Puretic power block

The Puretic power block is a special kind of mechanised winch used to haul nets on fishing vessels. The power block is a large powered aluminium pulley with a hard rubber-coated sheave. While many men were needed for the back-breaking work of hauling a purse seine manually, the same work could be done by fewer men with a power block.[1]

The Puretic power block revolutionized the technology of hauling fishing nets, particularly purse seine nets. According to the Food and Agriculture Organization of the United Nations (FAO), "no single invention has contributed more to the success of purse seine net hauling" than the power block, which was "the linch-pin in the mechanization of purse seining".[2][3]

Puretic Block
Puretic power block
Albatun Dod
Large blue water tuna purse seiner. A Puretic power block can be seen at the top of the boom at the stern.


The power block was invented by a Croatian fisherman, Mario Puratić, and patented in 1953. In English, Puratić is usually spelt Puretic, sometimes Puretich.

While he was working as a tuna and sardine fisherman from San Pedro, California, Puratić started thinking about the difficulty of hauling seine nets. The original power block he designed was essentially a simple winch which used a V-shaped roller coated with hard rubber. It was suspended from a davit, and powered from the warp end of the winch by a looping rope. In 1954, the power block was trialled by American purse seiners in the Pacific. They have evolved since then, and nowadays power blocks are powered by hydraulic pumps. Their speed, torque and direction can be remotely controlled from the bridge during operations. As a result, retrieving the net is safer and requires less manual work.[2][4]

Other important innovations of the same period were the development of synthetic fishing nets and sonar detection devices. The combination of the automated power block hauling synthetic nets with sonar sensing revolutionised the industry.[1]

The use of power blocks was found to have further advantages. It is possible to fish in rougher weather with the power block, because the steady force exerted by the net stabilizes the vessel. When deployments are made which miss the schooling fish, the net can be rapidly retrieved and redeployed on the same school. The power block also makes it easy to get nets aboard in emergencies, such as a sudden shift in tides or winds, or shark attacks on the catch and net.[1]

On the other hand, the increase in the effectiveness of purse seine fishing led to herring schools choosing to school deeper in the water. Nets that could operate in deeper water needed to be bigger and heavier. That in turn meant bigger vessels, which pushed the smaller herring vessels out of business.[1]


Salmon seiner drumming in the net
Salmon seiner with power block 1967
Hauling net with power block on salmon purse seiner
Closeup of the power block

Seine fishing industries rapidly recognized the value of the power block, and by 1960, most northern seine vessels were using the power block. Nowadays power blocks come with dozens of configurations and sizes. They are installed on over twenty thousand fishing vessels across the major purse seining fisheries around the world.[5] These fisheries haul huge schools of tuna, salmon, herring, sardines, anchovies and menhaden from the sea,[1] accounting for a large part the world total fish catch.[6]

Between 1969 and 1979, the Puretic power block was pictured on the reverse side of Canadian five dollar banknote issues.[7] In 1975 Mario Puratić was given the National Inventor of the Year Award by the Intellectual Property Owners Education Foundation for his invention of the power block.[8]


  1. ^ a b c d e Schmidt PG (1959) "The Puretic power block and its effect on modern purse seining". In Modern Fishing Gear Of The World 1, pp. 400–414. Editor Hilmar Kristjohsson, FAO, Rome.
  2. ^ a b FAO: Fishing Equipment: Power block Rome. Retrieved 28 May 2009.
  3. ^ The Power Block FishByes, December 1995.
  4. ^ Bardarson, HR (1971) "Deck Equipment for Purse Seining". In Modern Fishing Gear Of The World 3, pp. 283–287, Editor Hilmar Kristjohsson, FAO, Rome. Download PDF (56MB)
  5. ^ MARCO, the Puretic power block, and Purse Seining. Fishing News International Archived 2009-04-29 at the Wayback Machine Download PDF (19MB)
  6. ^ FAO: Fisheries and Aquaculture Department Rome.
  7. ^ Banknote > Canada > 5 Dollars > 1969-1975 Issue colnect.com, retrieved 17 October 2016.
  8. ^ Inventor of the Year Award: Past Awards Archived 2011-10-06 at the Wayback Machine Intellectual Property Owners Education Foundation.
Croatian Americans

Croatian Americans or Croat Americans (Croatian: Američki Hrvati or Hrvati u Americi) are Americans who have full or partial Croatian ancestry. In 2012, there were 414,714 American citizens of Croat or Croatian descent living in the United States as per revised 2010 United States Census. The figure includes all people affiliated with United States who claim Croatian ancestry, both those born in the country and naturalized citizens, as well as those with dual citizenship who affiliate themselves with both countries or cultures.

