NAUTICAL SERVICES AND BOATS IN MALLORCA – SEYKA YACHTS. At Seyka Yachts we offer high quality services in the maintenance and repair of your boat in the Balearic Islands, Barcelona, Valencia and Denia. Cleaning services, visit your boat at the mooring every x days, check ropes and mooring lines that are correct, prepare for adverse weather conditions, have your boat ready for when you are going to use it, transfer in navigations , etc.