I had new cushions made for my 23.5 out of a fabric made for outdoor furniture with extra batting so the berths are more comfortable to sleep on. It cost me about $1800 but everything is new. A local upholsterer used the old cushions as patterns, suggested fabric choices, talked me out of my cheap idea of making covers to fit over my existing cushions, and it turned out to be a really a great upgrade. The fabric does not get hot and sticky in the sun like the original material and the musty smell is gone. I keep damp rid in my boat to keep the moisture under control and stop mold and mildew from growing. I tried everything on those old cushions too. There is nothing worse than that musty old boat smell. Spring for new cushions and your boat will smell like new.