Followup ROV tests

Several modification have been made to the ROV to improve performance:
- The large buoyancy tanks have been removed and replaced with smaller strips of foam
- Some holes were cut in the bottom grate to improve water flow.
- Sinkers have been fitted to fine-tune the buoyancy
- 12V 3A SLA battery was fitted
The results were the ROV is now considerably faster - 14cm/second with a turn speed of 45 degrees per second.