Steve, Upon re-reading the basic rules, there is no mention of the "surrender by striking her colors" rule as used in this on-line version of the game. Once a ship surrenders by striking her colors, all that the basic rules state is that, "Neither side is allowed to fire on a struck ship, although it can be boarded". The implication is that the ship remains on the board and DOES block broadsides, just as in the cases of the other types of surrenders. If there was a special rule regarding "surrender by striking her colors" it would have been detailed. Since it is not, then we must conclude that this on-line version of the game does differ from the boardgame in this instance.