Yeah....the brown goo is easy to clean out.

As Capt. Chuck said that problem seems to be the leakage from the two storage boxes at the transom. When I did my transom the area where the engine is mounted was fine, however about an 18" x 18" area around the drains on the boxes was real easy to clean out.....a big screw driver cleaned it perfectly with no effort. My worry was from the dive ladder bracket mounted in that area, when you would put pressure on it the transom would flex in about 1/4" to 1/2" and you could hear the crackling of fiberglass, not good.