Croatian Americans are closely related to other European American ethnic groups, especially Slavic Americans and are predominantly of Roman Catholic faith. Regions with significant Croatian American population include metropolitan areas of Chicago, Cleveland, New York City, Southern California and especially Pittsburgh, the seat of Croatian Fraternal Union, fraternal benefit society of the Croatian diaspora. Croatia's State Office for the Croats Abroad estimated that there are up to 1.2 million Croats and their descendants living in the United States.

Fishing vessel

A fishing vessel is a boat or ship used to catch fish in the sea, or on a lake or river. Many different kinds of vessels are used in commercial, artisanal and recreational fishing.

According to the FAO, there are currently (2004) four million commercial fishing vessels. About 1.3 million of these are decked vessels with enclosed areas. Nearly all of these decked vessels are mechanised, and 40,000 of them are over 100 tons. At the other extreme, two-thirds (1.8 million) of the undecked boats are traditional craft of various types, powered only by sail and oars. These boats are used by artisan fishers.

It is difficult to estimate the number of recreational fishing boats. They range in size from small dinghies to large charter cruisers, and unlike commercial fishing vessels, are often not dedicated just to fishing.

Prior to the 1950s there was little standardisation of fishing boats. Designs could vary between ports and boatyards. Traditionally boats were built of wood, but wood is not often used now because it has higher maintenance costs and lower durability. Fibreglass is used increasingly in smaller fishing vessels up to 25 metres (100 tons), while steel is usually used on vessels above 25 metres.

List of Croatian Americans

This is a list of notable Croatian Americans, including both original immigrants who obtained American citizenship and their American descendants.

To be included in this list, the person must have a Wikipedia article showing they are Croatian American or must have references showing they are Croatian American and are notable.

List of Croatian inventions and discoveries

Croatian inventions and discoveries are objects, processes or techniques invented or discovered, by people from Croatia.

List of inventions named after people

This is a list of inventions followed by name of the inventor (or whomever else it is named after). For other lists of eponyms (names derived from people) see Lists of etymologies.

Mario Puratić

Mario Puratić (1917 - 1993) (usually spelled Puretic, and sometimes Puretich, in English) is a Croatian-born American inventor who made major advances in fishing technology, such as the Puretic power block.Puratić was born in 1917 in the town of Sumartin on the island of Brač in a Croatian family of farmers and fishermen.

In 1938 he emigrated to the United States, worked at steel works and later in the harbour of Brooklyn.

Looking for the open sea after World War II he moved to California, to San Pedro, where many people from Brač had moved to. He hired there on tuna fisher boats and trawlers. A good catch of fish, meant that many men were necessary to pull the net onboard.

Within a few months, during 1953 in San Pedro he invented the Puretic power block. A job which once needed 8 to 10 people could now equally quickly be done with only 5 or 6 people, but still no one was interested in the product.

In 1955 the company Marco from Seattle, specialized in sea building and design, recognized the potential of his invention and its engineers produced a product for practical use called the Power Block. It has a form of evening pulley with aluminium skeleton and the central rotating element, often wrapped in hard rubber, which can work. Quality of the product was very quickly recognized and up until 1960, most fishing boats in the northern seine fleet had installed the power block. It made possible the renaissance of the moribund United States distant water tuna fleet, an event that put the United States into the forefront of the fishing world and has kept it there, helped by the adoption of synthetic fibers for netting.

Due to his invention, Peru increased its fishing pelagic fish by 300 percent.

The puretic power block revolutionized the fishing industry in such a way that FAO stated that no single invention has contributed more to the success of purse seine net hauling than extensive line of Power Blocks.

In 1972 Canada issued a five dollar bill with a salmon seiner on the reverse.

In 1975, Mario Puratić was proclaimed the inventor of the year in the United States and also one among America's most famous 100 inventors of the 20th century.

Seine fishing

Seine ( SAYN) fishing (or seine-haul fishing) is a method of fishing that employs a fishing net called a seine, that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats. Seine nets can be deployed from the shore as a beach seine, or from a boat.

Boats deploying seine nets are known as seiners. Two main types of seine net are deployed from seiners: purse seines and Danish seines.

Fisheries and fishing topic areas

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