Producing shells for British 14" Mark VII guns shouldn't be a problem, as it was the bores were the same as the US BB 14/45 cal. and 14/50 cal. Marks - 355.6 mm, the British breeches were taller than the US. The British were familiar with the US guns too, several had been used as railway guns in WWI, they'd been fitted in the Chilean BB Almirante Latorre, and the pair of Abercrombie Class monitors. Richelieu was a different and more complicated matter altogether, her guns actually had a bore of 14.96" or 380 mm, they were re-bored in the US to fire British 15" shells, i.e. 381 mm, which was just as well because French shells had shown themselves prone to blowing up in the breech. Early in the war the British had contracted with US firms to produce artillery shells, they weren't happy with the product. Instead, they increased the volume of their contracts in Canada, and invested in the US. Before Lend Lease, the British Gov't owned the 2 largest explosives manufacturing plants in the US, and had contracted to acquiring artillery shells up to 9.2". Re: Given that the USS North Carolina did not run builder's trials until May 19-20, 1941, and that this deal was likely initiated in February/March, 1941, any problems associated with the USS North Carolina would not have been known at the time. Good point, the problem wasn't noticed until props in the water pre-builders trials. I responded to directly to USMCPrice, my intent was to point out that the dates given weren't valid in regards to ready for combat, problems developed, and they weren't, neither were the SoDaks. DoY was more conventional, and not liable to the same problems. If a deal was made in Feb., on the US side it could be because more fast carriers i.e. "3 Yorktowns" meant that more Fast BBs would be required short term at least. Re: Also, don't forget that the USS Iowa had similar problems to the USS North Carolina and USS South Dakota classes. The USS Iowa would undergo experimental propeller combinations in an effort to dampen the vibrations from April-July, 1943. Sure, but given the problems with the NC's & SoDaks in 1941, if a requirement remained to have US Capital Ships able to overtake their speediest Japanese equivalents as per Intelligence, then the Iowas were certainly needed, the earlier 2 classes would never be able to do it.