You can now see a number of copper spikes standing upright on the seabed. These are the remains of the copper bolts used to fasten the timbers of the hull. Before 1780 ships were fastened using iron bolts. After the introduction of copper sheathing below the waterline it was soon discovered that the iron bolts corroded rapidly. The solution to this problem was to use copper fastenings below the waterline. The sharp points seen on these copper bolts are caused by erosion of the exposed bolts on the seabed. Take care to avoid the sharp points!
The timbers you see here are the partly buried hull timbers. These consist of the inner planking, frames and outer planking. You are at the level of the orlop deck, where cables and sails were stored, below the water line of the vessel.