Yes, it is a possibility and not something that is required by the law. Since a boat is small, it’s okay to use it without a horn. Even for a group of people, the traditional one is compact and doesn’t allow you to work a horn into that space. However, for safety reasons, it helps to put it to use. You can always choose something small but powerful that can work well for you. If you can’t fit it, you can slide it below your seat to be used as and when needed.