Why my rudder gets stiff?

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cmedsailor

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While sailing if there is a lot of pressure on the rudder (because of rough sea) it gets stiff to turn and when turning it makes a noise like something is rubbed. The boat is a Beneteau Oceanis 361.
Any idea what is wrong?
Thanks
 
It sounds like the lower bearing of the rudder stock has disintegrated. This is sometimes caused by pitting of the stock itself. I suggest that you inspect it when you have the opportunity. Changing the bearing itself is not a big deal but it needs to be done on the hard.
 
On the 351, the predecessor, and I think they are the same, there is a nylon bush on the top of the rudder stock and a bronze bush at the bottom just above the rudder, they are top hat bushes and are a push fit into the glass fibre housing. There is a plastic thrust washer between the rudder and the flange of the lower bush. The bronze bushes can and do work loose and drop down but are held in place by the top of the rudder. The plastic thrust washer could have worn, the bushes could be worn, the rudder shaft is a glass fibre shaft and is held in place by a collar and a bolt/pin thru this and the shaft. Go in to the sugar scoop with a torch and have a look to see if there are any worn bits etc, otherwise wait until you lift out to check the rudder fit in the bush, or if the bush is loose. Easy enough to change all the bits, but need to be out of the water and in a lift to drop the rudder. If the bronze bush has dropped you can knock it back up and drill and tap the rudder housing to fit grub screws as a semi temp repair.
 
We've had exactly the same problem on our Hunter Legend 420 passage. All season the steering has been getting stiffer and stiffer, but only when under a lot of engine power, or when over canvassed. Finally coming into La Coruna in Spain we found out why - the rudder stock broke at the top bearing and it cost us 380 euros for a tow in!!!!

The fibre glass stock had slowly delaminating and twisted itself to pieces so when under pressure the shaft was misaligned and the bottom bearing seized. There are score marks where this has happened. As soon as we released the engine power, or depowered the sails all was fine. The sounds you are hearing could be the final death throws of the shaft with delaminated fibreglass grinding against fibreglass.

Hunters shave a history of this - maybe Beneteau too - I suggest you remove the rudder and have a look before it fails at an akward moment. That's sometimes easier said than done, it took me two days to remove the pin that held the stock into the quadrant, because it was a stainlees steel pin into aluminiumn. Sometimes these have to be cut out. Because we had nothing to loose we did manage to remove the rudder whilst still in the water with the help of a diver, by weighing down with an anchor and floating it out. You just have to get the ballast right, and make sure you don't loose and shims or washers between the rudder and hull. We are lifting out on Monday to fit the new rudder - Hunter now make them with a stainless steel stock!! The whole episode has cost us a month wasted time in La Coruna, and about 5000 euros.

We have now chopped up our old shaft and it looks like a bad lay-up of the fibre glass with folds and air pockets over a foot long could have reduced the strength dramatically. I'm taking the bits back to the UK at Xmas for expert analysis.

And one last comment the Insurance company have turned down our claim because they can't identify an "insured peril." The rudder is not damaged so we don't appear to have hit anything!!!!
 
Yes it could be any of the above - though I think Benes have steel shafts. It could be just dirt/salt in the top bearing so as a quick fix a kettle or two of hot water poured over the bearing may help.
Another option is that the bearing is nylon and has swollen over time -it absorbs moisture - lubricate with teflon may help - don't use oil/WD40 s this will make it worse!
 
Yes the vertical shaft is made of GRP - lots of racing boats use it for lightness - maybe its cheaper also - but is dangerous if you have had a manufacturing fault in the layup.

Just as a sidenote we are lifted out of the water and the new rudder doesn't fit by a long long way. We are having to cut off and rebuild the bottom bearing. Not easy when you are in a foreign country!
 
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