I assumed it was like the rowing tubs that the boat clubs here use for initial training. They're sort of clinker, but with very broad strakes; almost like a multi-chine boat.That looks more like carvel than clinker. Do the planks overlap or are they butted together? Stripping the varnish off will reveal a lot more about 5he condition but, as @AntarcticPilot says, there are either rotten or badly racked and will probably need replacing. You also seem to have a rubbing strake over the planks that might need replacing or a least removing.
Sorry I don’t know anyone in that area but there will be people in Gloucester (try the docks area).