Where was the copper sheathing fitted on the HMS alarm and why?

Answer 1

It was fitted on the hull. This is because copper is an antifouling material so marine organisms have great difficulty attaching. Without marine organisms (fouling) there is less resistance and the boat can go much faster.

Answer 2

The copper sheathing was fitted on the hull of HMS Alarm below the waterline to protect the wooden hull from damage caused by marine organisms such as teredo worms and barnacles. The copper sheathing was an anti-fouling measure that helped to prevent the growth of these organisms, thus reducing drag and improving the ship's speed and maneuverability.