So as it turns out those kids sandboxes are actually quite water capable : r/pics
Amazon.com: Costzon Kids Sandbox with Cover, 4ft x 4ft HDPE Sandpit with Oxford Cover, Bottom Liner, 4 Corner Seats, Weather Resistant Outdoor Sand Pit for Backyard Lawn Garden Beach (White) : Toys
This Little Tikes Tuggy Sandbox Is Now a Real, Legally-Registered Boat
Kid turns toy sand box into fishing boat! - YouTube
This Little Tikes Tuggy Sandbox Is Now a Real, Legally-Registered Boat
Amazon.com: HONEY JOY Sandbox with Cover, 4FT Round Sand Pit for Backyard, 3 Built-in Seating & Bottom Drainage Liner, All Weather Resistant Sand Boxes for Kids Outdoor with Lid : Toys &
Step2 tuggy the boat sandbox toddler kids swimming pool for Sale in San Marcos, CA - OfferUp
Little Tikes Tuggy the Tug Boat Sandbox Pool for Sale in Saint Petersburg, FL - OfferUp
Rescue Tug Boat Children's Kid's Toy Beach Sandbox Boat Playset w/ Toy Boat, Hand Tools, Sand Molds (Colors May Vary) - Walmart.com
Tuggy sand box and pool & slide for Sale in Hayward, CA - OfferUp
Melissa 3.5'' x 3.3'' Plastic Novelty Sandbox | Wayfair
Beach Toys Sand Kids Boat Bath Bucket Kid Play Summer Set Playing Castle Floating Party Water Pool Sandbox Toddler Mold - Walmart.com