Oil v. 'thane.
There are a couple of issues in your query.If the Admiral loves the oil finish, stick with it. I have to suspect that you are not making the best choice of products though. Most teak oil sold in marine stores is crap. It is so diluted with thinner, in order to keep the price down, that you might as well be wiping down with mineral spirits. If the product comes in a clear bottle, shake it, the junk will actually foam. I can't recall the brand, but BUS carried one that was not their most expensive and didn't foam...still, too thin to suit me. A good grade of Tung oil typically has natural polymers (sometimes added) that will harden. The 'gloss' finishes aren't glossy but do contain more solids and will build up on the surface. An oil finish should last a couple of years, at least, on a boat without requiring renewal. I make furniture as an avocation and prefer oil finishes. I have pieces that we kept for our home and haven't required renewel in over ten years.Bleaching is no big deal, but is a messy job on a boat. The more teak that you can easily remove and do ashore, the better. Steer clear of the two-part bleaches... they require experience to get an even color. The best bleach for general use is oxalic acid. It is not as fast as the two part products but is much easier to control the color change across differing grains. It is a reducing agent and will not harm wood fibers as chlorine bleach will. Zud and Barkeeper's friend contain oxalic acid as their active ingredient if you have difficulty in getting the straight stuff.Now for the real dirt, I'll tell the horrifying tale of how I refinished the teak on my last boat... a thirty year old Cal-27 T/2. For those gentle souls who quake at non-traditional methods, please tune out now.First, I stripped the cupboards, lockers and entire cabin of every item stowed. This included anything installed that shouldn't be inundated...radio, clock, fire extinguishers, cushions, curtains, hanging decorations, mirrors, floorboards, etc., etc., etc.I then mixed up a batch of bleach with a little TSP in a garden sprayer and spray the entire interior of the boat and let it set while I drink a beer and swap lies with my dockmates. I then use my trusty 1200 psi electric (read..."cheapo") pressure washer set to a fan spray, to thoroughly clean the entire interior including the wood. This is also great for controlling mildew.After it dries, the wood needs to be lightly sanded with 180 grit sandpaper or a green 3M pad to smooth the raised grain. Do not use a finer grit, doing so actually closes the pores of the wood inconsistantly and you will get an uneven color. Now rub down with a high quality, high solids tung oil.