The non-refundable deposit goes to reserve your spot and cover certain fixed cost, like pool rental, insurance and assistant instructors. It's a two-way guarantee that you will do your best to attend, and that I will save a spot for you, provide you with a properly fitted kayak, and provide assistant instructors as needed, to keep the Student to Instructor ratio in check.
If you cannot attend, try to find someone who can take your spot, and work the deposit out between the two of you. They should contact me as soon as possible to ensure space is avaialble, and provide me with their height and weight, so I can bring the right sized kayak.
If, and only if, a class is full, can the deposit be refunded, or transferred to a different date.