The Oasis of the Seas completed its sea trials off the coast of Finland this weekend and had only one "nasty surprise," as Royal Caribbean's chairman Richard Fain put it.

The sea trials included a test of the aerostat -- a helium-filled, blimp-like craft -- which was tethered to the back of the ship by a stainless steel cable.

If successful, the blimp ride could become an onboard activity for passengers during Oasis cruises.

Its maker, Lindstrand Technologies Ltd., was conducting an unmanned test flight of the aerostat when a failure occurred and the aerostat separated from the ship and drifted away over open water. No one was injured during the incident, and no damage to the ship occurred.

"Most of the trials were a terrific success. The ship performed her various tests very well and everyone is very excited," said Fain in his online blog. "BUT, we had one nasty surprise early this morning. ... Something happened and the balloon broke free. It ended up in the water and we are now taking steps to recover it and determine what happened. This is precisely why we do such tests (and why I don't take credit until we know whether or not they are successful)."

Royal Caribbean said it is working with Lindstrand to evaluate the cause of the incident.

To read more on Fain's experiences onboard the Oasis during its sea trials, go to www.oasisoftheseas.com/chairmans-blog.