Wedge calculator

The wedge calculator is used when a vessel is trimmed and the product inside a tank forms a wedge (a triangular shape in side view). This can happen with low volumes where the liquid does not contact all four tank boundaries.

Inputs (what you need)

• Draft aft and draft forward (to get trim).
• LBP (length between perpendiculars).
• Tank length.
• Reference height and distance from aft bulkhead to gauge point.
• Observed sounding.
• Volume from table for the relevant condition (from your tank table).

What the calculator does (high level)

1. Computes vessel trim: aft draft minus forward draft.
2. Turns trim into a trim factor by dividing by LBP.
3. Calculates an adjusted sounding based on trim geometry and gauge position.
4. Checks whether the case is a wedge case (if not, the tool indicates it).
5. Estimates wedge volume using the table volume and the adjusted sounding.

trim = draftAft - draftFwd
trimFactor = trim / LBP

adjustedSounding = obsSounding + (distAftBhd - (refHeight * trimFactor)) * trimFactor
innageForTable = adjustedSounding / 2

If trimFactor == 0:
  wedgeVolume = 0

wedgeLength = adjustedSounding / trimFactor
If wedgeLength > tankLength:
  Not a wedge case

wedgeVolume = (volumeFromTable * adjustedSounding) / (tankLength * trimFactor)

Practical notes

• If LBP = 0 the calculation is invalid.
• If there is no trim (trim factor is zero), the wedge effect is zero.
• Make sure your table value matches the same reference and units you use in input.