Dear Juliancw,

Whether your criteria are sufficient or not. cannot be judged on just a few data and on the little information you are supplying here.

I found in a book an approach velocity of 0.30 m/sec for ships over 10000 tons under difficult conditions.

In berthing (big) ships a lot of factors play a role:

Ship size

Empty, ballasted, fully laden.

Propulsion efficiency

Wind speeds

Wind direction

Tug boats

Skill of tugboat crews

Wave regime at berthing site.

Possible currents

Acceptable hull stress at contact place with fender.

Etcetera

A port, where 300000 dwt ships are berthed should be designed in a hydro laboratory and tested in a simulator.

Also investigate and visit other ports with similar conditions and evaluate the experience made in those ports.

Do not make expensive mistakes on your own.

Take care ■

Dear Julian CW,

your parameters seems to be higher than acceptable;

I am be involve in projects which accept this parameters:

berthing velocity: claimed 0,15m/sec given 0,10m/sec max

vessel dwt 400.000

condition: exposed in certain seasons;

4 tug 50/70 bp

hope be usefull but may be litlle late

wellstay ■

Originally Posted by Juliancw

Hi all,

I am looking at different design guidelines for a berth in open water and would value member’s opinion on the design criteria of a ship berthing a new terminal.

The ships berthing here would be around 330000DWT and we would have 4x70t tugs in operation. We would berth in winds speeds of around 30 knots or less.

We have been given these base line criteria but feel this may not be enough in an open port.

"The marine structures shall be designed for the berthing impact from the design vessel in full ballast. Design berthing velocity to be 0.2 m/see, 1/4 point landing. The fender system shall be able to absorb the energy of the design berthing impact at 25 % deflection."

Just interested if anyone thinks this is excessive?

==========================================================

There suggestion in my opinion is not excessive.

Your vessels size and surface area above the water line will go hand in hand with its wind bearing loads and sea condition. It is essentially no different than a naval gunnery target that has broken from its anchor.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Stupid question- why are you not thinking of winching it into place (assuming you have a three sided berth) or using by the tugs to counter the force of a number of winches pulling it to the berth/jetty? The same could be used for controlled casting off etc.

Teus is right about designing your berth in a laboratory and visiting other berths. ■

In open water you would have no keel drag nor surge pressure. What do you mean by open port? If you are berthing in the roads then you should have some keel drag & surge pressure. Besides commissioning a study at Delft you might care to reference the Yokohama Fenders Manual which will give you the bething energies & calculation formulae for most vessels.

As mentioned already, hull pressure is the baby in the bathwater. Your concerns are justified because if you design for 0.2m/s quarter point berthing like the specification mentions, does that mean that all situations are covered?

I developed a spreadsheet covering the berthing energies of all the vessel types in the Yokohama Handbook in 1989 but lost it on my travels. It's not hard to make another: Yokohama's Dusseldorf office were most helpful & in recent dealings with the HQ in Japan they have also been helpful, but things have been harder to explain. Perhaps you will have better luck.

Take care (I hope I'm not infringing TT's copyright ) ■

Dear louispanjang,

I am not aware of having any copyrights, but you make me curious which copyright I might be overlooking.

As long as I am being copied right, it is OK.

Take care

Teus ■

Teus,

Your closing remarks are often 'Success' or 'Take Care'. My closing remark 'Take care' was an essential copy to your own. It is vital that Juliancw does take a lot of care in this project, so I had to borrow from you.

Cheers. ■

Dear Juliancw

The best way is calculate basing on BS standard 6349:1-2000, where you can find official theory

If need help, can contact me by skype: nguyenhcmc

Brgds

Nguyen pico ■