Review: Sea-Gull 816.351 / ST2130

Today, I’m moving up the ladder of Chinese watches. I’m taking apart my beloved Sea-Gull 816.351. This is my everyday watch, and I absolutely love it. I’ve regulated to be 2 seconds fast during the day when I wear it, and then I put it face up on my bedside table and it loses 1-2 seconds overnight. It does this constantly, so the movement must be quite good!

The looks are almost identical to the Sea-Gull M177S – with slight differences of the dial and of course the metal wrist band. 

The watch came in a nice red box, with instruction manual and a price tag in Yuan! So in China, this watch costs around £ 240, I paid £ 300 + £ 60 VAT upon import. So almost 5 times the price of the M177S.
This watch has the ST2130 movement, which beats at a hearty 28,800 bph / 8bps. That alone does not say anything about the quality of the watch – if you have such a fast moving movement, you need the precision of execution to go along with it to make a good watch. So time to open this one up and take a close look at the inside.

The case back is held in place by 4 M1 screws, which are easily removed. Here, you can see the rubber seal, the watch back and the pressure ring that holds the movement in place

The release pin for the winding shaft if accessible through a small hole in the barrel bridge - you can see it on the top left of the crown wheel

I really like the dial of this watch - it's lovely how it reflects the light. The second hand is beautifully made and sweeps across the dial with 8 tiny steps per second

This is the ring that holds the movement in place. It holds the movement with 2 case screws. Very nice execution - compare that to the plastic ring of the M177S...

A detail of the case - nice execution!


A piece of paper with a slit cut into it protects the dial when removing the hands with a hand remover

The second hand with a hair for size comparison

The dial is held in place by two sickle-shaped levers that can be pushed open with a screwdriver

The movement and the dial

Case and dial are moved to the side to prevent damage. I put the dial under the case to protect it

The movement in all its glory. I like the brushed finish of the auto-winder. You can see one of the two black screws that hold the auto-winder in place. The polished screw at the bottom right of the winder assembly is the transmission wheel screw, which will be remove after the winder is taken off

The movement with the winder removed

The winder assembly, which I won't take apart

The transmission wheel with the click. Time to wind down the watch. I've inserted the winding shaft and to put a bit of tension on the transmission wheel - this lifts the click, and I insert a sharpened pegwood stick to keep the click off the transmission wheel. Then I can slowly let the spring down by letting the crown slip through my fingers (don't go too fast...)

I've removed the screw that holds the balance cock, and lifted it slightly with a screwdriver inserted into the side ready for removal

The balance wheel under the microscope

I've removed the transmission and barrel wheel. Careful with the transmission wheel screw - it opens clockwise, as single transmission wheel screws do. Once the wheel is removed, you can see the click spring. Note that it has a longer side, and carefully remove it. You don't want that to drop out of the plate!

I've removed the third & fourth wheel bridge, and you can now see the pallet bridge and escapement wheel

All briges and the crown and castle wheels removed

The escapement wheel with focus on the pinion

The pallets - nice finish!

Castle wheel at the top, crown wheel at the bottom

Time to turn the watch around

The two small plates that hold the date mechanism in place are removed. I will have to give this some attention upon putting the watch back together as the date ring did not always snap properly into position

The bottom plate is now visible

Some odd chipped marks on the bottom plate. Doesn't really affect anything, but I'd rather not see that

Detail with 2 jewels seen from the top plate

Watch parts on a piece of paper, grouped by assembly and ready for cleaning. Pithwood for cleaning arbors and pins on the top left, pegwood stick for cleaning jewels on the right

This time, I will split teardown and assembly into two posts. This one is really about looking at some details of the movement – the assembly will be about cleaning, oiling, etc.

Overall, you can really tell that this movement is one up from the standard 21,600 bph chinese movements. I merits the higher pricetag. The wheel arbors and wheels are better executed and polished, and the overall execution of all the parts is better. The movement looks as though it can take the 28,800 bph.

I’m very happy having paid £ 360 incl. tax for this watch and I will continue to wear it proudly – in a couple of days when I have put the watch back together.

In the meantime, all parts will go into screw-top small glass jars (I use small jars that used to hold lumpfish caviar – they are ideal), so they won’t collect dust.

Click here for the reassembly of the watch.

10 thoughts on “Review: Sea-Gull 816.351 / ST2130

  1. Hello.

    I am a total beginner in the mechanical watch scene. I am familiarizing myself with the basic work horse movements such as ETA2824, Seiko 7s26. Naturally, I became familiar with Sea Gull’s ST2301 and found your page.

    May I make a request for you to review this watch? (

    From my research, it seems like the movement is a variation of ST2301 that Sea Gull is producing. But I can’t seem to find any technical reviews. It’s also hard for me to tell if it is indeed ST2301 because of the modified chassis design.

  2. How fascinating to get a properly expert and educational watch review instead of the usual subjective drivel. Well done!!! – thank you!

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  4. Great review, Congratulations!
    I have the same watch from 1 year. Two summers I use the watch when I swim and diving in sea till 3 meters.
    The inside is still dry 🙂 Do you have some detailed picture inside the crown, I wonder what kind of gasket seagull use?

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  8. Sir
    Well well done. Yes I agree the ST-2130 and the totall Sea-Gull package is excellent. I have been running Sea-Gull Premium Movements (which this is one) for many years and no problems. I think our Swiss friends had better lift their game.

  9. Pingback: Teardown: Sea-Gull 816.351

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