Hi.
I used to build clinker dinghies inthe 1960's. D Noonan is right, dont try caulking! you will crack the planking when you try driving caulking into a clinker hull, this is for carvel built boats.
Sea water is the only quick solution, best applied by sinking in a mud berth for a couple of weeks. Once she has taken up, keep her wet, but with sea water, not fresh. Fresh water will rot her planking fast. Once she has taken up, leave a little salt water in the bilges, say up to the floor boards, not too full, especially if you take her out of the water as the water load will try to spread her hull, possibly with disastrous consequences. Keep the sun off her with a cover - sun does even more damage to wooden boats than water ever can, especially if they're varnished.
If she doesn't take up after 2 weeks awash in sea water, the only solution is to dismantle her and rebuild her, replacing any rotten or broken frames and planks and fastening her with copper nails riveted onto copper roves inside - that's a job for a shipwright.
Hope this helps, and don't pay attention to people who don't understand wooden boats and tell you to caulk or sheath with fibreglass. As others have pointed out, this will kill a clinker boat!
Peter Wright, October 2010