Hurth Problem Resolved E-38
At long last I can report on the CLUNK (and slam) I was hearing when shifting into forward. Thanks to Cory, Main Sail and Loren for chipping in their comments, if there were a prize it would go to Cory for his suggestion which hit the mark.
Although Cory suggested looking at the feathering prop, I started above water thinking it was the transmission. I called in the local Universal and Hurth specialist for his opinion. He gave the transmission a clean bill of health but noticed the engine mounts were loose, so he took the opportunity to align the shaft to the engine and adjust the mounts. There is no doubt in my mind that this service was needed, but the annoying clunk was still very audilble.
Next I had the diver who cleans the hull monthly look carefully around the feathering prop. When he pushed and pulled and moved the prop around, he noticed a gap could form between the two hub assemblies.
Next I contacted Martec for their opinion. They were fairly certain that three internal bolts worked loose allowing the prop assembly to pull away from the shaft assembly when put into reverse, then when put into forward the prop assembly slid forward making hard contact with the hub assembly, possibly resulting in the loud clunk I was hearing.
Martec's assesment was correct, the problem was resolved without having to haul the boat. The key was a good diver and a long "T" handled 5mm allen wrench to reach the bolts which had worked loose. Working under the boat he was able to keep every thing aligned and secure the bolts.
What caused the screws to loosen? I had a drip-less and new shaft installed at my last haul-out in 2008, upon re-assembling the feathering prop, the yard failed to use "red lock-tite" as specified in the instructions. With time the screws worked themselves loose.
All is well that ends well, so I'm a happy camper and sailing again.
Don Taugher
Running Free
E38-200 # 263