What does this Excel-based app do?
This Excel app helps you design/select a towing chock as per IACS UR A2
Towing chocks can be used for multiple purposes
“Normal” towing means towing operations necessary for manoeuvring in ports and sheltered waters associated with the normal operations of the ship
“Other” towing to assist the ship in case of emergency as given in SOLAS Regulation II-1/3-4 Paragraph 2
This Excel app performs rigorous checks for the chock:
Checks the towing chock for bending, shear, and axial stresses
Checks the chock seating for bending, shear, and axial stresses
Checks the chock and chock seating welds fo adequacy
*Note: If the chock fails, a FE Analysis is recommended
How to use this Excel Sheet
The user is asked for the required geometry, material properties and loads on the chock. The Input cells are highlighted in blue.
The user has to provide all the inputs highlighted in blue.
The Ship Design MBL as per IACS can be determined using another product on TheNavalArch. See
Once all inputs are provided, the spreadsheet will evaluate the chock and chock seating strength
Not to be use to design chocks involved in escort towing, canal transit towing and emergency towing of tankers
1. AISC ASD 9th Ed
2. IACS UR A2 Rev 5
3. IACS Rec 10
4. SOLAS Regulation II-1/3-4 Paragraph 2
Version Date Notes
0.0 7-Jun-22 First Issue