Hello Dan,
I think I can help here. I did exactly this for a couple of years in Melbourne and made a very moderate living. I hope it will be more popular where you are.
Basically there are two ways to approach this.
Method 1.
Get the pool staff to advertise then book your services to potential clients in the weeks leading up to the day. I had generic posters made up to hang around the pool then attached tailored details for each day/pool.
On the big day you are given a booking form filled in by the pool staff. This will include client details, appointment time etc. If you organise a deposit system it is more likely people show up.
The thing about this system is higher percentage of purchasers, but volumes are low.
Method 2.
Again advertise leading up to the week, based on weekly lessons that is, using posters, pool staff including the instructors. Then attend every lesson photographing every child. Dont' worry about their details. When you return the following week to do the sales, do the sales yourself, I initially got pool admin staff to sell while I went on to the next pool, bad idea, they don't care. Anyway, when you return to sell, you will be approaching parents at the side of the pool so wear something that identifies you as the uw photographer, all you need to ask is their child's lesson time, boy or girl? Your folders on your laptop are organized according to shoot time, from the meta data, and boy or girl. Let them scan the images in the relevant folder for their child. e.g. 9.00am lesson boy folder.
The thing about this method is large volumes but lower percentage of sales. It gets hetic in the water as there are often more than one lesson/ instructor at any given lesson time.
Actually the method may not even be your choice. Often the pool swim lesson co-ordinator leans towards one or the other.
The pitfalls.
In this day and age people will protest against you photographing their semi naked child.
Laptops near a moist pool environment
Most children wont open their eyes underwater, or look generally uncomfortable, hard to sell
Self conscious kids tell parents don't buy it, just as the parent was about to. So the younger the better.
Parents carry little or no money to the pool. They are hot on the idea but never chase you up so get their contact details.
Stage parents coaching from the side of the pool consume more time than the sale deserves.
Some pools will want a commission, fair enough.
I was charging $7 for a 6x4 including negative and some parents would bauk at that! Usually the ones in suits.
I had none of the digital luxuries, I was doing it in the days of film. I had to print the photos to show parents before they would commit to a purchase. Lots of waste.
Getting out and changing film every 36 shots!
Slates and frame counters haunted my dreams.
It should be a walk in the park for you.
You may laugh at this comment now..... but sharks are easier.
HTH
Mary