Help!!

In July 2019 my grandfather gave me his passed fathers watched a truly proud moment for me and I believe a vintage and beautiful watch! However none of us are sure exactly how old the watch is and so I wondered if anyone could help or even give the model as the closest I know is an automatic omega Seamaster and by the sound of it that’s just about every omega watch minus the auto!
Here are the pics. Thanks

new non genuine strap as my great grandfather had it replaced with an identical one to mine I believed it was best to stay totally in style.

Unless your dad had the watch serviced, you will want to before wearing the watch. It might be working fine, but if it hasn’t need serviced in the last 5 - 7 years or so, the oils will be drying up and causing damage. Where was I going with that... oh, get some photos of the movement and inside of the caseback when the watchmaker has it open. Let us know where you are at if you need a recommendation for a watchmaker in your area.

Enjoy the family heirloom!

I think it’s closer to 1959 given the small-hippocampus case back. 2846 reference with probably a 501 caliber movement.