How can I clear a blockage to the black water tank in my 1160 / 1260?

Both the forward and aft black water tanks (toilet waste) on the the 1160/1190/1260 3 cabin boats have the same configuration. 

Per the below aft tank layout, the deck pump-out fitting is aligned over the through hull outlet. This allows a fine pressure hose, batten, or wire to be pushed down through the deck fitting, down into the base of the tank as an option to dislodge unwanted debris/blockages, right over the tank outlet. 

Also note that the toilet to tank inlet has to pass through a riser. This ensures that there is no head of pressure on the toilet during normal operation (back filling). 

Final resorts for tank blockage involve a quick swim, the aforementioned batten or wire, and lightning quick swimming abilitites...