Most of Coal Fired Steam Power Plant (CFSPP) are located along the coastal line and need its own port facilities to unloading the coal. To unload the coal, various type of coal unloading jetty have been built. No matter the type of the jetty we choose, there are something which can’t separated from the jetty structure, they are fender and bollard.
Choosing the right fenderand bollard are important to optimize the structure, safety berthing operation and to minimize the cost.
In this session, we will talk a little bit further about fender. Bollard will be discussed later on.
Ok, first of all…what is fender and why we need it installed in the jetty?
- A fender is a bumper used to absorb the kinetic energy of a vessel berthing against a jetty, quay wall or other vessel.
- Fenders are used to prevent damage to boats, vessels and berthing structures. To do this, fenders usually have high energy absorption and low reaction force.Fenders are typically manufactured out of rubber, foam or plastic. However, long time ago, fender are traditionally made of rope
Ok, now we all know what is fender and its function. Next, is the type of fender.
- There are many types of fender at this moment which can be used according to our need. Commonly, fenders are devided into a few types: high performance fender, modular fender, multi purposes fender, pneumatic fender, and foam fender. For more detail, you may visit http://www.trelleborg.com/en/Marine-Systems/
Wowww, so many options we have for fender. How to choose the right one?
- Choosing the right fender is not an easy thing to do, but thanks goodness we have many standards around the world which can be used as our guidelines to choose and design the right fender. Some of the standards are: BS6349 (part 4:1994), BS6349 (part 1:1995), EAU-1996 (for Germany market), Rom 0.2-90 (for Spain markets), PIANC Fender Guidelines 2002.
- The type of fender that is most suitable for an application depends on many variables, including dimensions and displacement of the vessel, maximum allowable stand-off, berthing structure, tidal variations and other berth-specific conditions. The size of the fender unit is based on the berthing energy of the vessel which is related to the square of the berthing velocity.
Let’s go deeper for the required data in fender design
For the ship data, the following items are needed:
- smallest, largest and intermediate ship
- Length(s), beam, draft and freeboard
- bow flares
- special hull features
- hull pressures
Becareful when we have to decide the berthing velocity since the fender size and reaction are mostly affected a lot from this value. Recommendation for berthing velocities for various vessel size can be found in BS 6349, PIANC and/or other relevant standards.
For the tides, we have to keep in mind for the following things:
- the largest tides
- small tides variations are as important as large tides
- vessels should not “sit” on fenders as high tides drop
- vessels should not get caught underneath at low tides
- sometimes ships/vessels/barges can only berth at high tide
- consider access for maintenance
(To be continued)