Us Harbor Tides (2024)

FAQs

Who has the most accurate tide chart? ›

Online predictions are more accurate and up-to-date than what is provided in the annual printed tables. NOAA tide predictions are used by both commercial and recreational mariners for safe navigation. NOAA's Center for Operational Oceanographic Products and Services produce these tide tables on an annual basis.

Tides are caused by the gravitational pull of the sun and the moon on the earth. Along the Pacific coast, there are usually two high tides of unequal height and two low tides of unequal height approximately every 24 hours.

So, it takes the Earth an extra 50 minutes to “catch up” to the moon. Because the Earth rotates through two tidal “bulges” every lunar day, coastal areas experience two high and two low tides every 24 hours and 50 minutes. High tides occur 12 hours and 25 minutes apart.

The highest tides in the world can be found in Canada's Bay of Fundy at Burntcoat Head in Nova Scotia.

Tide Alert is the definitive app for tide and lunar phase information, designed to provide outdoor professionals, maritime enthusiasts, and casual beachgoers with the knowledge they need to align their activities with the rhythms of the tides.

The elliptical orbits of the moon around the Earth and the Earth around the sun have a substantial effect on the the Earth's tides. Once a month, at perigee, when the moon is closest to the Earth, tide-generating forces are higher than usual, producing above average ranges in the tides.

The moon appears full when the Earth is between the moon and the sun. In both cases, the gravitational pull of the sun is 'added' to the gravitational pull of the moon on Earth, causing the oceans to bulge a bit more than usual. This means that high tides are higher and low tides are lower than average.

They occur when the gravitational pull of the Moon and Sun are at right angles to the Earth, which reduces their combined gravitational influence. During low tide, the water recedes, exposing more of the seabed or river bottom, and beaches may widen due to the receding water.

The 50/90 rule states that: We expect zero flow speed as the tidal stream changes direction (slack water) One hour later, the flow attains 50% of maximum speed. Two hours after slack water, the flow attains 90% maximum speed.

Rule 12 - Sailing vessels

Power driven vessels must avoid and/or give way to all sailing vessels when under sail. Ships, tugboats with tows, commercial ferries and fishing vessels have right of way over sailing vessels. Yachts should stay well clear of these vessels.

What is the rule of 12th in tides? ›

The rule states that over the first period the quantity increases by 1/12. Then in the second period by 2/12, in the third by 3/12, in the fourth by 3/12, fifth by 2/12 and at the end of the sixth period reaches its maximum with an increase of 1/12. The steps are 1:2:3:3:2:1 giving a total change of 12/12.

Tides are caused mainly by the Sun and Moon. The Sun and Moon attract the sea by gravitation. When the tide goes out, the water moves to a place between the sun and the moon which is out at sea, away from the beach. When the tide comes in the water moves to a place between the sun and moon which is over land.

In the period between the two spring tides, the moon faces the Earth at a right angle to the sun. When this happens, the pull of the sun and the moon are weak. This causes tides that are lower than usual. These tides are known as neap tides. Tidal Features.

Nearly enclosed seas reach deeply into continents and are connected with the open ocean by narrow waterways called straits. Seas of this type include the Mediterranean Sea and the Baltic Sea. Because such seas are almost landlocked, they have a small range of tides. Some have no tides at all.

The most accurate tidal predictions usually exist for places located on the coast because they are less affected by winds and other meteorological events. Areas with shallow water or in a bay are more affected by alternate factors.

Differences between predicted and observed tides will be greater than average during extreme weather events and during above normal river runoff to stations on tidal rivers. Errors in time and height of tide are generally larger for those areas with weaker tides.

Tides can be predicted far in advance and with a high degree of accuracy. Tides are forced by the orbital relationships between the Earth, the moon and the Sun. These relationships are very well understood and the position of the celestial bodies can be forecast very accurately into the future.

The tides with the biggest difference between high and low water are called springs and those with the smallest are called neaps. Spring tides happen just after every full and new moon, when the sun, moon and earth are in line.