Well, I just Googled, & I found this here
"Parliament, or parliamentary, heel, a makeshift method of cleaning or repairing the sides of a British naval ship of the era of sail when there was neither time nor opportunity to careen or dock her. She was heeled over by running the guns from one side of the ship over to the other side. Only the upper strakes could be cleaned since the maximum angle of heel with the ship still afloat was limited by the level of the lower gunports. According to an old belief, the name derived from the contempt in which parliamentary rule was held in the English Navy, implying that a half-done job was good enough to satisfy a parliamentarian. However, the more likely derivation is from the period of its introduction, the term coming into the British Navy during the First Anglo-Dutch War (1652–4) when England was governed by Cromwell's Parliament and when this process was much used. It did not spread into general use beyond the English Navy.
When, in 1782, HMS Royal George capsized and sank at Spithead with a great loss of life, she was undergoing a Parliament heel to carry out underwater repairs."