I am preparing to re-install my rudder tube (and re-built rudder).

The seal at the thru-hull had failed; Luckily the fitting is only a few inches below the waterline and the compartment where it enters the hull has a water-tight bulkhead.

The failure seems to be due to hydraulic leaks from the steering gear. While on the hard the seal that failed had a pool of hydraulic fluid around it and some was seeping through to the outside of the hull.

The original sealant seems to be clear silicone; Most of the fittings on the boat are bedded with this and it seems to have worked well.

What I am worried about is that the fiberglass around the thru-hull seems to be saturated with oil. I scraped off the silicone, washed, de-greased and wet sanded the area. But, there still seems to be oil in the glass.

Any advice or ideas on products or procedures would be appreciated.

Cheers,
John.