Sorry to hear about the problems you had with the smell and AC. Especially so because of the nature of your trip.
On our last trip to the BVI’s we also were on a Lagoon the same as you. We noticed the same strong smell and also thought is was coming from the heads. I spoke with BVI Yacht Charters the next day because nothing we did would get rid of it. They diagnosed it as off-gassing of the batteries. They sent a chase boat to Cooper Island with a new battery bank and changed them all out. Problem solved.
I am eternally grateful for their excellent service.
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