Water inflicts the greatest harm on watches, due to the corrosion it causes.
With watches, we no longer use the term waterproof, but instead we use the term water resistant, because no watch is absolutely waterproof. If a watch is water resistant, you will be able to see this somewhere on the watch dial or back cover. If no further details are given, the watch will only be splash-proof.
Schaftenaar Watches models Journey and Traveller are 100 meters water resistant; you can find this on the back cover.
As confusing as it may sound; this does not mean that you can dive 100 meters under water.
How does this work?
If you go under water and you move, this will increase the pressure as a result of which you could exceed the water resistance margin. In salt water, the pressure increases even more, seeing that the density of salt water is higher than the density of fresh water, resulting in reaching the limit even sooner. Keep in mind that the tests for water resistance are done in favourable circumstances.