Aqua Kong

There's a bit of a crisis in Ross' world.. the foam core has gone out of the precious Aqua Kong .. so now it sinks. Any ideas? I've stuffed it with a sponge, you know the things you get in medicine bottles, but as Steve says it will probably fill up with water and sink! But I had to try. Maybe I'll take it in the bath with me tonight to see. And you think I'm joking???
I have contacted "Kong" and got an automated response .. they will get back to me within two weeks, no rush then! Thank god we have a spare!  To keep them precious Ross only has the kong on walk so he can not be accused of pulling the core out, actually it was there when we set off for Llyn Ffynhonnau yesterday and lost on route. Not good really is it .. damn thing is no bloody use if it doesn't float, anyone got a snorkel he can borrow?