THIS IS A LIGHTWEIGHT  DOMESTIC CLOCK NOT A HEAVY MARINE item and is NOT suitable for boats and will not match any barometer you already have.

NEW  a 145 mm diameter x 45mm deep spun brass Time and Tide ships clock. The unit has 4 hands Hour Minute and seconds, the 4th blue tide hand rotates at 12hrs 25 mins to every 12 hrs of the hour hand and indicates the tide rising or falling once set to your location. It can be hung on the wall with integral hanger. 

Note:

 This is a lightweight domestic clock not a HEAVY MARINE Item and therefore not ideally suitable for boats.