Underwater connecting apparatus and assemblies

1. An underwater connecting apparatus comprising:

a first flexible diaphragm defining a wall of a first chamber for receiving therein an electrical conductor and for containing an electrically insulating material around the electrical conductor; and

a second flexible diaphragm defining a wall of a second chamber,

wherein the first flexible diaphragm comprises an electrically conductive material and an outer surface exposed to pressure in the second chamber, and

wherein the second flexible diaphragm is exposed to pressure in a third chamber.

2. The apparatus as claimed in claim 1 , wherein the insulating material is a polymeric solid material.

3. The apparatus as claimed in claim 1 , wherein the first chamber is configured to receive an additional electrical conductor to provide an electrical connection with the electrical conductor in the first chamber.

4. The apparatus as claimed in claim 1 , wherein the first flexible diaphragm is configured to be earthed in use.

5. The apparatus as claimed in claim 1 , wherein the first flexible diaphragm is configured to engage a radially outwardly facing surface of a member extending axially into the first chamber.

6. The apparatus as claimed in claim 1 , wherein the first chamber extends in an axial direction and comprises a first axial end diameter at a first axial end that is smaller than a second axial end diameter at a second axial end.

7. The apparatus as claimed in claim 1 , wherein the second chamber wall comprises a second chamber perimeter with a non-circular profile when the second chamber is viewed in cross-section, the non-circular profile of the second chamber allowing a volume of the second chamber to change without changing a length of the second chamber perimeter.

8. The apparatus as claimed in claim 7 , wherein the second chamber perimeter comprises a wave shaped profile.

9. The apparatus as claimed in claim 1 , wherein the second flexible diaphragm comprises an annular seal member configured to engage in sealing manner with a radially inner member in order to seal between the second chamber and a region outside of the second chamber,

wherein the annular seal member comprises a first annularly and axially extending portion configured to engage the radially inner member and to extend axially along the radially inner member inwardly into the second chamber, the first portion being exposed to pressure in the second chamber, and

wherein a second annularly and axially extending portion is configured to engage the radially inner member and to extend axially along the radially inner member away from the second chamber, the second portion being exposed to pressure in the region outside the second chamber.

10. The apparatus as claimed in claim 1 , further comprising:

a third flexible diaphragm defining a wall of the third chamber,

wherein the third flexible diaphragm comprises an outer surface exposed to external ambient pressure.

11. The apparatus as claimed in claim 10 , wherein the third chamber wall comprises a third chamber perimeter with a non-circular profile when the third chamber is viewed in cross-section, the non-circular profile of the third chamber allowing a volume of the third chamber to change without changing a length of the third chamber perimeter.

12. The apparatus as claimed in claim 11 , wherein the third chamber perimeter comprises a wave shaped profile.

13. A cable termination assembly comprising:

an underwater connecting apparatus comprising:

a first flexible diaphragm defining a wall of a first chamber for receiving therein an electrical conductor and for containing an electrically insulating material around the electrical conductor; and

a second flexible diaphragm defining a wall of a second chamber,

wherein the first flexible diaphragm comprises an electrically conductive material and an outer surface exposed to pressure in the second chamber, and

wherein the second flexible diaphragm is exposed to pressure in a third chamber; and

a cable that extends into the first chamber.

14. An assembly as claimed in claim 13 , wherein the first flexible diaphragm engages a conductive screen of the cable.

15. An assembly as claimed in claim 13 , wherein the underwater connecting apparatus further comprises:

a third flexible diaphragm defining a wall of the third chamber,

wherein the third flexible diaphragm comprises an outer surface exposed to external ambient pressure.

16. An assembly as claimed in claim 15 , wherein the third chamber wall comprises a third chamber perimeter with a non-circular profile when the third chamber is viewed in cross-section, the non-circular profile of the third chamber allowing a volume of the third chamber to change without changing a length of the third chamber perimeter.