Smugglers are common in the Caribbean throughout all eras. One could think of them as freelance merchants. They will sail between nations, even in times of war. For example, smugglers will leave a Spanish Port bound for an English one even while they're at war with each other, unlike normal merchants. They will put up some kind of a fight and sail fast ships, such as sloops, or ships of the sloop class. Some will also used brigs or ships of that class, but sloops are more common with smugglers.