There might have been records on board the Titanic if there were stowaways, but the ship's log went down with the ship - so no, no evidence exists today of any stowaways - not to say there wasn't any, just that there's no evidence of any.
Occasionally, you hear rumours and some innuendo that's been passed down, but as Kyrila pointed out, there is no extant documentary evidence that there were any stowaways on the ship. If there were, it's dead cinch that not one made it off alive. Every one of the survivors was taken aboard the Carpathia and to the last man, woman, and child, each one was a ticketed passenger.
It may be of some interest that, if I recall correctly, it was not until Olympic's third voyage that any stowaways were caught onboard. From what I remember, stowaways were generally discovered every few voyages. That being the case, judging from the frequency of stowaways onboard the Olympic during this period I would venture the opinion that it would be statistically less likely for a stowaway to have been onboard (or at least discovered onboard).
For my own money, I don't think it would take long for a stowaway to be discovered. All else aside, sooner or later, they would have to come out of their hiding places to get something to eat. I distantly recall that quite a few were caught that way on a number of liners. Further, with paid for berths accounted for, I don't think it would have taken long for an eagle eyed steward to notice some space that was being used that should not have been occupied.
There are reports that the recently sunk Costa Concordia may have had one or more stowaways on board. Have there been any similar thoughts regarding Titanic? It would seem to have been easier in Titanic's era than for modern cruise ships.
>>Have there been any similar thoughts regarding Titanic? <<
Yes. None substantiated.
>>It would seem to have been easier in Titanic's era than for modern cruise ships.<<
Getting on wasn't that much of a problem. Avoiding detection, that was the problem. Not as many got away with it as you might think. Sooner or later, one had to come out to eat and stewards were remarkably adept at identifying people who didn't belong there.
Well... I don't want to sound like a bigger authority on this issue than those who have been members of Encyclopedia Titanica for far longer than me, but I recently found a piece of information showing that there were stowaways on the Titanic.
My source is a letter from fireman George Kemish to Walter Lord, of which there is a transcript on Charles Pellegrino's website. There are a few passages in said letter showing that there were indeed stowaways on the Titanic.
"There were also some stowaways that went down with the ship. Stowing away in those days was quite easy; [as] it was very easy to walk ashore in New York. Restrictions then were not nearly so strict as now."
"“Jumping the freight" was another simple matter. No one knew who the stowaways were. Apparently they had no relations or friends. That type is to be seen in most big ports. Never missing, because they are never known — just world wanderers. They were always welcomed by us because they would keep our quarters clean."
Also, according to said website, George Kemish once lamented to Walter Lord about the stowaways, "They were young, penniless world wanderers. Adventurers. We had always welcomed them, and they us, for keeping the place clean and keeping their secret. Kept their secret too well, I guess. Their skeletons are still down there, I suppose, near [Mr. William Carter’s Renault town]car in the forward hold. No one will ever know who they were."
For those of you interested in seeing the statements as they are originally presented, go to the following webpage:
Well, it seems I should have thought for a little bit longer before quoting that source, considering Pellegrino seems to be less reliable of an author than I imagined - at least, that's what I read in many posts.
But if the letter of George Kemish on his website is indeed a true transcript, and George Kemish really lamented that bit to Walter Lord, then the bits about the stowaways are true by extension. Of course, there's always the possibility that the letter Pellegrino quotes never existed... but I think that is a bit of a stretch.
Well, as has been said earlier, if there were any stowaways then they didn't make it off the ship alive, that much we can be sure of. IMO their best chance would have been sneaking on board with the cargo rather than trying to fake it up the gangways or similar.
Also we must remember the possibility that there were stowaways on board who might have disembarked in Cherbourg or Queenstown, just after a free ride across the Channel.