Isabel was a comparatively small sailing vessel for the time, a brigantine, which meant at least two masts, at least one square-rigged and one rigged fore-and-aft.
From Lloyd's Register of Shipping 1880:
Official Number : 65863
163 tons, 102ft x 22ft x 12ft
material: o p [ordinary planking?]; metalled in October 1878
Dk & B: 1
Fast'ng: ci [cast iron mooring]
Built in Bridport by Ed in July 1871
Owned by Job Brothers of Liverpool and St John's Newfoundland
Remarks and Place and Date of Special Survey: B D C blw Salted July 1871
[Source: Lloyd's Register of Shipping 1880]
NB Lloyd's wrongly identifies Isabel's Master as W. Sopp. Sopp was master of Mildred - in whom Quick had also sailed - when it arrived at St John's from Pernambuco on 29 July 1879; Isabel, master Quick, had arrived at St John's the day before, from Barbados. I think both vessels were owned by Job Bros.