Lifetime is running out for a large number of fibreglass boats produced about 50 years ago. Many shipyards where they have been produced do no longer exist and last users frequently do not have the budget to pay expensive disposal of their boats. After having been chopped and shredded the only further (but still expensive) use of the fibreglass seems to be as a waste component in concrete or asphalt.
Is there really no better use for it, where it even may be considered as a value? If not, we are running a high risk that many boats and other fibreglass products in future will end up in the sea as an additional waste load.
GE reports about some recycling of wind turbine blades, which may be true or just to reassure some critics. However, I fear that there will come a lot of none recycled fibreglass waste to nature.
As building riffs with waste fibreglass materials was suggested as an alternative I would like to point on this study which states in its conclusion: "Evidence of matrix and interphase contribution in environmental degradation is shown by crack density measurements, transverse strength degradation, and fiber surface morphology."
Even when it decomposes slowly and takes some hundred years to do, that doesn't make it better for the ambient.