Welcome to the forum.
We'll probably need a little more information to give a proper answer, plus pictures. If you photograph the serial build plate, that will confirm.
Most leisure Zodiacs with solid GRP hulls use a bolt-rail system, so the tube sponson slides on. Certainly on 2006+ on models, there was a separate strap on the bow tube to the towing U bolt to maintain tension. Similarly on the transom, there were two tightening straps. If you think water is entering under the tubes - you'll need to retrieve the boat to investigate. There are cases where the bolt rail detaches.
On pre-2000 RIBS such as Pro 530 for example, there was a lace-cuff that fastened to the hull around the bow.
The anchor locker or bow locker is not watertight, as far as I'm aware. There's no rubber weather-strip and can be bailed.
Regards barnacles, if you're on permanent mooring, you can go down route of antifoul or copper-coating, however do your own reading on the pros and cons. If barnacles and other crustations are already fouling the hull or tubes that make contact with the water - you'll need to retrieve and power-wash, then follow with treatment of diluted oxalic acid. Test small-area on tubes.
Sula
