I am in the midst of fixing my 30 to make it sea worthy. I have multiple areas where brown staining is occuring. Most of them are locations where the teak wood is attached to the exterior. Removal, inspection and re bedding with butyl tape is my plan. Those areas where there is no teak, the leaks are clear water, doesn't mean to say the core isn't affected. As a helpful hint, when re bedding using butyl tape, campfer hole to stop spidering and allow the butyl tape to seal in a cone style shape. Just my two cents.