Wedging the space between the ribs to stop the plank from splitting along its length

First job is to cut a number of wedges to see which size fits between the back of the rib and the face of the plank 

The space under the rib where the nail goes through is where the wedge as to go in order for the plank not to spilt  

Here is a wedge in place ready for the nail to go through 

Full wedges that need to be cut down to length and thickness 

All the wedges in position and ready for the bilge stringer to go into position 

The bilge stringer now nailed down in position