A written risk assessment is one of the few pieces of club paperwork that does real work for safety, insurance and committee accountability all at once. RYA affiliation expects member clubs to operate sensibly around foreseeable hazards, and most affiliation packs ask whether a current risk assessment is in place. Insurance providers ask the same question at renewal, and the answer affects both cover and premium.
Beyond the paperwork, the assessment exists to protect your members. Sailing puts people on cold water, in fast boats, around heavy equipment, often with juniors involved. A documented, reviewed assessment is what turns "we always do it that way" into something you can actually defend. When a member raises a concern at the AGM, you can point to the document, the review date and the named owner. That is a much stronger position than relying on memory.
Committee accountability matters too. Volunteer trustees and committee members carry a duty of care. A clear risk assessment shows that the committee has thought about the hazards, agreed controls and made decisions transparently. If something does go wrong, a regularly reviewed document is the single most useful piece of evidence you have.