The new Sirena 58 is built for liveaboard comfort with lots of space inside and out. It also is built for long-range cruising. Indeed, German Frers, the famed naval architect who designed it, says it’s a mini explorer yacht made for cruising “all corners of the world.” The new cruiser, built by Sirena Yachts in Turkey, has a Frers-designed hull that’s smooth and efficient at displacement and planing speeds. With two standard 650-hp Cat diesels, the Sirena 58 tops out at 26.5 knots; with optional 850-hp Cats, it reaches 30 knots. Dial back to 10 knots, and the Sirena 58…