Hi folks, The boatyard noticed a pit in the rudder shaft right where it enters the rudder. The boat is an 87 Hunter 31 and the rudder is from Foss Foam. There was some discussion between the yard and the surveyor and we decided to drop the rudder for further inspection. Naturally, this happened a few days after I read the story in Cruising World about the race boat that broke its rudder shaft (of course, that was carbon fiber and the rudder probably cost as much as my boat) and the same day we were to leave on a 3 day trip through Windy Alley (Santa Barbara Channel). We went on the trip, the rudder didn't fall off, and there wasn't enough wind to make it worth taking the sail covers off (so I further reinforced my lack of interest in ever buying a trawler). Today I dropped the rudder (with the boat in the water, fun job) and there is a small pit, about 3/16" in diameter, maybe 1/8" deep. There is no other sign of corrosion, and while I know nothing about corrosion on stainless steel, it doesn't look like the strength of the shaft is compromised. Can anyone advise me on a couple of items: 1. How much, if any, pitting is acceptable on the rudder shaft? 2. If I leave the area uncovered, can I expect the corrosion to continue or stop? 3. Can I seal the pit with epoxy or something similar? Will this prevent more corrosion or enhance it? 4. Would it be of benefit to drill the pit out (to prevent cracks from radiating from the pit) and then seal the hole? 5. Should the rudder/steering system be grounded? My plan (if blessed after closer examination by the surveyor) is to put the rudder back on (more fun) and drop it in 3 or 6 months for further inspection. If not blessed by the surveyor, it's time for a new rudder unless some corrective action can be devised. Thanks in advance for any and all expert advice. Bob Werner s/v X SAIL R 8
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Karl
Anything that's iffy, I always repair or replace now.. How about filling in the pit with some stainless welding and then grinding it off? Keeping a hose on the rudder to keep it cool. Most boat yards can can do this for you. Why wait until later? Get it done now.
Anything that's iffy, I always repair or replace now.. How about filling in the pit with some stainless welding and then grinding it off? Keeping a hose on the rudder to keep it cool. Most boat yards can can do this for you. Why wait until later? Get it done now.
My advise...
Would be to photograph the area now for comparison later. Attaching a ground wire and zinc guppy would certainly slow down or stop any further electrolysis. This could be done inside the shaft and removed from time to time for inspection (assuming there is water inside). If not, just drop the guppy over the side when your not using the boat.
Would be to photograph the area now for comparison later. Attaching a ground wire and zinc guppy would certainly slow down or stop any further electrolysis. This could be done inside the shaft and removed from time to time for inspection (assuming there is water inside). If not, just drop the guppy over the side when your not using the boat.
Not advice, just my experience
I've got a 1980 33, and it had the common problem of crevice corrosion of the stainless steel rudder shaft and packing nut. I had to have a new packing nut custom made, but just left the shaft as it was (sounds like it was about like yours), lightly polished the pits some to remove sharp spots, and repacked the stuffing box packing with new packing...that was 5 years ago and no drips or problems since...it may fall off tomorrow, but I've had no problems..
I've got a 1980 33, and it had the common problem of crevice corrosion of the stainless steel rudder shaft and packing nut. I had to have a new packing nut custom made, but just left the shaft as it was (sounds like it was about like yours), lightly polished the pits some to remove sharp spots, and repacked the stuffing box packing with new packing...that was 5 years ago and no drips or problems since...it may fall off tomorrow, but I've had no problems..
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