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View Full Version : rudder base failure!


pilot02
08-13-2006, 03:36 PM
Just curious if anyone here has heard of or seen the rudder base (mount) fail WITHOUT an impact.

Had it happen to me yesterday on my 89 tristar 190. Realized the steering was stiffer than normal at speed and thought the cable was probably failing considering the age of the boat but upon further inspection realized the support tube for the rudder had failed at it's base and the rudder could actually be moved in a circular motion more than an inch.

Dan K
08-13-2006, 07:07 PM
That's a new one. I never saw or heard of that before. Is the history of the boat known. Maybe, it was hit before and the rudder was replaced and this base was overlooked or not completely cracked then.

Farmer Ted
08-13-2006, 08:17 PM
Thank god you didn't get an uncommanded yaw.....

phecksel
08-13-2006, 11:35 PM
Any chance for a close up on the failed parts?

michael freeman
08-14-2006, 07:20 AM
Could it be one too many power turns or what ever they are called when you slide the back of the boat around?

Only other thing I could think of is a small perturbation/vibration over time causing it to crack.

pilot02
08-14-2006, 09:38 AM
Any chance for a close up on the failed parts?


I'll try to post one this evening.

jclose8
08-14-2006, 10:49 AM
EXACTLY the same thing happened on my buddy's Toyota. Not sure what , if anything in particular, caused it.

pilot02
08-22-2006, 04:08 PM
More detail. Definitely looks like corrosion and there appears to be a cut into the base from where it was originally machined.

pilot02
08-22-2006, 04:09 PM
Anyone know about the changes in design of the rudder port? The new one is larger, doesn't have a grease fitting and will require the hole in my hull to be opened up some. See below....

erkoehler
08-22-2006, 04:18 PM
Just start cutting away the hull:D

pilot02
08-22-2006, 04:40 PM
Just start cutting away the hull:D

I hear ya......

92 190 PS
08-22-2006, 04:45 PM
Just start cutting away the hull:D:huh: :eek3: :shocked:

Erk you are wrong....

JimN
08-22-2006, 05:06 PM
Make a plug that has its center marked and use a compass to draw a circle around the old hole, of the size needed for the new fitting. You don't want the new hole to be sloppy- it needs to fit well to add support to the sleeve. If you want to use a hole saw, go ahead but make sure it's going to give you a hole of the right size. Use a piece of plywood or other wood, cut a hole of the right size in it and mount it so it's plumb to the hull either by using spacers or actually cutting the wood to the shape of the hull with a bandsaw or something like that. If you can get to the area of the hull where this needs to go from the inside, the hull is flat and you have room for a drill and hole saw, make a plug, glue it in and cut the new hole.

M-Funf
08-22-2006, 05:29 PM
Make a plug that has its center marked and use a compass to draw a circle around the old hole, of the size needed for the new fitting. You don't want the new hole to be sloppy- it needs to fit well to add support to the sleeve. If you want to use a hole saw, go ahead but make sure it's going to give you a hole of the right size. Use a piece of plywood or other wood, cut a hole of the right size in it and mount it so it's plumb to the hull either by using spacers or actually cutting the wood to the shape of the hull with a bandsaw or something like that. If you can get to the area of the hull where this needs to go from the inside, the hull is flat and you have room for a drill and hole saw, make a plug, glue it in and cut the new hole.

I agree with Jim. Glue in a plug and drill the right size hole in the right location.

It looks like there's quite a bit of "green" corrosion on the fractured surface of the old part, leading me to believe that water was in contact with that surface for some time. To me, that says this was probably a fatigue failure that occurred over some time.

You may want to check to make sure that the joint attaching the steering rod (the one that attaches to the arm on the top of the rudder) to the arm of the rudder rotates freely (should be something like a ball and socket joint??)

If that joint is sticking, it will push the shaft of the rudder off-axis each time you turn the steering wheel, which would eventually break something...

mpm32
08-23-2006, 01:02 PM
One way to drill a larger hole using a hole saw is to find the right size for the original hole. Insert that into the larger sized holesaw (doulble them up) and the smaller one will guide the larger one. No need to glue in a patch.

TMCNo1
08-23-2006, 01:12 PM
The side notches on a large Vari-Bit can be used to grind away the excess fiberglass to make the hole larger, no more than you have to cut away. Been there! Be sure to seal the hull flange and the interior with marine silicone to assure a good seal, including the bolt holes.

JimN
08-23-2006, 01:16 PM
mpm- that works if a longer saw of smaller diameter can be found and the mandrel is also long enough to accept both. Some are, some aren't. The tricky part is to drill straight up (or down) through the old hole. A core saw might work for this since they're made for concrete and won't cut fiberglass as aggressively as a regular bi-metal hole saw.

pilot02
08-24-2006, 10:01 AM
Thanks for the suggestions but the major part is already done. Turns out there was about an 1/8" of silicone surrounding the previous part so the hole only needed to be widened about a 1/16 of an inch. After carefully marking a high tech popsicle stick to the width of the new part and marking how far I neede to widen, I used an air powered die grinder with a rasp bit and it took all of 15 mins and the fit is nice and snug. Would have finished it off last night but was out of 5200 (or is it 4200? Can't ever remember which one is for below the water line...) Anywho, to make a long story short, it will be back together tonight at which point I'll make the decision to replace the steering cable/assy if necessary.

Tom023
08-24-2006, 11:24 AM
Pilot, you may want to reconsider using 5200, as it is an adhesive as well as a sealant. The issue becomes if you ever need to remove the rudder port again, the 5200 is very difficult to remove and can actually tear the gelcoat and fiberglass off rather than comming off clean. 4200 on the other hand has a bonding strength half of 5200 so disassembly is possible and is good above and below the waterline.

pilot02
08-24-2006, 01:28 PM
Pilot, you may want to reconsider using 5200, as it is an adhesive as well as a sealant. The issue becomes if you ever need to remove the rudder port again, the 5200 is very difficult to remove and can actually tear the gelcoat and fiberglass off rather than comming off clean. 4200 on the other hand has a bonding strength half of 5200 so disassembly is possible and is good above and below the waterline.

Good idea! I was thinking one of the two wasn't supposed to be used below the waterline though.