INWARD 2020 Scenario - Last Attack of the Arkansas

In a last minute change of plans, I've decided that my game for INWARD 2020 will be a semi-historical Dahlgren and Columbiad ACW riverine action between the CSS Arkansas and the USS Essex, which almost occurred on the 6th August 1862 (which seemed like too much of a coincidence to ignore): 

Lieutenant Stevens (was ordered) to take Arkansas down to Baton Rouge, Louisiana, where she would support an attack on the Union position there by a Confederate army force led by General Breckenridge. Stevens, under the orders of two superior officers, had to rush the ship down the river. 

The engines broke down several times between Vicksburg and Baton Rouge. Each time, the engineer was able to get them running again, but it was clear that they were unreliable. Nevertheless, the ship was able to get all the way to Baton Rouge, where she prepared for battle with a small Federal flotilla that included the USS Essex. 

On the morning of 6 August, Essex came in sight, and Arkansas moved into the stream to meet her. Just at this time, crank pins on both engines failed almost simultaneously, and Arkansas drifted helplessly to the shore.

Stevens prepared to abandon ship. He ordered the engines to be broken up, the guns to be loaded and excess shells spread around, and then the ship set afire. The crew then left. About this time, the ship broke free and began to drift down the river, and Stevens, the last man to leave, had to swim ashore. 

The burning vessel drifted down among the attacking Federal fleet, which watched from a respectful distance. At about noon, Arkansas blew up.

In my alternative scenario, the CSS Arkansas does manage to engage the USS Essex but must exit from the opposite end of the table in order to escape and win the game, preferably sinking the enemy ironclad in the process. The USS Essex must prevent the escape of the Arkansas by battering her into submission or by forcing her to ground in the shallows, where she can later be finished off at leisure by Union artillery onshore. 

CSS Arkansas

To reflect the poor mechanical state of the Arkansas, the Confederate player must roll a D6 in the Command Phase, with a score of 6 indicating that the crank pins have sheared and the ironclad is adrift. From this point onward, she will drift downstream at 2'' per turn and cannot steer. To even things up, the Union player must also roll a D6 at the same time each turn, with a 6 indicating a mechanical failure. 

Refer to Table 9 in the By Sea and River supplement with the following amendments:

Roll 2D6. 1-6 no problem / 7-8 = Gun problem / 9-10 = Boiler Trouble / 11-12 = Rudder Jammed.

The shallows on either side of the river channel are navigable but if entered a roll of 4, 5 or 6 will result in the vessel running aground on the sandy river bed, with a roll of 6 on a D6 in the Command Phase required to re-float. If the CSS Arkansas runs aground when her engines are out of action, she will be unable to re-float but may still engage in gunnery during the Action Phases of each turn.

USS Essex

The USS Essex will win a major victory if she manages to sink or force aground the CSS Arkansas. This will be reduced to a minor victory if she suffers Heavy or Severe Damage in the process. If the CSS Arkansas destroys the USS Essex or inflicts Serious Damage on her and then manages to escape, she will win a major victory. If she suffers Heavy or Severe Damage in the process but still manages to escape, this will be reduced to a minor victory. Any other result will be a draw.