Repeater, feedthrough, and repeater manufacturing method

1. A repeater, comprising:

a pressure-tight casing configured to be arranged on a seabed or in a sea; and

a feedthrough having a plurality of leads including a central lead and a plurality of outer circumferential leads located on an outer circumferential side of the central lead, each of the plurality of leads being configured to connect a circuit housed in the pressure-tight casing with a cable outside the pressure-tight casing, wherein

the feedthrough has an intermediate lead located on an outer circumferential side of the central lead and on a center side of the outer circumferential leads, and

the intermediate lead is shorter in length than the central lead and longer in length than the outer circumferential leads.

2. The repeater according to claim 1 , wherein a measuring device is connected to one end of the cable.

3. The repeater according to claim 1 , wherein the plurality of outer circumferential leads are located on a concentric circle.

4. The repeater according to claim 1 , wherein

the feedthrough comprises a plurality of the intermediate leads, and

the plurality of intermediate leads are located on a concentric circle.

5. The repeater according to claim 1 , further comprising:

a main body section which is placed in the pressure-tight casing and through which the plurality of leads pass, wherein

the central lead is located at the center of the main body section.

6. The repeater according to claim 1 , wherein the feedthrough is an electric wire feedthrough configured to connect the plurality of leads to electric wire cables.

7. The repeater according to claim 1 , wherein the feedthrough is configured to connect the plurality of leads to optical fiber cables.

8. A feedthrough placed on a repeater which includes a pressure-tight casing configured to be arranged on a seabed or in a sea, the feedthrough comprising:

a plurality of lead sections including a central lead section and a plurality of outer circumferential lead sections located on an outer circumferential side of the central lead section, each of the plurality of lead sections configured to connect a circuit housed in the pressure-tight casing with a cable outside the pressure-tight casing, wherein

the feedthrough has an intermediate lead section located on an outer circumferential side of the central lead section and on a center side of the outer circumferential lead sections, and

the intermediate lead section is shorter in length than the central lead section and longer in length than the outer circumferential lead sections.

9. A repeater manufacturing method for manufacturing a repeater including a pressure-tight casing to be arranged on a seabed or in a sea and a feedthrough having a plurality of lead sections including a central lead section and a plurality of outer circumferential lead sections located on an outer circumferential side of the central lead section, each of the plurality of lead sections configured to connect a circuit housed in the pressure-tight casing with a cable outside the pressure-tight casing, the feedthrough has an intermediate lead section located on an outer circumferential side of the central lead section and on a center side of the outer circumferential lead sections, and

the intermediate lead section is shorter in length than the central lead section and longer in length than the outer circumferential lead sections, the repeater manufacturing method comprising:

connecting a first lead section of the plurality of lead sections with a first cable in one of an inner side and an outer side of the pressure-tight casing; and

thereafter, connecting a second lead section of the plurality of lead sections with a second cable in the one of the inner side and the outer side of the pressure-tight casing, the second lead section having a shorter length than the first lead section.