[A_Brandybuck]

I agree with narfforc. Círdan is often seen as a simple boat-builder and Guard of the Havens. But one time I analysed Círdan's behaviour in the First Age and came to the conclusion, that all his actions he took were in a very helping or diplomatic way.

He is a very helpingful character and never took some actions for himself or for his reputation. Also he don't care of the intern quarrels of the Elves of Beleriand. He seems to be the 'good soul'.
Under these points, we don't have to wonder, that Círdan gave the Ring away. He saw, that the Ring is elsewhere better to use. In his function of the Guardian of the Haven, there was little use for the Ring. So not thinking only of himself, he gave it to Gandalf, because he saw, that the Ring would be used in a good way by Gandalf.

In my opinion, Gandalf was the right choice under the Istari (not considering the fact, that I know, that all others have failed) to get the Ring. His nature was 'prepared for the Ring', because the Ring enhanced his good abilities to bring delight and courage to the hearts of the free peoples.
And I am sure, that Círdan knows of the special abilities of the Ring and that these abilities goes well with the abilities of Gandalf.