Seagull Caliber ST17

Manufacturer	Tianjin Sea-Gull
Caliber Number	ST17, ST17XX, TY27, TY27XX
Movement Type	Automatic or manual-wind
Diameter	26mm
Height	Varies
Jewels	Varies
Beat Rate / Frequency	21,600 bph / 3 Hz
Power Reserve	~38 hours
Anti-Shock System	Incabloc clone
Hand-Windable?	Yes
Functions	Central hours; central minutes; small seconds at 6:00; date depends on caliber
Hacking Seconds?	No
Country of Manufacture	Made in China

The Seagull caliber ST17 (aka TY27XX) is a line of small-seconds watch movements made in China.

You’ll notice no engravings or inscriptions on the movement or rotor. No branding, not even a jewel count.

Tianjin and Seagull are the same company (Tianjin Seagull Watch Group), but they have offices in Tianjin, China as well as Hong Kong. Apparently the different caliber numbers correspond with where the movements ship out of.

ST17/TY27 Variations:

• ST1700 / TY2705 – Manual-wind
• ST1701 / TY2706 – Automatic, no-date
• ST1731 / TY2718 – Automatic, date

Additional Resources:

• Tianjin Seagull on Wikipedia
• Mentions of Seagull on Caliber Corner