Abstract: The object of this invention is to provide a prefabricated boat consisting of a reinforced plastic boat body (1), and a rubber tube (2) detachably attached along each side of the body (1) to give buoyancy to the body (1). The sides of the boat body (1) each have a longitudinal guide groove (4) designed such that the tubes (2) are closely attached to the body (1) with enlarged contact surfaces between the tubes (2) and the body (1). Upper and lower brackets (6), each having a fitting groove (5), are formed along the upper and lower edges of each guide groove (4). Each tube (2) has two slidable fittings (7) engaging with the fitting grooves (5) of the two brackets (6). This boat thus minimizes hydraulic impact energy applied to the tubes (2) during a voyage, thus improving its sailing stability and cruising power as well as increasing its mileage.

Abstract: The object of this invention is to provide a prefabricated boat consisting of a reinforced plastic boat body (1), and a rubber tube (2) detachably attached along each side of the body (1) to give buoyancy to the body (1). The sides of the boat body (1) each have a longitudinal guide groove (4) designed such that the tubes (2) are closely attached to the body (1) with enlarged contact surfaces between the tubes (2) and the body (1). Upper and lower brackets (6), each having a fitting groove (5), are formed along the upper and lower edges of each guide groove (4). Each tube (2) has two slidable fittings (7) engaging with the fitting grooves (5) of the two brackets (6). This boat thus minimizes hydraulic impact energy applied to the tubes (2) during a voyage, thus improving its sailing stability and cruising power as well as increasing its mileage.

Abstract: An apparatus for removing unnecessary data in communication networks and used in a television transmitting and receiving devices of a cable television system and the like is disclosed. In a television receiving device capable of carrying out data communications, if an unnecessary data such as an address change command is contained in the data stream transmitted from the transmitting device to the receiving device, the unnecessary data is removed in advance. That is, in the present invention, if an unnecessary data is contained in a command, then a CRC error is forcibly generated, so that the receiving device can ignore a data stream containing the unnecessary data, thereby removing unnecessary data. In this manner, the damages to the software or hardware of the receiving device can be prevented.