(27)In accordance with the principle of subsidiarity, the provisions of this Directive should not affect Member States’ entitlement to lay down such requirements as they may deem necessary concerning navigation on certain waters for the purpose of protection of the environment, including from noise pollution, the fabric of waterways, and ensuring safety of waterways, provided that those provisions do not require modification to the watercraft which is in conformity with this Directive and that those provisions are justified and proportionate to the objectives to be achieved.