Accidentally Left Crown Unscrewed

[Dirt]

Originally Posted by sjhoppes

I think my concern is mostly from my lack of understanding on how the crown works. I didn’t know if it needed to be screwed in for the internal gaskets to be tight for the water resistance or not. Sounds like from everyone that this is not how it functions.

Good question and one will get varying answers.
Naturally, it's a given the manufacturers will always say that the crown should always be in the screwed down position as that's basically how it's all intended to work.

When we look at the cut away models of all the designes, the only one that has no obvious crush type of seal is the daytona pusher which is designed for a 100 m water resistant watch.
The HEV will naturally be more water resistant the deeper it goes under water as the pressure increases and exerts more crush on the outer seal.
The Triplock has an external O-ring which comes into play when the crown is screwed down. Though it's well understood that the internal O-rings form a significant part of the effectiveness of the design.
The Twinlock clearly has a crush seal up inside the crown which is squashed down onto the end of the Crown tube when fully screwed down.

It's important to note the Rolex ran an advertising campaign way way back in the day, which showed how effective a Twinlock can potentially be at keeping water out.
Keep in mind that the early Submariners originally were designef with Twinlocks with some being upgraded at Rolex service to a Triplock when it became available for that reference.
Anyway, the advertising campaign showed a picture of the 100 m water resistant watch which had stopped working due to deformation of the caseback against the movement at extreme depths. Notably the watch had a Twinlock crown that was left open for what was intended as a destructive test and no water entered the case during the test.

We can reasonably assume that the internal seals on the crowns and pushers are rather effective when everything is in good order.
Though i remember one poor fellow on this forum with a new Deepsea that was getting moisture inside the watch after being in a hot tub.
Rolex fixed it under warranty after a few trips back to them to find the cause, which worked out to be a faulty HEV that didn't show up as being the culprit on initial testing.