Ship Design MBL Calculator – IACS

Description

What does this Excel-based app do?
This Excel app helps you calculate a ship’s design MBL as per IACS Rec.10
Ship’s design MBL is an important parameter that can be used further to select the towing and mooring fittings
Calculates the windage area (side) for the calculation of the Ship Design MBL
The side projected area is calculated according to IACS UR A1 Rev 7
It also calculates the minimum number of mooring lines and length of mooring line
Calculates rigorously all the corrections to Ship Design MBL due to environment, exceeding the threshold of 130 t, or deploying a higher/lower number of lines

How to use this App
Select the appropriate calculator by clicking the button on the right: EN > 2000 or EN <= 2000
The user is asked for vessel’s details, projected areas of hull/superstructure etc.
All input cells are in blue. Do not disturb the other cells
The side projected area calculation can be done thoroughly using the spreadsheet
If side projected area is available from an alternate calculation method, it can be directly input into the spreadsheet

Limitations
Ship is moored to solid pier that provides shielding against cross current
Environmental Limits for ships with EN > 2000
Maximum current speed of 1.0 m/s
Maximum wind speed vw, in m/s:
vw = 25.0 – 0.002 (A1 – 2000) for passenger ships, ferries, and car carriers
with 2000 m2 < A1 ≤ 4000 m2
= 21.0 for passenger ships, ferries, and car carriers
with A1 > 4000 m2
= 25.0 for other ships
The wind speed is considered representative of a 30 second mean speed from any direction
and at a height of 10 m above the ground. The current speed is considered representative of
the maximum current speed acting on bow or stern (±10°) and at a depth of one-half of the
mean draft.
Additional loads caused by, e.g., higher wind or current speeds, cross currents, additional
wave loads, or reduced shielding from non-solid piers are not considered

References
1. IACS Rec 10
3. IACS UR A1 Rev 7 (2020)
3. IACS UR A2 Rev 5 (2020)