Patrick Cadell's book, The Iron Mills at Cramond, contains an appendix listing seven types of iron hoop supplied by the company. They vary in length from 5 ft 11 in (shortest coopers plate hoops) to 24 feet (longest vatt hoops) and in width from one inch (Spanish and Madeira hoops) to three inches (widest vatt hoops).

Instructions are not given on how to fit one. Presumably it is curved round the neck of the cask, cut to the correct length, and sealed with a blacksmith's weld.

The Navy's casks have to last a long time at sea. If one is not properly sealed, the contents will rot. Bad news for the crew, and for the ship's purser who has to keep them fed.

Cort's experiences with hoops are well covered in the Watson-Dundas memorandum of May 1790 (National Archives of Scotland document GD51/2/10/2).

In the year 1780 Commissioner Kirk of the Victg Office applyed to Mr Cort to make some Iron work which the Commissrs of that Board had occasion for at the port of Portsmouth, and in the course of conversation asked him if he could make Iron Hoops.

From Watson-Dundas memorandum, 1790

Some commentators have assumed that Cort is asked to make mast hoops for attaching ships' rigging. But such a request would have come from the dockyard, not from the Victualling Office.

According to Commissioner Kirk, the Navy's hoop suppliers "combined together at the time of tendering for the Contract and had the price they demanded". He wants Cort to undercut these suppliers. The suppliers are not happy when they get wind of the negotations

At the time this Contract was in agitation with Commissr Kirk the combined contractors got some intelligence of the intention and two of them came down to Fontley with an air of menace.

From Watson-Dundas memorandum, 1790

Cort ignores their threats.

The final conclusion was making a Contract to commence 1st October 1780 to supply new Hoops for the service of the whole Navy to be delivered at the Port of Portsmouth at £21 per ton... In addition he contracted to deliver one ton of new for two ton of Old.

From Watson-Dundas memorandum, 1790

The hoop suppliers retaliate (the story goes) by making every effort to raise the price of iron.

Mr Cort verily believes every art was used to raise the price of such Iron as was most proper for Hoops and various obstacles thrown in his way… The whole sum which appears by then to have been lost and expended in and about this Contract was not less than about £10,000.

From Watson-Dundas memorandum, 1790

It may be unfair to blame the suppliers entirely. The cost of their imported raw material has been substantially increased by the exigencies of war.

Here is one source of nineteenth-century theories that Cort was the victim of conspiracy. Yet it is the conversion of old hoops to new that gives Cort ideas for developing his new processes.

Contract Agreed this Third day of May 1780(?) with the Commissioners for Victualling His Majesty's Navy for and on the behalf of His Majesty by me Henry Cort of Gosport in the County of Hants Ironmonger, and I do hereby bargain and sell to His Majesty, and oblige myself to deliver into His Majesty's Stores at Weevill, or on board any Vessel at my Quay at Gosport as shall be required, free of all charge and Risque to His Majesty after the twentieth day of Nov: next during the present War, and further until six Months Warning shall be given on either side, all such quantities of good new milled Iron hoops as shall be demanded by the said Commissioners or their proper Officer of Officers, of such lengths as their said Officers shall give me notice of not exceeding nine Feet long. And I do engage that all the hoops that shall be furnished on this Contract shall be good Milled Hoops of fit Sizes, and wrought of the best Sweedes or Government Siberia Iron, or iron of equal Quality and Goodness, and mark'd with a broad Arrow and likewise with the two initial Letters of my Name by the Rolls, and in case any of the said Hoops shall break in driving I do oblige myself to change them weight for weight; And if the said Hoops shall run of a greater length that nine Feet I do agree that the said Commissioners shall be at liberty to cause such part of the said Hoops to be cut off as shall exceed the said length, And I do also oblige myself to take back such Surplus length cut off as aforesaid, and to return new Iron Hoops in the room thereof weight for weight; And it is hereby agreed that I am to be paid for the said Milled Hoops at the rate of Twenty one Pounds per Ton by Bills made out for them on delivery of each parcel if required, during the present War, adding thereto all the Discount of the said Bills above Five per Cent; And for what Hoops shall be delivered in time of Peace Twenty Pounds per Ton by the like Bills, but no Discount to be added, which Bills are to be paid in the Course of the Victualling with Interest at four Pounds per Cent after six Months from the Dates thereof, And if the said Commissioners shall have any old Unserviceable Iron Hoops in the Store at Weevill, or shall think proper to bring any from other Ports and deliver them at my Quay at Gosport, and deliver one Ton of new Iron Hoops in lieu of every two Tuns of old Hoops that I shall receive. And I do oblige myself to procure two able and sufficient Persons such as shall be approved of by the said Commissioners for their proper Officers to be bound with me jointly in a Bond to His Majesty of Five Hundred Pounds for the due and well performance for all and every the clauses and conditions of this Contract.

And I do also agree that in case of my failing, to deliver the aforesaid all such Quantities of Milled Iron Hoops as shall be demanded of the sort and goodness beforemention'd, that in either of the said Cases, it shall and may be lawful of the said Commissioners or any three, or more of them, to buy either by Publication, or by Order to their officers without Publication, all, and every such Quantity or Quantities of Iron Hoops, as I shall fail to deliver with respect to time or Quality, as aforesaid; and if the Iron Hoops which shall be bought by either of the said Methods, shall cost more than the Price stipulated in this Contract, I do agree that it shall and may be lawful for the said Commissioners for any three, or more of them to stop and abate from any Bill or Bills made out or to be made out to me on this or any other Contract, the full Sum of what the said Iron Hoops so bought shall exceed the said Price; & if thereas paid be no Bill or Bills made out, or to be made out to me then I do oblige myself, my Heirs, Executors, Administrators or Assigns, to pay and make good the same to His Majesty; and I do further oblige myself that before the receiving a Bill for the Iron Hoops delivered on this Contract, or before the last Bills if more, that one be made out to produce my Affidavit, that I have not then given, or will afterwards give or cause to be given to any Officer Clerk or Instrument concern'd in the Receipt of Stores employ'd under the said Commissioners; or to any Person or Persons on their behalf, any Money or other thing, as a Gratuity, Fee or reward, for favour in or relating to this Contract, upon the Penalty of Five Hundred Pounds, incase of my Failure in any Part thereof. In Testimony whereof I have hereunto set my Had and Seal the day and Year first abovewritten.