Here is a really unusual one, likely in the "hen's teeth category" Yellow gold plate with stainless back dated 1957. Case back fits against the front of the bezel with a gasket between the caseback and crystal, completely encompassing the movement with split stem and is held in place by 4 pins; one next to each lug. It seems that when the pins are removed, watch is dis-assembled by pushing on the crystal and everything comes out housed in the case back. I haven't attempted to dis-assemble it for fear of doing damage or losing the flat head pins.
This unusual case appears to have only been produced in 1957, but used until 1959 for the Surfmaster, Bulova 23 "U" and in 1959 for the Commodore. The only known examples of this case are all dated 1957 and movement dates from 1957-1959. See my research below.
This example appears to have never been taken apart, and shows no signs of extended wear. Band is a replacement. Running and currently keeping near perfect time.
1957 Surfmaster "B"
Ad is from 1957 Linebook BAWDO131






My random thoughts after extensive research on this unusual pinned case waterproof model:
Surfmaster "A" - Shadow X dial w/sweep second hand
Surfmaster "B" - White dial w/sweep second hand
Surfmaster "D" - White dial w/subseconds
I've yet to find confirmation of the "C" variant. Bulova may have left the "C" slot open, and never produced a shadow dial subseconds variant. The first mention I find in the line books is 1957 for the Surfmaster "A" and "B". By 1958, the sweep "A" is present and "B" is replaced by subseconds "D". It is interesting that we have two "D" variants in the database, and both are dated 1957. "A" and "D" variants lasting apparently until the Fall 1959 release, when these two models also disappear.
In Fall 1959, the "D" variant appears to be rolled into the Commodore line as BW and CW (strap determining variant). It is possible that the "B" variant case/face was also used for the Bulova 23 "U" with an upgraded movement. No further sign of the Surfmaster "A" or "B".
It seems Bulova was experimenting with improved waterproof case designs in 1956/57, as seen in the Surfmaster, 23 "U" and Albatross. Apparently these new designs were quickly abandoned.....
In reply to My random thoughts after… by neetstuf-4-u
Hi there, I have a very similar watch to yours. It is pretty much identical only it is Self Winding and 23 jewels. This is inscribed on the face. It was my late fathers. The identification is a C7 indicating that it was manufactured in 1957. I’ve been trying to get as much info on this watch over the last few years. It was given to my dad as a service award, I believe 25 years. He wore it from 1957- 1963 when he passed away. I’ve had the watch for many years but have never used it. I’m presently looking to restore it somewhat. The crystal had been broken and replaced with a plastic one and the hands are not original as a result of the broken crystal.
it seems that these watches are rather rare.
In reply to Hi there, I have a very… by Peter LeBlanc
In reply to One more thing, it’s L7 not… by Peter LeBlanc