A Logbook was originally a book for recording readings from the log, and is used to determine the distance a ship traveled within a certain amount of time. The readings of the log have been recorded in equal times to give the distance traveled with respect to a given start position.

Today's ship's log has grown to contain other types of information, and is a record of data relating to a ship or submarine, such as weather conditions, crew complement or what ports were docked at and when. It is essential to traditional navigation, and must be filled in at least daily.

Clipper   Log Book contain the fishing data as a catch position, type of catch, tons, wells, temperature etc.

A shackle is a U-shaped piece of metal secured with a pin or bolt across the opening, or a hinged metal loop secured with a quick-release locking pin mechanism. They are used as a connecting link in all manner of rigging systems, from boats and ships to industrial crane rigging. A carabiner is a variety of shackle used in mountaineering.

In fishing net terminology "purse" is used as a verb and adjective but seldom as a noun. Literally to purse is to close an opening by pulling a line which has been threaded through rings attached to the edges of the opening.

In roundhaul nets there are several different kinds of pursing devices, the most important being the closing of the bottom of a net after it has been circled about a school of fish. Floats along the headrope of a net are bunched by hauling a cork purse line through rings on the corkline. At either of the lower corners of a purse seine the leadline is brought to the surface by means of a short purse line through rings on the end of the net (breast line).

The central portion of a leadline is brought to the surface and the wall of netting closed off by pulling a vertical line through rings on the webbing. This is more graphically called a "zipper." Closing and opening of the pouch of a dipnet (brail) is accomplished by a miniature purse line (tripline) through rings.

Purse-seine nets are set vertically in the water, with floats attached to the upper edge, while along the lower edge is a chain, for weight, and a series of rings, through which the pursing cable passes. Purse-seine nets can be as long as 1.5 km and more than 150 m deep. On sighting a school of tuna, a large skiff with the end of the net attached is released from the stern of the fishing vessel. The vessel encircles the school with the net. The cable is hauled aboard the vessel, causing the bottom of the net to close, and the fish are trapped inside the pursed net. Most of the net is then pulled aboard the vessel, confining the fish in a “sack,” from which they are transferred to the deck of the vessel. Tuna purse-seiners vary in length between about 30 to 115 meters, and can pack on board up to 4 000 tonnes of frozen fish. However, most high-seas tuna seiners average about 70 to 80 meters in length and can carry about 1 000 to 1 500 tonnes of frozen tuna. Such vessels can fish throughout the oceans of the world, and make trips that last up to several months before returning to port. Many carry helicopters to improve their efficiency in finding and catching fish.

Purse seiners target mostly yellowfin tuna and skipjack, and on a world scale account for roughly 60% of all the tuna landed. In recent years the purse-seine catch of bigeye tuna has been increasing rapidly, mostly due to the increased use of FADs.

Sometimes, a school of tuna not associated with dolphins or a floating object can be detected from signs on the surface of the water. Schools moving energetically close to the surface disturb the water, which sometimes appears to be boiling or affected by a breeze. Frequently, the presence of birds is a further clue to the presence of a “boiler ” or “breezer.” In other cases, a school swimming close to the surface is detected as a “black spot” from the vessel or helicopter, or the tuna are seen jumping. Setting on all types of unassociated schools is known as school fishing.

Tuna are attracted to floating objects such as logs and debris. These floating objects are referred to collectively as logs. Sometimes, artificial fish-aggregating devices (FADs) are set in the ocean to attract tuna. The tuna that collect around the logs are then caught by means of purse seines.

The term skiff is used, and has been used, to refer to many various types of seemingly unrelated small boats. In the tuna fishing is used to hold one of the ends of the net, in order for the boat to deploy it, and it´s powered by a very powerful motor to tow both the seiner and the net.

  PELAGIC:

Living in open oceans or seas, not near land.

    PURSE SEINING is a method used to catch TUNA.
A seine or net is drawn out from the fishing boat and around the school of TUNA.
Weights carry one edge of the seine deep into the water.
When the fish are surrounded, the bottom of the seine is drawn together or pursed, so that the fish are trapped and hauled aboard the boat.
This method accounts for about 80 percent of the commercial catch of Light Meat TUNA