Dear atexasex...I know your question was last year...but I recently found a repair method for the tanks in recent (I know at least as early as 2000) Hunters. The tank material used is High Density Poly Ethylene (HDPE). Mine on my 2001 460 were produced by Dura Cast in western Florida. The diesel, water and holding tanks are all comprised of HDPE. Look on the bottom of a milky white type gallon water bottle...you should find HDPE within a triangle. That is the stuff.
I contacted Dura Cast and they recommended using a 3M glue product called something like DP 4200. I tried to use it to creep into a crack in a water tank. It worked marginally...Dura Cast was not very excited telling me about it but suggested it when I told them removing the tank was really difficult and would try anything. When I used it, it seemed very similar to the material where they glued in fittings to the tank. Probably best used between surfaces compressed together rather than just as a surface sealant or as I tired to press it into the crack.
Then I came across a You Tube video on plastic kayak repair. There is a link to a company that sells Urethane welders (it is very similar to a soldering gun but I think the temp is much lower). With this welder and water bottle material, you can make just about anything. Most notably, a patch for your tank or just melt more material on. They even have a stainless screen material that works in the same concept at glass matt in glass resin to strengthen an area. The process is slow and tedious, working very small areas at a time. But I saved my tank at low cost and only an expenditure of time on my part. All the best, Tim at Cruising Spirit
