One longboat from Bristol joined the eight longboats from Providence to attack the English navy schooner. Why were men rowing from Bristol to help in the attack of the Gaspee? 

One longboat from Bristol joined the eight longboats from Providence to attack the English navy schooner.  From the description given by informer Briggs, it seems clear that Capt. Simeon Potter and his group from Bristol knew what was happening. They were rowing to join the attack as part of a pre-arranged battle plan specifying not only place, and the type of ship or boat to use , but also the time for the attack.

It was the middle of the afternoon when Brown could have decided to make the attack.  A man riding a horse could have gotten to Bristol in time to ask for Bristol men to come to the attack by rowing to the Gaspee.  But why do that?  Brown had plenty of ships and men in Providence.

Present day maps show the following approximate rowing distances to Gaspee (Namquid) Point: 

Several possible reasons suggest themselves for the involvement of Capt. Simeon Potter and his boatload of men rowing the 11 miles from Bristol.  The first and strongest possible reason arises because John Brown was the sheriff of Bristol county, not the sheriff of the county of the city of Providence.  Brown may have been prepared to take the position that he was lawfully trying to serve Dudingston with a warrant of arrest in a civil case .  Read theory of attack.  The sheriff of Bristol county should first call on the men of his county of office, Bristol County, as a part of the legal process. A sheriff who had a writ or had a reasonable reason to arrest someone had the right to order citizens to aid him. A Rhode Island statute similar to the English Riot Act gave a sheriff authority to turn bystanders in his own county into a posse.  Brown as sheriff would be hard pressed to say that he was acting as a sheriff of Bristol County to serve a warrant but had not attempted to use a posse of men from his own official county.  Hence we think it most likely that John Brown  asked for Bristol men so as to add more color to his claim of using lawful force.

A reason for Brown to specifically request Simeon Potter of Bristol, a ship captain among many ship captains, to come join the attack would arise if the attack was designed as a claim to serve a Rhode Island warrant or otherwise assert Rhode Island control of the Bay.  Potter was the appointed by the Rhode Island legislature to be the Colonel of Bristol County. That title of "Colonel" had legal significance, beyond being a title of authority in military matters. The royal charter of the Rhode Island and Providence Plantations gave the Governor the title not only of "Governor" but also that of "Commander in Chief" of the Colony.  Governor Wanton's executive agents on the military side of his colonial authority were his Colonels.  Having the Bristol County Colonel plus the Bristol County Sheriff attempting to board the Gaspee would be an assertion of both the civil and also the military authority of Rhode Island over the waters of Narragansett Bay.

A third reason for Captain Potter and his men coming from Bristol could be simply that they wanted to join the expedition and voluntarily joined with the men from Providence.  The me this is a weak reason.  For the Bristol men to join in the attack required coordination that would only come by a discussion, and there is little reason to have men row eleven miles from Bristol to the Gaspee,  when sufficient men were available in Providence only six miles away from the Gaspee.

There is a fourth possible reason for the Bristol group being involved, but it is a week and improbable reason.  If Brown wanted a special detachment of disguised men who were unable to be identified as Providence men, Bristol men might have been used. There is a strong tradition in Bristol that the Bristol men were disguised as Indians.  If (read further) they were disguised either Brown could have requested it or, alternatively, that disguise was the idea of the Bristol men, who had not been issued any special orders regarding the use of disguise.

As to the "if" words used in the foregoing paragraph, there is conflicting evidence that the Bristol men were in disguise.   Willfred Munro, Tales of an Old Sea Port (Princeton University Press: 1917) reports that

"In January 1881, Bishop Smith of Kentucky, born in Bristol in 1794 and a graduate of Brown in 1816, wrote to me calling my attention to a slight difference between the "Swan Song", as I had given it in my History of Bristol, and a version pasted upon the back of a portrait of Thomas Swan's father by Thomas Swan himself. Captain Swan was Bishop Smith's uncle. The Bishop wrote, "I should not have troubled you on so inconsiderable point had not the tradition in our family been that the Bristol boat was manned by men in the disguise of Narragansett Indians."

When Bishop Smith penned these lines several men were living in Bristol who had heard the story from Captain Swan's own lips. He delighted in telling it and was accustomed to give the names of Bristol participants.

However, certainly disguise is counter to Brown's use of open and undisguised men from the Providence boats. Brown and the other merchants were clearly not disguised when they met in lamplight in the Gaspee's cabin to examine Dudingston's documents in the full view of Lt. Dudingston and Midshipman Dickinson.

More likely, the men on all the boats used blackening on their faces only to ensure obscurity of the attackers from the deck of the Gaspee. This is supported by an  interesting document in the Manuscripts Collection of the Rhode Island Historical Society, Gaspee Papers MSS434. The sense of this letter indicates that the Gaspee raiders did not adopt clothing as a disguise, but did blacken their faces, not to disguise themselves as Indians, but to ensure tactical surprise on this dark night in which they were approaching their object silently, without talking and with muffled oars.  The document is a handwritten copy made by a clerk at the Kent County Courthouse ca. 1909 in an effort to preserve historical documents that were deteriorating. The letter is unsigned, but was apparently written by a loyalist spy who (1) lived in the Providence area in June 1772, and (2) was attempting to give the best possible intelligence reports to Admiral Montague. The way the boats and men are described by the spy indicates either self-observation from a little distance, or gathering of information by personal knowledge given him by Providence residents.

Conclusion:  John Brown used Col. Potter and the Bristol men to give color to a claim that he was using legal force to board the Gaspee to serve a Rhode Island warrant of arrest on Dudingston.