car carriers and angle of loll

General maritime and engineering discussion occurs on this board. Feel free to post newsbits, comments, ask questions about maritime matters and post your opinions.
User avatar
JK
Enduring Contributor
Posts: 2676
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

car carriers and angle of loll

Postby JK » Mon Feb 01, 2016 10:59 am

OK, you experts, what the heck is up with all the car carriers hanging over and staying there?
Are their stability that fragile? How are they being approved if they do this at apparently random times?

User avatar
Merlyn
Fleet Engineer
Posts: 745
Joined: Wed Dec 25, 2013 7:19 am
Currently located: South Coast UK

Re: car carriers and angle of loll

Postby Merlyn » Tue Feb 02, 2016 7:06 am

It's because the owners want to avoid dry dock charges and on a fine day they can A/F one side of the ship FOC?
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

User avatar
JK
Enduring Contributor
Posts: 2676
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: car carriers and angle of loll

Postby JK » Tue Feb 02, 2016 9:41 am

LOL

User avatar
JK
Enduring Contributor
Posts: 2676
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: car carriers and angle of loll

Postby JK » Wed Feb 03, 2016 3:54 am

They're bringing the latest listing car carrier into Bilboa. It has a cargo of logs from Gabo to LeHavre. Logs are banned to be exported from Gabon.

User avatar
Merlyn
Fleet Engineer
Posts: 745
Joined: Wed Dec 25, 2013 7:19 am
Currently located: South Coast UK

Re: car carriers and angle of loll

Postby Merlyn » Wed Feb 03, 2016 7:46 am

Gabo v Gabon?
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

User avatar
JK
Enduring Contributor
Posts: 2676
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: car carriers and angle of loll

Postby JK » Fri Feb 05, 2016 6:55 am

Gabon
iPad keyboard

User avatar
Big Pete
Engineering Mentor
Posts: 785
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: car carriers and angle of loll

Postby Big Pete » Sat Feb 06, 2016 12:43 am

Having sailed on Car Carriers, the last thing you want is a too stable" i.e. "stiff" ship, because it would roll like a pendulum and the cargo would break free. The ideal is a fairly small GM which gives a "lazy Roll" with no big accelerations to stretch the cargo lashings and work them free.
However, in this condition it is essential to watch the "Free Surface Affect" like a Hawk, and the Engineers and Mates have to work together to maintain the list and trim using both Fuel and Ballast Tanks in such a way as to minimise Free Surface Effect.
A further complication is "Wind Induced List", because Car Carriers are very High Sided, any wind on the side causes them to heel, pumping Ballast to correct this, can leave the vessel vulnerable to flopping over in the opposite direction when the relative wind changes. On an old car carrier with an inexperience Mate I used to get called out every half hour all night with a furious tirade that I must have transferred fuel because the List had changed and I must go down the ER to pump Ballast and correct it. The Mate just couldn't understand that every time the relative wind speed / direction changed, the List changed.
I suspect most of the problems are incurring on modern ships with "Auto Heel" tanks, where the Mates and Engineers leave everything to the Automation, and ignore the Free Surface Effect.
The Car Carrier that capsized coming out of Southampton after Bunkering, last year, obviously had a FSE problem, I am not sure if the requirement to reserve Tanks for LSFO had any bearing on this. Practically you are always going to have at least one slack LSFO and one slack HSFO tank.
I was always taught to run fuel tanks empty, and fill them in pairs P&S, when Bunkering, but many Engineers now just open the filling valve to every tank full and let the fuel flow in, leaving every tank slack unless they are taking capacity Bunkers.
Many of the Eastern European Engineers have no knowledge of stability at all.
I had a Polish Second Engineer join my ship with a brand new Chief Engineer's Certificate and a "Degree" from a "Technical University" in Poland. I asked him what he had to do in order to get his qualifications, he told me it was very difficult, he had to dismantle an air compressor and rebuild it!!
No sort of Engineering Exam / training to my mind, just a trade test for a service Mechanic/ Motorman.

BP
It is always better to ask a stupid question than to do a stupid thing.

User avatar
JK
Enduring Contributor
Posts: 2676
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: car carriers and angle of loll

Postby JK » Sat Feb 06, 2016 5:14 am

Now that makes better sense. Thank you.

User avatar
Big Pete
Engineering Mentor
Posts: 785
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: car carriers and angle of loll

Postby Big Pete » Mon Feb 08, 2016 1:08 am

A further point I should have mentioned is that cars and trucks have their own "Free Surface Effect", the rolling chassis is securely wedged and lashed down, but all the upper works are free to move on the suspension, which can obviously contribute to stability problems.
Similar to the old "Meat Boats" when frozen carcasses were suspended on Meat Hooks from Deck head rails, the effective Centre of Gravity of the Meat was the Deck head rail, rather than the centre of the Meat.
And of course the famous Naval Arch Stability question of the weight on the Deck of the ship that is lifted by the ship's crane/Derrick. As soon as the Crane takes the weight the C of G of the weight effectively becomes the point where the crane wire makes contact with its sheave.
BP
It is always better to ask a stupid question than to do a stupid thing.

User avatar
JK
Enduring Contributor
Posts: 2676
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: car carriers and angle of loll

Postby JK » Mon Feb 08, 2016 5:10 am

I expected a automatic ballasting system issue, but the slack fuel tanks is surprising.
you would not expect that cars rolling on their suspension would be an issue, but when it is thousands it would add up.

User avatar
JK
Enduring Contributor
Posts: 2676
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: car carriers and angle of loll

Postby JK » Wed Feb 10, 2016 4:44 am

I was just reading that investigators looked at the cargo stowage and it was perfectly done. They are struggling to explain the list.

User avatar
Big Pete
Engineering Mentor
Posts: 785
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: car carriers and angle of loll

Postby Big Pete » Wed Feb 10, 2016 11:40 am

With Logs on open Decks it can be caused by the logs on the Weather side absorbing Sea Spray and becoming heavier, a well known problem on timber carriers, but I would think that on the car carrier the logs would have been stowed internally, on the car Decks.

BP
It is always better to ask a stupid question than to do a stupid thing.

User avatar
Merlyn
Fleet Engineer
Posts: 745
Joined: Wed Dec 25, 2013 7:19 am
Currently located: South Coast UK

Re: car carriers and angle of loll

Postby Merlyn » Thu Feb 11, 2016 12:29 am

A lot of vehicles are fitted with air bags ie air suspension nowadays, maybe they were pumped up too high thereby raising the C of G? Just a thought.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.


Return to “Crew Mess”

Who is online

Users browsing this forum: No registered users and 1 guest