Kester has pre-empted some of my reply, so I don’t need to comment on who may or may not be odd around here!
I think the explanation for Able Seamen in Nelson’s retinue may be even simpler. I think that men’s ratings listed in the muster really had only one function – to determine what they were paid. A man’s rating in the muster might not reflect his actual duties on board. Until 1794 a rear admiral was allowed a retinue of fifteen servants. But from 1795, admirals were given an allowance to compensate for the loss of most of their servants, and the admiral’s retinue was reduced to five for a rear admiral (twelve for a commander in chief). The retinue of five would include the flag lieutenant, secretary, and his clerk (source; Brian Lavery). Also from 1795 the Admiral’s servants in this reduced retinue were now paid at the rate for an Able Seaman (source: Michael Lewis). Hence, I think, the ratings of AB in the muster. Thomas (Tom) Allen (as Kester points out), rated as Able Seaman in the muster, is usually described as Nelson’s servant or valet, and I think Thomas Spencer was Nelson’s steward.
Presumably an admiral could still bring a larger retinue, but they would be ‘supernumeraries not borne for wages’.
Interestingly, Mira, Tom Allen is occasionally referred to in books as Nelson’s coxswain. In Michael Lewis’s ‘Social History of the Navy’ there is a plate with his portrait captioned ‘Tom Allen, Nelson’s Coxswain’. Elsewhere in the text, referring to another admiral’s coxswain, he comments that an admiral’s coxswain was often also his body servant. Tom Allen’s later life is of course well documented. But it is perhaps possible that the man you are looking for, who was coxswain of Nelson’s barge, was never actually rated coxswain in a muster book.
Brian, you are very likely right that it would have been difficult for the same man to have commanded both the admiral's and captain's barges – it was pure surmise on my part, and I have no knowledge of the usual arrangements. But did a flagship always carry an additional barge for the Admiral? It seems the Victory at Trafalgar did not. According to Peter Goodwin, she carried a 34ft Launch, a 32ft Barge (for conveying the Admiral to & from ship), a 28ft Pinnace (for conveying the officers & general use), two 25ft Cutters, and an 18ft Cutter. Presumably Hardy had to make do with the pinnace unless Nelson didn’t want the barge. Would the Vanguard have carried two barges? She was small for a flagship.
Also it looks to me as though none of the Admiral’s retinue could be rated as Coxswain in the ship’s books, as a coxswain was paid more than an able seaman. According to the Ayshford Trafalgar Roll, there were no ships with more than one coxswain at Trafalgar, despite there being three with admirals on board. Also members of admiral’s retinues were rated Able Seaman at Trafalgar: three in the Britannia, three in the Royal Sovereign, and five in the Victory.
According to Roger Knight, John Sykes was coxswain in the Theseus, and he is described as Nelson’s coxswain, so I do wonder if Captain Miller lost his coxswain to the admiral?
No, I don’t have the muster book for the Foudroyant. The CD I have has the muster books of all the ships at the Battle of the Nile, plus the Master’s Logs for the battle - scanned images of over a thousand pages. It is available here:
http://www.yesteryearsgen.com/ for £19.99 – not bad value.