OK Looking at the info that HMSAntrim kindly posted.
I am making a few assumptions here.
There is probably a slot in the bottom of the hull to seat the keel. The keel may not be fully home.
There is a keel tube running up through the hull. This may not be correctly aligned, especially at the top where it joins the deck, this can be hard to spot. Popping an awl, or similar into the hole in the deck is the easiest way I have found to re-align the keel tube if it is out.
Also the deck is flexible, and may need pulling down to the keel tube. If the keel tube is glued in, a blob of glue could be affecting alignment. As long as the keel tube is sealed at the bottom she should be water tight.
It is possible it is a manufacturing issue, with the steel rod moulded too far down into the keel. But with Kyosho this is highly unlikely.