What is formula for calculating the bollard pull of a ship?

What is formula for calculating the bollard pull of a ship?

Step 1 – Determine the environmental parameters (Open Ocean or Benign) Step 2 – Calculate the Wind, Wave and Current forces on the vessel. Step 3 – Add up the wind, wave and current forces to find the total force on the vessel, F. Step 4 – Get the towing efficiency of the tug, ƞ

How is bollard SWL calculated?

Bollard Pull Calculations

1. Actual pulling force (in kN) = (Bollard Pull Force in kN) x (Efficiency Factor)
2. Resistive force (R) = (0.5) x (Density of water) x (Wetted surface area of the hull) x (Velocity of the vessel)2.
3. Available Bollard Pull = (Bollard Pull measured) – (Force utilized by the tug)
4. Summary.

How much force can a tugboat pull?

As a guideline, for example, a 10,000 IHP boat can provide around 100–140 tons of static bollard pull. In reality there are other factors at play, such as the propeller(s) type, whether it is single or double screw, and the towboat draft.

How many tugs do you require?

Ships normally using one or two tugs will, when using more powerful tugs, still use one or two tugs. Even ships using, for instance, four tugs on arrival generally use the same number of tugs when even more powerful tugs become available.

What is static bollard pull?

The bollard pull of a vessel may be reported as two numbers, the static or maximum bollard pull – the highest force measured – and the steady or continuous bollard pull, the average of measurements over an interval of, for example, 10 minutes.

How much thrust does a tugboat have?

They can provide 360 degree thrust, have low risk of capsizing, and can work sideways. Downsides are less pull compared to newer ASD tugs, high maintenance cost, and complexity.

What is breast Line ship?

Breast Line(s) is a mooring-rope or hawser leading approximately at right angles (90°) to the wharf from the vessel lying alongside. May be used from the bow, midships, or stern. Their function is to keep the ship snug against the dock.

What is a Bitt on a ship?

Bitts are paired vertical wooden or metal posts mounted either aboard a ship or on a wharf, pier or quay. The posts are used to secure mooring lines, ropes, hawsers, or cables.

What is bollard in ship?

A bollard is a short post, especially one used for mooring a boat. If you visit a working harbor, you’ll see many bollards. Bollards are known for being especially sturdy, strong enough that a boat securely moored there can’t be blown or tossed around.

What is static tow?

Static towing is an operation that aims to safeguard offshore F(P)SO and SPM terminals against physical contact from visiting tankers. The scope of these operations is detailed in the relevant sections of GOTO.

What is after perpendicular in ship?

The after perpendicular, or aft perpendicular, noted AP, is a line drawn perpendicularly to the load line through the after side of the rudder post or through the axis of the rudder stock.

How do you calculate the force of a ship?

There are multiple ways of doing the force calculation, depending on the time and resources at hand. Model Testing – Tank tests in a basin can be performed on ship model to evaluate the behavior of the vessel in sea, and to provide the design motions and accelerations.

What is required towing force?

The required Towing force is defined as the force which is required to HOLD the vessel in sea under certain environmental conditions of wind, wave and current. Total Towing Force, FTOT = Wind Force + Wave force + Current force

Is the towing force the same as the holding force?

Please note that the towing force is the required force for HOLDING the vessel (also called STALL condition), and not for towing it. Now, what are these environmental conditions and where do we get them from?

What are towing operations?

Towing operations involve the pulling of a vessel (it can be a barge, ship or an offshore structure) using another vessel (usually a tug). From a very basic point of view, we can draw the following conclusions regarding towing The harsher the environment, the more will be the towing force required