I agree, they wouldn't have made it; the Germans never had a decent Navy ( apart from early surprise attacks on trading ships by 'pocket battleships' such as Graf Spee ) and would have been slaughtered by aircraft & home fleet.
I happened to work on a similar barge ( in Burgundy, 1994 ) and any stretch of open water was scary ! - I'm a sailor & yachtmaster offshore ( also been involved with Harriers & Hawks a bit ) with 24 crossings under my belt, and I know a barge crew who did cross the Channel; they kept the 45 degree scrape marks from the clock on the bulkhead as a momento of the the day they thought death was within 5 minutes !
As for Bader, we could do perfectly well without his type...I presume you've seen the recent programme which concluded he was shot down, and indeed played up to the Luftwaffe officers, asking if a proficient ace had got him, then later claimed he was in a collision.