The Catalpa was a vessel of 202.05 tons net, 90 feet in length, 25 feet in breadth, with a depth of 12.2 feet. She was rigged as a merchant bark, with double topsails, a poop deck, and cabin half above decks. Her main deck was roomy and she had an open hold, there being nothing between decks excepting her beams. The house and galley were on deck, merchant fashion; altogether she seemed a stanch vessel. The bark was brought around to New Bedford and the fitting commenced at City Wharf under Captain Anthony's direction.
Davits and whaleboat gear were rigged, a forecastle was built for the sailors, a half deck put in, sail and rigging pens built on one side and a steerage on the other. Then it was discovered that the riding keelson was rotten, and John W. Howland, who was in charge of the repairs, performed a mechanical feat never before attempted. The foot of the mainmast rests upon this part of the vessel, yet a new piece was put in with such skill that the rigging did not settle throughout the voyage.
The bark was provided with a forward and after cabin. Two rooms on the starboard side were knocked into one for the use of the captain, the mate's room was on the port side, opposite, and the second and third mates were furnished accommodations in the forward cabin.
The vessel was fitted ostensibly for a whaling voyage of eighteen months or two years in the North and South Atlantic. Captain Anthony was given supreme authority in the arrangement of the vessel and in securing the fittings, and gave his personal attention to the stowing of the ship.
On the day of sailing, the vessel and outfit had cost the Clan-na-Gael committee $18,000. The vessel stood in the name of James Reynolds of New Haven, a fact which aroused considerable curiosity among the New Bedford whaling agents, since he was a newcomer in the field which they had regarded as a monopoly.
The conspirators made but one request with relation to the crew. They wished to have one of their number accompany the vessel, and Dennis Duggan was selected. He was shipped as carpenter. Otherwise the responsibility was placed with Captain Anthony, and it was a difficult task, requiring no little discretion and knowledge of the character of men.
He made a wise choice, it will be seen later, in the selection of Samuel P. Smith of Edgartown as first mate. The crew was purposely made up largely of Kanakas, Malays, and Africans, since they were likely to be less suspicious than other sailors and could better endure the climate of the southern seas.
The shipping articles described the crew as finally made up as follows. The names of some of the men were invented and bestowed upon them by the shipping agents.
| Name. | Place of Birth. | Place of Residence. | Of what Country Citizen, or Subject. | Age. | Height. | Complexion. | Hair. | Eyes. |
| Samuel P. Smith. | Edgartown. | Edgartown. | United States. | 29 | 5.11 | Sandy. | Brown. | Gray. |
| Antone Farnham. | Brava. | New Bedford. | Brava. | 43 | 5.11 | Dark. | Black. | Black. |
| George H. Bolles. | New Bedford. | New Bedford. | United States. | 24 | 5.6 | Sandy. | Brown. | Black. |
| Caleb Cushing. | Harwich. | New Bedford. | United States. | 23 | 5.1 | Sandy. | Brown. | Black. |
| Mopsy Roso. | Malay. | New Bedford. | Malay. | 21 | 5.5 | Dark. | Black. | Black. |
| John Roso. | Malay. | New Bedford. | Malay. | 30 | 5.4 | Dark. | Black. | Black. |
| Walter E. Sanford. | N. Bridgewater. | Raynham. | United States. | 19 | 6.0 | Light. | Light. | Blue. |
| Cyrus S. Hill. | N. Woodstock, N.H. | Exeter, N.H. | United States. | 21 | 5.10 | Dark. | Black. | Brown. |
| Antone Ferris. | Cape de Verde Is. | New Bedford. | Cape de Verde. | 50 | 5.8 | Dark. | Gray. | Black. |
| Henry D. Paine. | Woodstock, Vt. | Woodstock. | United States. | 17 | 5.9 | Light. | Light. | Blue. |
| John Coeking. | New Britain, Conn. | New Britain. | United States. | 27 | 5.3 | Light. | Light. | Blue. |
| Edmund F. Gleason. | Candia. | United States. | 30 | 5.2 | Dark. | Black. | Black. | |
| Robert Kanaka. | Hope Island. | New Bedford. | Hope Island. | 22 | 5.7 | Black. | Black. | Black. |
| Mike Malay. | Malay. | New Bedford. | Malay. | 21 | 5.3 | Black. | Black. | Black. |
| Zempa Malay. | Malay. | New Bedford. | Malay. | 21 | 5.2 | Black. | Black. | Black. |
| Lumbard Malay. | Malay. | New Bedford. | Malay. | 21 | 5.3 | Black. | Black. | Black. |
| Gingy Malay. | Malay. | New Bedford. | Malay. | 21 | 5.4 | Black. | Black. | Black. |
| Henry Parrott. | St. Helena. | New Bedford. | St. Helena. | 22 | 5.6 | Black. | Black. | Black. |
| Thomas F. Knipe. | St. Helena. | New Bedford. | St. Helena. | 22 | 5.9 | Black. | Black. | Black. |
| Thomas Kanaka. | Hope Island. | New Bedford. | Hope Island. | 28 | 5.7 | Black. | Black. | Black. |
| Robert Ceil. | St. Helena. | New Bedford. | St. Helena. | 18 | 5.6 | Dark. | Black. | Gray. |
| Joseph Rosmond. | St. Lucia, W.I. | New Bedford. | St. Lucia. | 21 | 5.8 | Black. | Black. | Black. |
| Dennis Duggan. | New York. | 30 | 5.9 | Light. | Light. | Blue. |