Not fully understanding Alans comments about antifreeze in the bilges for winter storeage, I opted for the dry and dusty option for under the deck. So at lunchtime I opended up the hatches only to find a pint of Petrol sloshing around at the stern. After stubbing out the ciggy I pondered on what to do next.
The boat is a Ribtec 6.45 with twin 30 gal fuel tanks underdeck. I do remember over filling the front tank about a month ago as the vent is the same height as the filler. But why did it take so long to work its way through? Investigation through the rear hatch showed a small plastic tube under the rear fuel tank up to the bow to drain the middle of the boat. Excellent, if I cut a small hole above the front tank and put the garden hose down there, I will flush through any remaining fuel. After drilling a small hole and checking the underdeck clearance with a piece of welding rod (less I cut through the tank) I set to work with the tank cutter narrowly missing an underdeck beam.
Before using the hose though a bucket of hot soapy water might help, so down it went and I sat back to see the results. 10 minutes later (another ciggy) nothing! ablsolutely nothing. EEK! were did the water go? Hmm, ignoring that problem I then used the hose on the hot water tap to wash out the stern, filling the hose with "jif" before filling the plastic pipe in the bilge. An hour later only a slight film of petrol could be seen. So now I have a bucket full of water in a compartment I cannot see and a wet stern compartment. Oh yes and a 2" hole in the deck waiting to be opended up and a permanent hatch fitted. The boat is now up ended inside a workshop hopfully drying out.
On reflection the petrol is likely to have leaked from the main filling hose past the jubliee clip down between the deck and the GRP join with the hull. Therefore this and the vent will have to be replaced along with re routing the vent higher. the bucket of water though is another problem and possibly solved by cutting another hole and using a hair dryer. Unless you have another suggestion. (The only thing that can be seen through the hole is the tank with a gap of 1.5" under the deck).