Plunge into the Pirate Pool by Caryl Hart

It's rainy and cold, and Albie's so tired that he doesn't want to go swimming. But when, Albie dives into the pool he finds himself swallowed by a shark-shaped submarine! He realizes these won't be any swimming lessons because this is a pirate pool! Join Albie as he goes on a underwater treasure hunt, meets scary underwater creatures and makes some pirate friends - swimming has never been so much fun!
Binding: Paperback / softback