Conditions like this are waving a red flag. Note that the stringer here is only covered with chopped strand mat. The plywood deck at left is rotting because of water weeping though the stinger, which is also rotted. Next, builders routinely paint wood with gel coat to make it look nice, but looking nice doesn't help much because water goes right through gel coat and gel coat doesn't stick to wood so good. When the wood absorbs water, it swells and the gel coat cracks, allowing in even more water.
Many builders like to paint the wood with gel coat so that it looks like protected.
As you know, water goes right through gel coat, the wood gets wet and swells, which is why you often see all those cracks when you open the hatches. If that's the case, there isn't much you can do to prevent deterioration except to buy a better quality boat next time around. Exposed wood presents an obvious problem that needs to be addressed. This usually means incomplete glassing of parts as shown at right. Unfortunately correcting this after the boat has been built is not easy as such places are usually hard, if not impossible, to reach.