As I posted elsewhere...I agree with the sentiments that marine composites have a harder life than a composite aeroplane.
The fundamental problem a lot of people have,is understanding that Laminates do NOT need to be replaced as complete panels.
a "patch" can be laid-up in situ, or a part-panel "let in" to replace a damaged area and the finished repair has the same integrity as a piece that was all laid-up at the same time.
Anyone dismissing the danger of an "at sea" failure, may like to cast their mind back to Tony Bullimore's adventure, where the (metal) keel snapped off his (composite) yacht.
I'd venture that the loads imposed by a mast ~80 feet high, pulling a large yacht over to 45* + , with several tons of heavy keel counterbalancing it, in a sea of waves higher than a house, slamming the lot continuously.....is a greater loading than that on a pair of wings lifting a fuselage into the air.
Just gut-feeling, you understand....but try walking on the seafront on a stormy day and tell which hits the hardest.....gusts or spray?