Blisters on a Rudder
The Story
I had been aware of blisters in the rudder for some time but chose to ignore them until I damaged the leading edge of the rudder on a sand bank in the middle of the Thames Estuary (Middle Sand). At the same time I was aware of a leak around the rudder tube that required the rudder to be dropped for investigations.
After lift out a hole was dug and the rudder dropped.
The rudder was damaged at leading edge corner and water was dripping out.
With the rudder upside down water also came out from around the top edge.
Since repairs were obviously going to be required to the bottom of the rudder I decided to investigate the some blisters. The blisters were not what I expected as osmotic blisters seeming to be more like the intact gel coat being forced away from the core over an area of about 12 to 1.5" diameter. This is not obvious in the pictures. After opening up some of the blisters they all were wet inside.
The hole along the bottom of the rudder was opened up and the rudder set up in a shed to allow it to dry.