Screwing cotton during lading:

“A method of stowing cotton, at one time more generally in use than at present, is to screw the bales into the hold of a ship. The screwing is done in this way: The bales are stood on end close together in a semicircle, the concave side of which faces an inside wall of the hold. Pressure is then brought to bear upon the convex side of the semicircle until it is forced flat up against the wall. Then a second semicircle is formed of other bales placed close together and these in turn are brought up against the flat surface made by the preceding row of bales; then a third row is put into place, and so on until one layer of cotton is formed in the hold. The next layer may be composed of bales placed on their sides and not packed so tightly as the first one. A third layer is made of upright bales screwed into position in the manner described, and the operation is continued until the cargo is complete. By this means cotton is packed into a space much smaller than would be required for the same number of bales set closely, but without the use of such pressure. The screwing is done by means of power screws operated by hand. The men who do this work and also their overseers require special training. An inexperienced laborer would suffer greatly from exhaustion if he tried to stand with two or three experienced screwmen turning the levers of a cotton screw. This service is expensive and is resorted to only when it is especially desirable to economize cargo space, but it is still common enough to keep the screws from rusting at the Southern ports. At some ports, as Mobile, the practice is still general, but at Savannah as a rule the screws are called into use only when some odd corner of a cargo needs filling out.

One of the chief causes for the decline in this method of stowing cotton is the increase in the size of freight vessels. A large ship will call for a load of cotton, take 20,000 or more bales, which are stowed closely, but without the use of screws, and the vessel puts to sea again in a short time. A smaller ship may spend a week or so having 15,000 bales screwed into its hold, in order to gain the extra freight paid on the additional bales which this method of packing makes possible to cany.

Another advantage of screwing cotton bales into position is a reduction in the danger from fire that might be caused by the iron ties around the bales chafing against steel or iron parts of the hold. This advantage may be offset in some degree by the possible injury to the hull of the vessel due to the outward pressure of the closely packed bales. Another disadvantage in screwing cotton is the difficulty of unloading. Sometimes the spars to which the unloading tackle is attached are broken before a bale can be pulled from one of the closely packed layers, and sometimes it is necessary to tear one bale to pieces before others in a layer can be moved.

[Andrews, F, Ocean Freight Rates, USDA Bulletin 67, (Washington: GPO, 1907, pp.39-40)]

And it's like a lint blizzard down there the whole time.