Ministry of Agriculture & Land

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As Jamaica continues to enjoy an increase in the use of its ports by cruise ships and trade vessels, the Hydrography Unit in the National Land Agency (NLA) is playing a key role in ensuring that these ships can safely navigate the island's costal waters.

Manager of Topographic and Hydrographic Surveys at the NLA, Calvin Thompson, tells JIS News that the agency works closely with the Port Authority of Jamaica to maintain adequate hydrographic coverage of the island's major ports and harbours, to facilitate the safe movement of ships.

He points out that most of the world's goods are transported by ships and "any state, coastal or otherwise, that relies on shipping for trade and industry, must place great importance on hydrographic products and services... otherwise our major operations that have to do with tourism, transshipment, export, imports could be impacted adversely".

He notes that in addition to a vibrant and expanding transshipment industry, Jamaica's territorial waters and (exclusive) economic zone spans important shipping lanes and it is "extremely important that we survey these waters to ensure that we identify where there are hazards and where it is clear for ships to navigate."

Ensuring the safety of the nation's costal waters is also part of the Safety of Life At Sea (SOLAS) Convention, which Mr. Thompson explains, "seeks to govern anything to do with the movement of vessels on water and make specific provisions for countries to provide hydrographic products and services to facilitate safety of navigation."

"Shipping interests pay keen attention to these provisions and any state that contravenes or fails to comply with the requirements run the risk of being blacklisted or avoided by these shipping interest groups or increased liability in the event of maritime accidents. This action could have devastating effect on the state's industries that rely on shipping and hence, its economy," he points out.

Explaining the concept of hydrography, Mr. Thompson tells JIS News that the process involves "the taking of measurements on a water body in order to establish among other things, the depth of the water, the location of any obstruction, as well as any significant features on the seabed and object on the surface that could act as an (hindrance) to navigation".

The measurement collected is used to create charts to outline, among other things, the depth and details of the water at specific locations.

However, because the Hydrography Unit does not have the capacity to create these charts, what it produces are hydrographic field sheets or smooth sheets, which show to a very high density, the depth of the water in the areas that have been surveyed. These sheets are then sent to the United Kingdom Hydrographic Office where the charts are produced and published.

These charts, Mr. Thompson says, are very vital because they help a ship's captain to determine whether or not it is safe to take his ship into a particular harbour or port. "When you are on the surface of the water sailing, it is impossible to see the hazard underneath and by using these charts, he is able to decide whether he can sail into any port, do his business and sail back out safely."

The Hydrographic Manager explains that the unit also provides data in the event that a captain wants to enter a port but feels that the information available is outdated or otherwise unreliable.

"The Port Authority of Jamaica would then invite us to supply them with more updated information and the agency would send out the hydrographic team to collect the data for the particular area of interest and supply the Port Authority with a smooth sheet. The Authority would then communicate the updated information to the mariner and, if necessary, forward the smooth sheet to the charting agency for updating of the chart," he informs.

Outlining the method used to collect hydrographic data, Mr. Thompson says that "the instrument most commonly used for depth measurement is known as an echo sounder. This instrument transmits electromagnetic pulses or high frequency sounds that travel through the water and are reflected from the seabed. The return travel time for the pulse is used to calculate the depth and this is recorded on a graphical printout. The measurement is done on a continuous basis while the boat is in motion".

"Simultaneously with the measurement of the depth, the position of the boat can now be fixed by .a Global Positioning System (GPS) receiver. The GPS uses radio signals received from special satellites to establish its position. This determination can also be done on a continuous basis. Hence, both depth and position measurements can be taken accurately and easily," he says.

Mr. Thompson notes that while the NLA has surveyed all of the country's major ports and harbours including Port Esquvel and Port Morant and the Kingston, Ocho Rios, Port Antonio, and Montego Bay harbours, there is great difficulty in surveying offshore areas.

"Jamaica has a number of cays and islands off its mainland. Our (exclusive) economic zone extends well beyond where the cays are and our difficulty is that, based on present capabilities, we are able to survey mostly our inshore areas but the offshore areas are not being surveyed, at least not by modern methods," he says.

He further points to the needs for funds to purchase the required technology and equipment to execute these surveys, but noted that the agency was committed to the process and will do more to meet Jamaica's hydrographic obligations under the SOLAS Convention.

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