FO,We put in all "new design" Forespar thruhulls in '02. Only maintenance is to open/close the valves regularly.
No problems, but I should note that as of that year, Forespar had not yet solved the problem of the ball material being very slightly hydroscopic.... so they are still hard to operate, and I ascribe that to the ball material slightly swelling.
However, these new valves do allow you to back off the screws from the top of the split body and free them up.
Considering that we have no worries about electrolysis, I like these thruhulls.
After all, "Everything's a compromise" as someone once said...
When I worked in the hydronics/HVAC industry as a manufacturers rep we had two lines of valves. I got to tour a few valve factories and one plastic valve factory. The biggest problem with plastic balls is that they are very, very hard to make round. On top of that as you pointed out they can and do swell from time to time. Forespar has gotten the zytel valves a lot better than they used to be but I still see broken handles. The OEM/93 series is better but quirky as they require the special OEM/93 series thru-hull fitting which is NOT a standard thread.
The problem with their flushing seacock is that they state nowhere in the directions that you should NEVER connect pressurized water directly to the hose fitting. Hopefully that has changed. People buy these valves thinking that is what you do, connect hose and turn on.... If you do that you then hydrolock your engine.
After overhearing the Forespar rep at Hamilton Marine explaining to a customer how easy it was to flush your diesel with fresh water by connecting a hose to the OEM/93 series flushing valve, I stood there in utter disbelief. I then asked the rep how exactly he suggested doing it.
"You just connect the hose here (pointing to the fitting) then turn it on and start the engine."
We then had a long discussion about why you CAN'T do that on a wet exhaust diesel. He had no idea.. He then asked if I would call his company and talk to them, which I did. When I called Forespar about the issue, a few years ago now, I asked about placing a warning in the directions, they were stunned to hear that this, hydrolocking, could even happen...
Amazing really...Great idea that needs to be carefully executed in the field by customers or you can severely damage or destroy your engine..
