Length is a big factor in the suitability of multihulls for offshore
sailing. The righting moment (the abilty to resist overturning) can be expressed in pounds of force. 35,000 lbs is considered safe for offshore
sailing. A cat is generally approaching this number at 30 feet. Another thing to consider is payload capacity. Many consider multihulls under 30 feet to lack the payload capacity for serious cruising.
It can be done but you have to be ruthless in keeping the weight down. It may be okay to overload a small multihull
in sheltered waters but offshore you will have a slow, cranky boat that will slam it's underbody. It may lack the reserve bouyancy to rise to oncoming waves and to avoid stuffing a bow in the trough coming down a large wave. I am sure the Prout would be fine for the Baltic
or the Med. You could even take it offshore but your margin for error is small. Keep it light.
See if you can find a copy of The Cruising Multiull by Chris White.