Silva Type 4S combination baseplate/sighting compass

[bgriffith]

This compass belonged to my grandfather, and I'm curious to find out approximately when it was made.  I sent an email to Silva to ask about it but they couldn't find anything about a Type 4S and the best they were able to do was send me the manual for a Model 54, which seems to be a fairly close modern equivalent.  Like the 54, The 4S has a small mirror and a sighting lens in the bezel which gives the functionality of a sighting compass.  It has fewer markings on the base plate than the 54, and the scale at the top of the base plate is interchangeable.  Also, where the 54 has a clear plastic disc in place of a needle, the disc on the 4S is aluminum. 

I don't have a place to upload photos that would let me post them inline here, but I think these links to Google Photos should work:
Overall view of compass: https://photos.app.goo.gl/H4WQvPofZdsrqHVMA
Close-up of markings: https://photos.app.goo.gl/WNovnYWyqPQA4cxG7
View through sighting lens: https://photos.app.goo.gl/DrNHPghjE49oemxA9

I thought maybe the combination of the plastic bezel and the aluminum compass rose disc might help narrow down when it was produced, if anyone happens to know when the transition from aluminum to plastic might have occurred. 

I'd be grateful for any thoughts anyone might have about this compass.

Thanks,
Ben

[boomer]

Be interesting to see what turns up Ben

My Silva is different in several ways but has severed my well fo a long time. Like 40 years.

Good luck and happy trails

[wsdstan]

Hopefully wolfy will see this post.  He knows a lot about compasses and may know about this one.  I had one Silva for years but it is long gone.

Looking at Silva history the company started around 1933.  One of their early achievements was a compass that settled in 4 seconds thus the 4S designation perhaps. 

They started US production in 1946.  There have been some for sale on various Ebay sites in Australia, Europe, and the US but none are currently listed.