The main source for this article provided detail on crew turnover and death rates for her first three voyages.

The main source also provided data for her fourth, fifth, and sixth voyages for mortality rates on the Middle Passage among the enslaved people that she was carrying.

[6] 1st voyage transporting enslaved people (1785–1787): Captain Jeffrey Howlett (or Howlet), sailed from Bristol on 22 July 1785.

Brothers arrived at Cape Coast Castle on 16 September, and departed for Benin four days later.

If one removes Brothers from the calculation, the average death rate drops to a still high 12%.

[9][b] 2nd voyage transporting enslaved people (1787–1789): Captain Howlett sailed from Bristol on 6 July 1787.

In 1788–1789, James Jones, Thomas's owner, had nine enslaving vessels at sea or on the coast of Africa.

3rd voyage transporting enslaved people (1789–1790): Captain David Williams sailed from Bristol on 22 July 1789.

[c] Brothers arrived at Cape Coast Castle on 5 September, and acquired captives at New Calabar.

[17] Dolben's Act also provided for bonuses for master and surgeon for low mortality among the captives carried.

[19] Dolben's Act apparently resulted in some reduction in the numbers of slaves carried per vessel, and possibly in mortality.

[20] 4th voyage transporting enslaved people (1791): Captain Joseph Williams sailed from Bristol on 28 January 1791.

[d] Brothers passed Cape Coast Castle on 28 March and was reported at Bonny in April.

[23] 5th voyage transporting enslaved people (1791–1792): Captain Williams sailed from Bristol on 18 December 1791.

Brothers sailed from Africa on 18 May, having embarked 287 captives, and arrived at Kingston on 3 July with 253; this represented a 12% mortality rate.

[25] 7th voyage transporting enslaved people (1794-loss): Captain James Barr sailed from Bristol on 15 October 1794.