Southwark, Decem 16 1793

Dear Sir

 I think it necessary to inform you in what manner the Tonage is calculated that I have made

the Estimate from.

 In the first place to find the length of draught rabbit forward you take 3/5 of the Beam as

usual; from that point to the after part of the Stern post allowing its width measurement not to exceed 1/12 of the Beam. That length being determined, you then multiply it by the length of the Beam, & that product by the height of the gundeck Beams amidships on the top of the Beams, added to half of her waste amidships which last product divide by 95 which gives the number of Tons Required.

                                                   I am Respectfully yours Sir
                                                                   Joshua Humphreys