@Luko p. My mistake a yacht can be anywhere :D

Hi @newtong, the Wallypower 118 have been spotted in Hvar, Croatia a few days ago (please see link http://www.yachtforums.com/threads/wally-118-spotted.16704/ provided by @davidships). Most likely it is the same yacht I spotted in Dubrovnik yesterday and today. I swam some 200 yards ahead of her bow, however could not see her name, probably is stenciled only at her stern.

Theres only one WallyPower and is in the united states now as "Galeocerdo"
http://www.shipspotting.com/gallery/photo.php?lid=2106892

Assuming that it is the same one (more than one of the Wally Power 118 design have apparently been built), then the name is probably WALLYPOWER, in one word. See the london-registered one at:
http://www.yachtforums.com/threads/wally-118-spotted.16704/

Thank you Dennis and Mark for identification.
The yacht has impressive engine power, however according to smoke she produced when starting the engines this morning - it seems some maintenance should be done.

Perhaps this one? http://www.superyachts.com/motor-yacht-4042/wally-power-118.htm