Brass Porthole Tide & Time Clock The brass porthole tide clock measures 8.5"D overall & 5.75"D for the face. This beautiful instrument will accurately predict the tide cycles in your area. It will add a definite nautical touch to whatever room it is placed in and is a must have for those who appreciate high quality nautical decor. It makes a great gift, impressive decoration & will be admired by all those who love the sea.