# Hello



## Markt (Oct 6, 2010)

Hi i am new to this forum and new to shipping.

i would just like to know how volume of tonnage is measured in 'Air' and in 'VAC' ?


----------



## fred henderson (Jun 13, 2005)

*Welcome*

A warm welcome to SN from the Moderating team. I hope that you will enjoy your membership and join in our activities.


----------



## david freeman (Jan 26, 2006)

*Tonnage measurement*



Markt said:


> Hi i am new to this forum and new to shipping.
> 
> i would just like to know how volume of tonnage is measured in 'Air' and in 'VAC' ?


You have lost me? Tonnage is a regulation figure for charging dues? What do you mean 'Air'' Vac'. Tonnage is a cubic measurement by imperial units or metric units.


----------



## Markt (Oct 6, 2010)

david freeman said:


> You have lost me? Tonnage is a regulation figure for charging dues? What do you mean 'Air'' Vac'. Tonnage is a cubic measurement by imperial units or metric units.


oh. thanks david. 

basically, on a 'Bill of Lading' there are two different metric tonne figures for how much the ship has loaded .

example -

1) 5000 MT AIR
2) 5250 MT VAC

I was just wondering how these figures are calculated and what the difference air and vac is


----------



## david freeman (Jan 26, 2006)

*Tonnage*



Markt said:


> oh. thanks david.
> 
> basically, on a 'Bill of Lading' there are two different metric tonne figures for how much the ship has loaded .
> 
> ...


I am afraid I am not much help of 'AIR' or 'VAC' You need to be a reader of regs and the appropriate latest tonnage regs may help? There Is Tonnage registered by the Flag state and adopted by class, and then there used to be Suez Tonnage/Panama Tonnage.
'VAC' I wonder if this is voyage on commencement and 'AIR' Tonnage minus consumables such as stores and fuel at the port of dischage-THE ANCHRONM has me. (Arrival in Port of discharge- ie. demurage)
Some kindly old master/captain/skipper/ ships agent may be able to be more presice?


----------



## gdynia (Nov 3, 2005)

Welcome onboard to SN and enjoy the voyage


----------



## smithax (Jul 16, 2009)

Markt,

Hazy memories but...
The weight of an oil cargo can be quoted as a weight in air or in a vacuum.
When converting from cubic metres to tonnes a small correction is applied to the correction factor, either .0001 or .0002 I think, to change from the weight in air to weight in a vacuum.
Details will be in the ASTM 6B tables.

I will google it to see if can check on my explanation, and/or get more info.

S


----------



## smithax (Jul 16, 2009)

Google is your friend

The weight of an object is different in air to that in a vacuum as the object is being supported to a small degree in air. 

This is the same as an object being placed in water, the weight will decrease as it is being supported by the water.

S


----------

