Thank you both for your efforts. In going back to St. Vincent I found the following in chapter 42, George talking about Bacchante;
“I think she looks rather crazed and horny,” Chartley corrected. “And she has large breasts.” They laughed again, and then Granger let his eyes move past her, to the forecastle. The snub nose of a nine-pounder poked out at them, the perfect gun for a bow-chaser.
They dismounted and walked next to her on the dock. “She seems so much bigger than Belvidera,” Chartley observed.
“She is 20 feet longer and five feet wider than Belvidera,” Granger said. “She is rated for 38 guns, so will carry six more 18-pounders than Belvidera does.” They walked back to the stern, where the expansive windows spread across the back of the ship. Her name was emblazoned across her stern.
That would seem to indicate that Belvidera did in fact have 32 - 18pdrs., but with only 30 (15 aside) mentioned as being on the gun deck where would those last two have been located. Unless it was originally a typeo, that was missed. Thanks again, I will keep looking for a definitive answer.
Let us hope that today we find a new chapter posted to the site. Ta ta for now.