I've read about others that have added an aeration tube to their BlackHawk. From what I've read, the air sucked in by the props, reduces the torque load on the drive when the props are submerged and this can result in easier shifting and reduce idle speed due to increased prop slip at idle. It can also reduce planing time by allowing the motor to build rpm faster.
I don't have the latter problem, but shifting is a PITA. I wouldn't mind a reduced idle speed, but the shifting issue is the main reason I'm going to try an aeration tube.
I bought a length of 2"OD aluminum tube and marked the cover plate where I wanted to install it and cut the hole.
Aeration marking.jpg
Then I cut through the cavitation plate.
Aeration cav.jpg Aeration cav plate.jpg
...and then through the anode that mounts to the underside of the cavitation plate.
Aeration anode.jpg
Here's a look of where the air will enter relative to the props. In the 1st pick you see the blade of the front prop through the holes. In the 2nd pic, I dropped the tube onto the prop to get a clear image of where the air will hit the props.
Aeration prop view.jpg Aeration tube.jpg
I briefly debated on adding a support bracket, but it looks ugly as chit and I determined it's not need structurally, so I'm not going to bother. (I just have to keep people from using the tube as a grab handle when climbing up the drive).
Aeration supports.jpg
Here the cover is prepped for welding the tube. The tube will be welded to the top cover only and it will protrude enough to fit to the bottom of the cavitation plate hole.
Aeration cover prep.jpg Aeration cover prep2.jpg
I'll post a pic when the tube is welded in place, and if I ever get the boat on the water again, I'll cut the tube to the proper height...and update on the results.