Nick, I also have a clinker Folkboat. Last year when I took her over she had beeen ashore for about 18 months and did apparently leak quite a bit for the first week or so in the water. This year I lifted her out in December and put her back in about the middle of April; the electric bilge pump was running every 10 minutes or so to start with but after 12 hours that was down to every 20 minutes and after 24 hrs about every half hour. After a month it's now down to about once or twice a day as far as I can tell. If yours is leaking as much as you say when refloating then she may well need some refastening.