I volunteer!
It's a SEAmaster, not a SHOWERmaster, so you are probably screwed. Seawater has sodium content, and the negative ions form a protective barrier on the case of the watch -- sort of a force field if you will, that keeps out the water. That is why you can easily get Seamasters rated to depths of 300M. They don't even need much in the way of gaskets, as the deeper the Seamasters go under, the stronger the resisting barrier of the seawater ions grows. But when you shower, it is usually with fresh water, so all of the advantages of a Seamaster are lost. In fact, you are extra screwed if you wash with shampoo and soap, as that makes the molecules of fresh water slipperier, and the water will slide right into the case. Showermasters do not rely on the force-field mechanism that Seamasters use, and are designed by Omega to resist the influx of slippery water molecules. This all explains why an Omega Seamaster rated for 300M depths is understood by many to not be safe to wear when washing one's hands, because it offers no resistance to slippery water molecules. and let's not forget about the additional kinetic forces introduced by the shower head, of the vapor pressure from the steam.
Moral of the story? Showermasters for showers, and Seamasters for swimming/ diving in the sea.
j/k -- I hope the watch is okay. Not because of the stem, but because it may have been 8 years since the seals/ gaskets were checked.
Click to expand...