Here's the deal with using Oak in a Marine Environment. If it's White Oak, it's ok cuz it has it's own built in preservatives and has been used in boat building for centuries. Red Oak on the other hand is NOT a good hardwood to use for the Marine environment. Having said this, the OTR will "Do it's Thing" on any wood. Technique is the same. Apply liberally until the wood seems to have soaked it in and won't absorb any more. Let it dry for 2-3 days and then apply 2-3 full strength coats of urethane. What are you intending to use the oak for??? If it's for a "Finish" environment, I'd choose a different wood. If it structural, I'd ask Why??