Article

Updated App: "Bollard Pull Calculation for Marine Pilots"


by Baykal YAYLALI - published on 17 June 2024 1634 -

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Foreword by Captain M. Baykal Yaylali:

"As you remembered,
I made a bollard pull calculation application for smart phones about 4 years ago with under consultancy of Capt. Henk HENSEN as named BPC.
We made updated and developed new version of app.
Program is served free for global maritime industry as before.
I would like to share it and informed my colleques.
You may follow a few parts of an article as below;

Required tug power and number of tugs needed in variable conditions of wind and current isin most cases an assessment made by pilots based on their professional experience. However, assessments will raise questions by lawyers if something goes wrong. They will use tools to calculate what really is needed with respect to tug power and number of tugs. They have furthermore the advantage of time.

A pilot has not so much time. For a pilot, if tugs are needed, it is hard to calculate the required tug power just before or during ship manoeuvring. Furthermore, the more extreme the weather conditions become the less accurate assessments are and the higher the risk of too little tug power.

A handy and simple tool to determine in a minimum time what is really needed as tug assistance, is the Bollard Pull Calculator which calculates in an approximate way the total required tug power for ships in various conditions of wind and current. This tool can be loaded as an app on the smart phone.

The tool is based on the calculations and graphs as explained in chapter 5 of the book “Tug Use In Port”, written by Captain Henk Hensen FNI; first published in 1997 by The Nautical Institute, London, UK, with a 3rd edition published by The ABR Company, UK, in 2018). Moreover, formulas of linear and non-linearregressions obtained from academic and scientific studies have been digitalized and made suitable for mobile application. (BS 6349-1, OCIMF Mooring Equipment Guidelines (MEG4) 4th Edition 2018, SIGTO’s Prediction of Wind Loads on Large Liquefied Gas Carriers (2007), Post-Panamax Full Loaded Cond. Jare, Andersen I.M.V. (2003), Parameter identification of wind loads on ships, Werner BLENDERMANN [1993])

The program has been tested for more than 5 years and it has been observed that it works in a satisfactorily way."


Teaser pictures:
Teaser pictures
Teaser pictures
Teaser pictures
Teaser pictures
1.0 Introduction

Pilots rely on their extensive professional expertise and the prevailing ship conditions to determine the requisite additional tugboat power and quantity amidst varying weather dynamics. Despite their expertise, pilots face time constraints that hinder accurate real-time decision-making. Compounded by adverse weather, the scope for error amplifies during assessments, risking reduced tugboat efficacy in challenging operational environments. While legally designated as advisors, pilots bear full accountability for precise calculations and subsequent decisions devoid of time constraints or operational pressures. In the event of mishaps, judicial entities and legal representatives promptly scrutinize the situation with proper tools and adequate time allocation to ascertain the authentic tug power and tugboat quantity requisites.

The "Bollard Pull Calculator" stands as a valuable and user-friendly tool for estimating the total tug power essential for navigating ships through diverse wind and current scenarios swiftly, aiming to streamline the determination of optimal tug power and quantity efficiently. Developed based on methodologies outlined in Capt. Henk HENSEN's "TUG USE IN PORT" Chapter 5, seminal works such as BS 6349-1, OCIMF Mooring Equipment Guidelines (MEG4) 4th Edition 2018, SIGTO’s Prediction of Wind Loads on Large Liquefied Gas Carriers (2007), Post-Panamax Full Loaded Cond. Jare, Andersen I.M.V. (2003), Parameter identification of wind loads on ships, Werner BLENDERMANN (1993) and other significant references, this program digitizes and adapts linear and non-linear regression formulas derived from scholarly research for mobile application deployment. Insightful elucidations on calculations are accessible via the program's "ⓘ" symbol, guiding users through intricacies. Further program elucidations are intricately detailed in subsequent sections for comprehensive understanding.

2.0 The Various Sections
A. BPC SECTION
Fig. 1 BPC Section
Fig. 1 BPC Section
Fig. 1 BPC Section
Fig. 1 BPC Section
i. Calculations for required tug power in case of winds
In this section, first the ship type is selected and other data entries are made. Ship types are classified as shown in (Figure 1). Among the values to be entered afterwards, the data entries determined as “Longitudinal Height” and “Frontal Height” are very critical as they are based on user calculation and observation. (Figure 2)

. . .
Download full document as PDF (1,7 MB)
Download full document as PDF (1,7 MB)
Download full document as PDF (1,7 MB)
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BY
Author: Baykal YAYLALI
active marine pilot - Directorate General of Coastal Safety
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