Apparently it was planned that Hitler would receive the British surrender on board the Aviso Grille and then proceed up the Thames on her pinnace the Grillet. As he was a poor sailor he might have been some what green. The closest the Aviso Grille actually got was laying some mines in the Thames estuary.
And so I'm surprised that he didn't plan hist triumph on a pocket battleship or a heavy cruiser. The Deutschland might have been appropriate ( and a lot more stable) but perhaps he never really believed in Sealion?.