Sloop of War
A military vessel obtainable through capture roughly equal to a Brig in specifications and capability.
(Sorry I did not note unupgraded specifications.)
When upgraded sail 'red' angle is 46 degrees, quartering speed is 12.1kn, running before the wind is 11.4kn, sail strength is 97, crew are 87, cargo is 3052, hull is 136, cannon are 16+4, boarding is 3. That is with full upgrades, except ram, BUT does not have upgrade options for stay sails, close hauled 1 & 2, or square sails.
So its tougher than a corvette, carries the same cargo but less crew and fewer cannons.