Response from LEGO SHOP
27 July 2020
Marine, Customer Service
Hello,
Oh no! I'm sorry you’re having some difficulty keeping the set together to float. We always test and retest our toys to make sure that they’ll hold up to play when they’re built exactly as shown in the instructions. If your set ever seems like it's not very sturdy, the best thing to do is double-check your build. Sometimes there may be a piece just a little off from where it should be. You’ll also want to make sure that all the pieces are pressed tightly together.
If you'd like a hand troubleshooting the build, or if you find that any pieces aren't holding together as they should, feel free to give us a shout at LEGO.build/Service-BV.