Cort recorded that his hammer weighed 5 Cwt and made 100 drops per minute per minute from a height of 20 inches.The waters of the Meon were made to work hard turning a number of mills, but the iron mill was the largest. You can still see the mill pond on the other side of Iron Mill Lane.

The following letter reveals that Cort was less well informed on physics and neither was his team:

To: Boulton Esq

in the care of Mr. Tho. wilson
Chase Water near Truro, Cornwall

Sir,
I have recd a Letter from Mr. Henderson, wherein he asks several Questions relative to my Mills, & to which he requested me to give Answers to You, & that you would be Oblidgeing as to give me Your Advice.

My Mill is Undershott
The Diameter of the Wheel 12 1/2 feet; Fall of Water 6 feet
Width of Sluice on Penstock 3 feet & when drawn to its full height is 14 Inches
The Pond when full is 8 feet (deep)
Wheel makes 25 Revolutions per Minute
Weight of Hammer 5Cwt lifts 20 Inches & makes 100 Strokes per Minute

It is impossible to make it Overshott, as it would Drown the Mill above, & if the Banks were raised it would not Drive the Hammer to do any Business, for there woud be only 4 feet head, & now there is 8 feet head & the Bellows woud go longer than the Hammer, so say my Millwright-but that to your better judgement.
If you can make any Improvement I should be glad to acknowledge the Obligation You may conferr on [me]

Sir, Your most obed Servant
Henry Cort
Gosport
27 November 1779

In his letter he says that to make his mill overshot (experiments on showed that overshot wheels are the most efficient although the bottom needs to clear of the water)it would drown the mill above. The 'mill above' would have been Little Funtly Mill, we hear that it was unable to live with Cort's mill and closed anyway. The total heads of all the mills on the river course must not exceed the fall of the river itself from where it rises to its estuary. The power generated by a mill is measured in foot/pounds per minute, so an increase in the weight of water (size and number of buckets) might have been the solution. Another possibilty was a second wheel, but there are no signs of this on available maps.

Tilthammers were powerful machines, they turn the peaceful trickle of water into a thundering beast that must have been the curse of the neighborhood. They did have a major flaw in that since the hammer fell freely in a radius, when the job was loaded on to the anvil it was at its thickest so the hammer would have less time to gather momentum, as the work was compressed the blows got heavier. The workplace was therefore equipped, with interchangeable hammer heads and anvils.