion, vortexing, debris slugs, sea-state pressure fluctuations, pump recirculation, detailed cooler pressure-drop curves or CFD of the sea chest. Maker pump curves and vessel piping data control.