Quick answer: A tide clock movement is a quartz mechanism designed to show the approximate stage of a semidiurnal tide cycle. Instead of completing one dial cycle every 12 hours, the Heng-Rong HR1688TT is based on a cycle of 12 hours, 24 minutes and 48 seconds. After it is calibrated to a reliable local high-tide time, the tide hand progresses through HIGH TIDE, FALLING, LOW TIDE and RISING positions.
A tide clock is a convenient visual reference for coastal homes, shops, gifts and DIY projects. It is not a live tide sensor and must not be used as the sole basis for navigation, fishing or any safety-critical decision.
What does a tide clock movement measure?
A standard clock movement tracks civil time. A tide clock movement represents the repeating interval between two successive high tides in areas where the tide is mainly semidiurnal. The HR1688TT uses a dedicated gear train to move the tide hand through one full cycle in approximately 12 hours, 24 minutes and 48 seconds.
The movement does not receive real-time data from a tide station. Its usefulness therefore depends on two things: correct initial calibration and whether the local coastline follows a reasonably regular semidiurnal tide pattern.
Verified HR1688TT specifications
| Item | Current product information |
|---|---|
| Model | HR1688TT quartz tide clock movement |
| Tide cycle | 12 hours, 24 minutes and 48 seconds |
| Power | 1 × AA 1.5V battery |
| Tide adjustment | Dedicated tide calibration knob on the back of the movement |
| Hand system | Solar-shaft / Youngtown-type fitting |
| Intended use | Decorative and trend-reference display for suitable coastal locations |
How to calibrate the HR1688TT tide clock movement
Choose a reliable local tide source. Use an official or otherwise dependable tide table for the nearest relevant coastal station. Note a recent or upcoming high-tide time.
Install the battery correctly. Insert one AA 1.5V battery. During setup, keep the battery compartment facing downward.
Wait for the reference time. At the selected local high-tide time, use the tide calibration knob on the back of the movement.
Align the tide hand. Turn the back calibration knob until the tide hand points to HIGH TIDE on the dial.
Verify the reading. Compare the display with the same local tide source over the next cycles. Recalibrate if the reference point was entered incorrectly or if the local pattern does not match the movement well.
The back calibration knob changes the tide phase only; it does not adjust the regular hour and minute hands.
When should the movement be recalibrated?
Initial calibration is required before first use. Check the tide display again after replacing the battery or moving the finished clock to a different port or coastal area. As a practical maintenance routine, compare the display with a reliable local tide table every 6–12 months and recalibrate immediately if the deviation is more than 30 minutes.
Where does a tide clock work best?
The HR1688TT is designed for coastal regions dominated by a semidiurnal tide pattern-typically two high tides and two low tides per lunar day. It can provide a useful approximate trend display in these locations after correct local calibration.
Its readings may be less representative in inland lakes, far-upstream estuaries, mixed-tide regions, locations with very small or extreme tidal ranges, and waters strongly affected by local geography or weather. Monsoons, typhoons, wind and atmospheric pressure can also shift actual water levels and tide times away from a fixed mechanical cycle.
Hand compatibility for product assembly
The HR1688TT uses a solar-shaft / Youngtown-type hand fitting. Current confirmed hand-interface dimensions are:
Hour hand: 5.03 mm copper bushing or 5.00 mm drawn tube
Minute hand: 3.17 mm copper bushing or 3.14 mm drawn tube
Second hand: 0.78 mm
Seiko-shaft hands are not interchangeable with this fitting. Buyers should confirm the hand hole, shaft style, dial thickness and hand clearance before approving a sample or placing a bulk order.
Buyer checklist before ordering
Confirm that the destination market mainly has semidiurnal tides.
Identify the local tide station customers should use for setup.
Specify dial thickness, center-hole size and required shaft length.
Use compatible solar-shaft / Youngtown-type hands.
Check hand clearance above the dial and below any front cover.
Explain in the finished product instructions that the display is an approximate reference, not a safety instrument.
Frequently asked questions
Does a tide clock show live tide data?
No. The HR1688TT follows a fixed mechanical tide cycle after the user calibrates it to a local high-tide time. It does not receive live measurements or forecasts.
Why is the tide cycle longer than 12 hours?
In a typical semidiurnal pattern, successive high tides are separated by approximately 12 hours and 25 minutes rather than exactly 12 hours. The HR1688TT product specification uses a cycle of 12 hours, 24 minutes and 48 seconds.
Can the tide hand be adjusted without changing the time?
Yes. The dedicated tide calibration knob on the back adjusts the tide phase and does not affect the regular time hands.
Should the clock be recalibrated after moving it?
Yes. A different port or coastal area may have a different tide phase and local pattern. Recalibrate the movement using a reliable tide table for the new location.
Can this movement be used for navigation or safety decisions?
No. Use the display only as a decorative or general trend reference. Always consult official tide forecasts and local safety information for navigation, fishing and other safety-critical activities.
For current tide movement options and customization discussions, view the Heng-Rong tide clock movement range or send your dial, shaft and hand requirements through the contact page.
Written by Liz. Technical basis: Heng-Rong HR1688TT product manual and the company knowledge base confirmed in August 2026.