Here is a brief overview of Longines' waterproof, 13ZN references. I might be forgetting a couple but we can add them later.

Waterproof 13ZNs are among the most valuable, vintage Longines. As such, one must exercise extreme caution when assessing authenticity and originality. This is especially true for references 4270 and 4974 where fake cases are known to exist. This thread is not intended to serve as a guide for identifying fakes, it is simply a summary.

The first, as far as I know, is reference 4270. The back is pressure-fit and the pushers have a unique design (patented in 1938). The diameter is around 37.5 mm.

Source: http://www.db1983.com/our-archive/longines-13zn-mushroom-pusher-1939





Next is reference 4813. Again, the back is pressure-fit but the pushers are now in a more familiar style. The diameter is around 35 mm.

Source: https://www.carsandwatches.com/watches



Next is reference 4974. The back is now screwed to the mid-case and the pushers remain in the familiar style. The diameter is around 37.5 mm.

Source: https://www.phillips.com/detail/longines/CH080319/25



Next is reference 5415. The back is pressure-fit and the pusher remain the same. The diameter is around 37.5 mm. This reference also comes in gold with a screwed-back.

Source: https://omegaforums.net/threads/1948-13zn-longines-chronograph-seeking-info.68950/#post-867928





Source: https://watchnet.co.jp/en/





Possibly the final, waterproof reference is 5699. The back is screwed to the mid-case and the pushers remain the same. The diameter is around 39.5 mm. This reference is notable for having a heavily modified movement to accommodate a central, chronograph minute hand and a 12 hour counter at the 3 o'clock position.

Source: https://www.monacolegendauctions.com/auction/exclusive-timepieces-15/lot-51





An oddity that I will include is reference 4270. I only know of one that has surfaced and I have not seen an extract from Longines, confirming its legitimacy. The case is allegedly 18K gold. If I recall correctly, the back is pressure fit.

Source: https://www.instagram.com/p/pjxk-1i5gF/


Hopefully, this was of interest to some.

Edit: I added photos of the inside of case-backs where possible. Note that the back of the ref. 5699 has a separate piece, that normally sits around the movement, sitting inside it in the photograph.

 

Yes, very interesting and look at this beautiful watches!
To add ref. 3504 and here are pictures:
Interesting "case back opener" with two ears!
Source: https://gramho.com/media/2370279078400628019

 

To me, the watch above looks like a ref. 4813. Looking at another example of ref. 3504 (see below), the case is not waterproof and of a completely different style. I would guess that the movement in the watch above is not correct.

Source: https://www.phillips.com/detail/LONGINES/CH080016/86



Source: https://www.shucktheoyster.com/longines-13zn-vintage-stepcase-chronograph/

 

OK, the watch I posted is also illustrated in the Goldberger book and is announced as a "waterproof chronograph" and archive extract says ref 3504.
Don't know if they are not right in the book?

 

According to OP of this thread

https://omegaforums.net/threads/my-grandfathers-1938-13zn-mono-pusher.107001/

This monopusher non waterproof has been confirmed a ref 3504 by Longines

 

Yes, archive extract for the serial number (and movement) corresponds to ref. 3504 but the case is not original to the movement. Not only is the watch in a book, but it sold for >100K CHF at auction. Unfortunately, neither of these accolades make it correct. Below is another ref. 3504 in gold. One can see that this example, like the monopusher and steel piece that I posted above, all have flat, "stepped bezels" and are non-waterproof.

Source: https://www.ebay.com/itm/C-1943-Vin...179608?hash=item548174f8d8:g:~WYAAOSwPf1ec2GHPurchases made through these links may earn this site a commission from the eBay Partner Network

 

It would not be the first published frankenwatch

 

Obviously, the knowledge here is fantastic. And it’s great to see such lovely examples of Longines’ history. But the prices that these currently sell for essentially limits them to a handful of potential collectors. They are, for the vast majority of ordinary mortals, unobtainable and that seems like a real shame.

 

@Rumar89 Indeed, these are way out of reach for most people. But the connection between these references and _______ Longines, for example, is tangible. And some _______ pieces can still be had for relatively reasonable prices. But you are right, this thread is primarily about history rather than practical advice.

 

Thanks for teaching lessions. I appreciate very much your knowledge and I share the opinion that these splendid watches are unfortunately out of reach. So there are lots of time-only Longines out there which are worth to have a look at.

 

I realize this is sacrilege on the Omega forum, and seriously inside baseball, but It would have been much more interesting for Swatch to revive the 13zn or 30ch than the 321.

 

This one just sold for EUR 40k (excl. 31% fee) at Boule auctions

Description:
An ultra rare & exceptional stainless steel chronograph, massive monobloc case, stepped polished bezel, waterproof snap-back case & mushroom pushers, fixed bars. Very nice patinated silver dial, outer tachymeter and telemeter scales, minute track, luminous dots, Arabic numerals and indexes, blued steel hands, permanent seconds & 30mn counter. Manual winding movement Cal. 13ZN, flyback function. With its extract from the archives. Engraved 2160 34 on case-back.

 

40k for this redialed watch ? Not really, even if the case is wonderful and the dial looks nice too, but a redial is a redial.

k

 

If people sell just two pusher for 15k a complete watch with refinished dial seems to be a bargain ?

 

Oh yes, this whole watch is really a bargain! What the hell are my thoughts about that?

 

Well somebody may need this pushers because this 2010 just sold in France. Estimate was a bit conservative . No clue what it sold for https://www.gazette-drouot.com/lots/23292465-longines---montre-bracelet---

 

It was sold for 47k plus around 30% fees

 

@Mark020 You were bang on!

 

About missing 2 zeros