Bruce, I suspect or suggest resealing the bow pulpit, cleats, fresh water filler and any cockpit drain. I bet it will be one of those. I doubt the hull to deck joint as that generally is sealed together with 5200. I would still suggest hosing down each individually first with the help of a friend and you may need to use cell phones to communicate with if you cannot hear from above. Remember the boat is a 1996 or over 20 years old and caulk does not last a life time which is a maintenance item. I would start with that sir. thanks for the photos as it helps to refresh my memory.
If that does not help, the close off the boat, tape down hatches and possible windows. YOu will need then to cover the companionway with plastic taped down, slit it to insert a leaf blower and turn on. You are in a sense pressurizing the cabin. Have a bucket of good soapy water and brush and have a friend brush every fitting with a brush and where air bubbles are coming out, there you will find a leak. Hope this helps.