It's hard to find good quality teak sealers now days. I used the Semco brand, but found a better TEAK SEALER called Primo Wood Products. Primo Teak Sealer is an easy to use, epoxy resin & teak oil blend that really lasts. This products outlasts Semco by 2 to 1. Try it out
We have been using the product for many years now, typically we apply it 3 to 4 times per year depending on the amount of racing we have done and the amount of rain we have had.
Bow shot is of the natural on my fathers new boat shortly after it was applied to the teak.
The old boat we needed to give the teak a light sand after I think 7 years to get it back to looking it's best. The 2nd pic is the just after that was done.