Loading of all deadweight Cargoes

[j.sabourn]

My Query is .... I think the last Deadweight cargo I loaded was in the 70"s and would like to know if the method of working out the tonnage is still the old and trusted way as regards ships figures. One of the important instruments when loading such was the Hydrometer for measuring the S.G. (specific gravity) of the water loading in be it sea or river water. ( Fresh Water 1.000 Sea Water 1.025) on the average 10,000 ton ship the TPI ( tons per inch immersion) being about 8 inches and about 50 tons. In which case if the SG was 1015 then the plimsoll mark could be submerged 10/25 of 8 inches which is 3.5 inches or about 175 tons of cargo. With all the modern aids on ships of today are all these and other calculations now computerized. The closest I ever got to aids as such was a lodicator, which only gave you safe weights to load in a hold and the trim of the vessel, whether so much by the head or stern, but no actual figures given. On the massive deadweight size of present day vessels this arbitrary figure would be multiplied many times of course together with the loss of freight if not taken into consideration. So today is this still the mates job with his Hydrometer his bucket and heaving line for water check and then working out physically, or can one now put a few figures in a machine and have the answers given. Just curious to know how far advanced shipping has become in this aspect to see if it has kept up with every other advancement on ships. Cheers JS

[happy daze john in oz]

I can recall as officers steward seeing none of the junior deck officers working out with some form of model how the cargo needed to be loaded. Somehow I would think such practice is long gone. Computerisation has taken over most tasks so would think this is just another one gone that way.

[j.sabourn]

I have recollections of Tanker mates joining bulkers who seemed at a loss on what was going on. The same as myself on joining a tanker and was thrown in at the deep end but was fortuanate to have an experienced tanker 3rd. mate and a Chief engineer who was very helpful. The pumpman being paid off in Japan, starting and stopping the steam pumps for the likes of the paraffin tanks was the first hurdle. The centrifugal pumps for the 26 other tanks was ok as were started by the E.R. and we only controlled their speed by throttles, for a better word. You usually found those brought up in tankers stayed there and vice versa with dry cargo. I wont mention the cattle boats. This was before having to have a tanker endorsement stamped on your ticket. Shipping today is much more highly specialized today, and a lot of youngsters may go their whole seagoing time never even being on a ship carrying cargo be it oil or otherwise. Cheers JS

[Ivan Cloherty]

#1 So many memories and don't forget to treat that hydrometer with care and respect, just such a simple lump of metal that could mean the difference of being overloaded on arrival or under loaded and the subsequent fine or loss of revenue.................memories, you cannot buy them

[j.sabourn]

Memories are made of this bursting out in song here. The running up and down the quay when finishing off trying to get them to keep the ship upright and finishing up with the right trim. Maybe today just stand there with a laptop don't really know the score today. Know you had to keep the tipping moments per 100 tons in your head for tipping the ship in no.1 hold and the after hold and try and do it in your head. Cross your fingers and also legs at times look to heaven and have faith in yourself. As regards the Hydrometer readings had to take these at various time if the port was tidal as the salinity also changed with the tides. Who was it sang those were the days my friend I thought they"d never end. Was always my favourite as she was quite sexy I thought. Cheers JS

[John F Collier]

Memories are made of this bursting out in song here. The running up and down the quay when finishing off trying to get them to keep the ship upright and finishing up with the right trim. Maybe today just stand there with a laptop don't really know the score today. Know you had to keep the tipping moments per 100 tons in your head for tipping the ship in no.1 hold and the after hold and try and do it in your head. Cross your fingers and also legs at times look to heaven and have faith in yourself. As regards the Hydrometer readings had to take these at various time if the port was tidal as the salinity also changed with the tides. Who was it sang those were the days my friend I thought they"d never end. Was always my favourite as she was quite sexy I thought. Cheers JS

RE: "Those were the day's my friend 1968" Mary Hopkins Welsh Folk singer, lovely voice . Cheers, John F.

[John Arton]

John S
Before loading your deadweight cargo you first had to calculate the quantity to load taking into account;
bunkers and fresh water for voyage
ships constant (crew, water in boilers, lube oil etc.)
Load line zone you are in and zone you will pass through/discharge in.
Once that is done you can then if loading in one zone to discharge in another you can either load more or less according to fuel and fresh water consumed between departure load port and crossing zone change. (could amount to around 1000 tons)
Once you had that you could then calculate (using the loadicator if provided,( new builds plus older ships have now to be provided with an approved loading instrument that not only provides intact stability but also damaged stability, the approval coming from the classification society) to calculate the distribution of your cargo amongst the holds. If loading bulk cargoes the "runs" into each hold are calculated (using the loadicator) to ensure stern trim (necessary for deballasting) is maintained and stress's are keep within limits. Your loading plan would be drawn up to ensure adequate trim was maintained throughout the voyage taking into account any draught restrictions at load and discharge ports.
The final "run" is calculated from draft survey and using MCTC from ships curves (or tables) along with TPC the amount to pour into either the fwd or aft holds is calculated to give the final sailing trim required.
That final calculation is relatively simple and there always was a page in the stability book showing how to carry out the calculation.
With modern computers this can be done at the click of a mouse button but what most officers at sea fail to recognise is that the loading computer is just a mechanised version of the ships stability booklet, which is still a requirement to be carried under SOLAS. On one small chemical tanker I was Captain on that underwent a 6 month dry docking and upgrading I actually sat down every night and each weekend, transposing all the cbm's against ullage depths for each cargo tank and all the hydrostatic data from the tank tables and stability book, into a program that gave the weight of cargo in each tank plus the GM and draft when loading. All of this took mindless hours sitting in my hotel room with the superintendents lap top inputting the data into a Microsoft office application (excel) and then building macros that did the necessary calculations.
Going back to the original workings requiring voyage details with steaming distances and consumptions between ports and zones, no doubt there must be modern loading instruments that have those features built into them but I never saw one whilst I was at sea.
With regard to the hydrometer for obtaining the density of dock water and hence the dock water allowance that could be applied to your final draught calculations, then do any modern seafarer even understand of the importance of the metal hydrometer stowed away in the mates office or the fact that it is a statutory requirement to have such? If you could not find it you could always borrow the engineers glass one used for testing boiler water salinity but that was a cheat as was looking up in Browns nautical Almanac where dock water densities of ports around the world was listed along with, if I recall correctly, the pro forma for calculating how much cargo to load in order to change the trim one centimetre and where to load it. (it was all basic stability taught in 2nd mates, bilging only came into the mates stability if I recall correctly)
rgds
JA

[j.sabourn]

All a long time ago now John. Certain subjects could pick up again. As regards zonal areas was always a lengthy calculation. Leave it all now to modern methods. Just like to watch the ships go by and say there but for the grace of God go I. Cheers JS

[Ivan Cloherty]

John S

if I recall correctly, the pro forma for calculating how much cargo to load in order to change the trim one centimetre and where to load it.
JA

What's a centimetre? only knew feet and inches!

[j.sabourn]

#9... Just another small part of our lost heritage Ivan, the same as fathoms and feet, miles and furlongs, cables and nautical miles, pounds shillings and pence, and fousands of uvvers. last time in UK see you still have the speedometers in cars with Kilometres and miles. We only have kilometres on ours. Yus "ii have to get modern like us. As regards shipping the old draft figures being 6 inches high and 6 inch space between, and are now called decametres , wont even try with the plimsolls as may put you off trying to read the draft. Think it best we kept to our memories. If you get in quick Cappy is paying for free nights out. Cheers John S