Description
Select the right tug for your barge and also find out the limiting towing speed during the voyage using this simple calculator.
What does this Excel Sheet do?
This Excel sheet helps you calculate the following:
1. Required Static Bollard pull of a Tug used for towing a Barge
2. For a given environment, it calculates the limiting towing speed possible for the tow
How to use this excel sheet?
The Excel Sheet has three different sections: Inputs, Static Bollard Pull and Limiting Speed
Principal particulars of the Barge and the dimensions of Cargo are to be provided in the ‘Inputs – Vessel & cargo’ worksheet
The environment inputs are of two types: one for calculation of static bollard pull (STALL condition), and the other one for calculation of limiting speed (TOW condition)
Once inputs have been provided, the app calculates the Static Bollard Pull and the Limiting Speed
For some inputs, Tables and charts are required to be referred. These Tables and charts are provided alongwith for the user to enter these inputs.
The input cells are all in blue. Some critical outputs are in light orange. All parameters are in SI units
Limitations
It can be used only for Cargo height upto 91.5 m from sea level
Cargo is taken to be rectangular in section
Shielding effects are ignored when calculating the windage area of cargo/superstructures
References
1. DNV-RP-H103, 2011, Sec 7.2.6
2. DNV-ST-N001 Table 11.13
3. ABS Rules for Building and Classing Mobile Offshore Drilling Units, 2019, C 3-1-2/1.3.2
Henrik Krolmark (verified owner) –
Was very happy with this as it quickly gave me an overview of a proposed tow.
RAUL (verified owner) –
excelent product
Sankar Arughadhoss (verified owner) –
Hello. good product. In the excel “limiting Speed” tab, in the table you have speed along with wind, current, wave and TPR, I could not understand the higher the sailing speed the wind, current and wave loads increases. could you explain this to me. How this is calculated. Attached image of table from excel sheet.
Team TheNavalArch (store manager) –
Dear Sankar
Thanks for the review and feedback.
The rise in the forces due to rising sailing speed is due to the fact that the ‘relative’ speed of the wind/current rise when the vessel starts moving. For example, if the wind speed is 10 knots and the vessel is moving at 5 knots speed, the effective wind speed is 15 knots. Hope that clarifies.
Team TheNavalArch
carlos ivan (verified owner) –
good