I think I lay thinking about bulkhead #3 half the night. By 5 am it was getting really bad, so I got up! I looked at the drawings again and then it struck me, I was using 1x2's as stringers which are 3/4" x 1 1/2" true not the 1 3/4" that Wharram has on the drawings. The ruler lying on the bulkhead shows the 1/4" difference. I went out to the shed and discovered that the problem was too fold; one the bulkhead was not sitting plumb but had wave in it and two the notch on bulkhead 3 was 1/4" too low. Suddenly the 1 inch problem was fixed by removing the wave in the bulkhead (from compression forces pulling the sides together and in line) and recutting the notch so the bulkhead could sit higher. PROBLEM FIXED! Now I could move ahead to finishing wiring the bulkheads in and cutting bunk bearers and cabin top bearers.