53. Where, for the purposes of this Ordinance or any rules made thereunder, any document is to be served on any person, that document may be served- (a) in any case, by delivering a copy thereof personally to the person to be served; or (b) if the document is to be served on the skipper or on a person on board a fishing vessel, by leaving the same for him on board that vessel with the skipper or the person who is, or appears to be, in command or charge of the vessel for the time being; or (c) by affixing a copy of the document to any conspicuous part of his residence; or (d) sending it by registered post acknowledgement due addressed to his last known place of abode.