Efficient Trimming Techniques or Methods for Cement Ships

Posted in: , on 8. Sep. 2014 - 10:34

Dear All,

I'm currently working on a project to improve trimming techniques or methods for ships carrying cement.

When reaching the trimming stage of the hold trimming workers are sweeping the tank tops of the ship, i was wondering if this process could be automated.

Please share your views,Thanks in advance.

Re: Efficient Trimming Techniques Or Methods For Cement Ships

Posted on 8. Sep. 2014 - 08:43

Dear shankar,

Trimming a ship is done when the loading of a ship is almost complete and the procedure of trimming is adding cargo on port or starboard, forward or aft, in order to get the ship at an even keel and without list before sailing.

I assume that you are referring to the stage where bulk ships, carrying a cargo of cement in the holds, are cleaned up.

Unloading ordinary bulks ships transporting cement is normally done by a pneumatic cement unloader or a screw unloader.

A screw unloader is known for its poor clean up capabilities, due to the technology of the screw.

A pneumatic unloader performs much better in the clean-up stage, because the suctioning can clean the tank top almost 100%.

A front end loader moves the cement to the suction nozzle.

Automating this works has been tried for many years, but never succeeded.

Although, there is one solution, where the unloading and the clean-up of cement is fully automated:

The self-unloading cement carrier.

Have a look at:


Have a nice day


I'm A Bit Abaftled

Posted on 9. Sep. 2014 - 04:30

It is not clear why you are sweeping the tank tops. Please explain the issue in more detail.

It reads that during trimming you are spilling surplus cement onto the hatches and clearing this debris away manually. This situation is hard to understand.

If, as Teus says, you are manually cleaning the holds then your vessel size determines what clean up methods are available. If the vessel is small sweeping seems plausible although not desirable or agreeably healthy. Larger vessels usually employ a Bobcat, or similar, to move remnant cargo to within reach of the unloading device. Again the work is dirty and dusty with excessive machine wear and air cleaner replacements. I am not aware of any electrically driven AGV being used to clean out ships' holds. I am not even aware if this would be permitted although collision damage should be eliminated.

Until designers of bulk carriers pay proper attention to unloading methods then the problem will persist. Unloading time is minimised by all other forms of transport. Bulk carriers, at best, rely on the ship's gearing to grab material and hurl it over the side. More often they provide next to nothing to help the unloading work.

Carlsen type ships are helpful, even essential, where there are no unloading facilities on the wharf. If there are wharf machines then an easier way to automate clean up would be to stack the hatches abaft so that alternate hatches would be opened up to the ship's rail, almost. This would allow direct access to the hold sides and automate the clean up process. It's a MacGregor thing. For loading the holds would be stacked normally.

John Gateley johngateley@hotmail.com www.the-credible-bulk.com