The USN wanted the capsule so it could act as a life boat (LOL!) if the crew had to eject over water, so that meant that the capsule also had to float. As I say, the USN did everything they could to make sure the F-111 failed the trials.
Once the USN brass knew they weren't going to be saddled with 'The Pig', and were going to get the F-14, they went back to conventional tandem seating, standard ejection seats and external stores.
Story goes that an F-111 crew had to eject. When the rescue crews arrived at the capsule they had to restrain both parties as they almost came to blows with each other arguing over what time to put on the travel voucher. One crew member was adamant that the time should be when the capsule landed, the other maintained it should have been the time the stricken aircraft hit the ground.
BTW the F-111 egress capsule design was originally going to be used in the space shuttle but it was nixed as too expensive. Most egress types I knew say it had a good chance of working in the Challenger’s case.