I gotta big Rudder problem (Charlie Cobra)

[w1651]

Hunter 37 Rudder

Looking at a hunter 37 with a bent rudder. Cheapest one I could find online was about $1500.00.
I was thinking about taking it out since the boat is on the hard and splitting the rudder at the spade and removing the shaft. Getting a shaft of stainless to replace it and having it machined to original specs. putting it back into the spade and fiber glassing it together again.
Has anyone ever done this?
Also after I did this how could I protect the rudder so it didn't happen again?

Thanks in Advance

[scottyt]

if you get the shaft out of the rudder a machine shop should be able to straighten it. also over at hunterowners.com IIRC there is a thread on fixing a rudder. cost to get it straighten should be less than 200. you total fix if you do it all your self total fix should be less than 400.

do a search here emkay, he fixed his rudder ( hunter 27 ), which had water issues, it might have been slightly bent too.

[DelmarRey]

You don't want to straighten SS. SS work-hardens once bent and may cause micro-cracking bringing it back. I'd just replace the shaft, it's cheap insurance. Chances are it'll have tabs inside that will need to be added on.
I would contact Hunter and find out how the rudders are put together.

Protecting the rudder is as simple as staying away from rocks.

[Boatsmith]

I would not be comfortable with a stainless rudder shaft that had been bent and then straightened.I would not do this work for a customer. It might be ok and it might not.

[centaursailor]

Originally Posted by DelmarRey

You don't want to straighten SS. SS work-hardens once bent and may cause micro-cracking bringing it back. I'd just replace the shaft, it's cheap insurance. Chances are it'll have tabs inside that will need to be added on.
I would contact Hunter and find out how the rudders are put together.

Protecting the rudder is as simple as staying away from rocks.

Saw simlar advice in PBO(UK) mag.
Agree stainless steel rod is not great once bent and straightened. Tends to be brittle were heated or stressed.
Safe sailing

[sailingdog]

Just remember, most rudder shafts aren't just a straight shaft. They're welded to a web that is the framing the rudder is built around. Without the web, the rudder quadrant has no leverage on the rudder blade, and the chance that the rudder blade would just spin around the shaft is almost guaranteed.

As for how to protect the rudder.. stay in DEEPER WATER.

Originally Posted by w1651

Hunter 37 Rudder

Looking at a hunter 37 with a bent rudder. Cheapest one I could find online was about $1500.00.
I was thinking about taking it out since the boat is on the hard and splitting the rudder at the spade and removing the shaft. Getting a shaft of stainless to replace it and having it machined to original specs. putting it back into the spade and fiber glassing it together again.
Has anyone ever done this?
Also after I did this how could I protect the rudder so it didn't happen again?

Thanks in Advance

[scottyt]

yes the shaft can be weakened once straightened but the ones who i have seen that have done this have driven in either a rod or a tube into the old shaft to strengthen it.

[afunytingapend]

I am the odd one out! I believe the shaft can be straightend! Sorry, but I just tend to try and repair rather than replace. SS depending on its type, is fairly ductile. It is not prone to stress cracking. I would say if it is not bent much beyonf 15 to 20% from std then take it to a reputable engineering shop. Ask for it to be "Stress normalised" .This is heating it up to a certain temp and allowing it to cool at a certain rate. Then straighten it. Back in the oven and heat treat it again. Bring it back to a couple of points below its original temper. Should be fine. SS is incredibly tough. Way beyond the properties of mild steel.

[SlowButSteady]

I think afunytingapend is on the right track. A machine shop should be able to anneal the shaft/frame (if necessary). It all depends on how bad the bend is (i.e., how much the material has to be worked), and exactly what grade of stainless you're dealing with. A good machinist should be able to tell what needs to be done.

[centaursailor]

Originally Posted by afunytingapend

I am the odd one out! I believe the shaft can be straightend! Sorry, but I just tend to try and repair rather than replace. SS depending on its type, is fairly ductile. It is not prone to stress cracking. I would say if it is not bent much beyonf 15 to 20% from std then take it to a reputable engineering shop. Ask for it to be "Stress normalised" .This is heating it up to a certain temp and allowing it to cool at a certain rate. Then straighten it. Back in the oven and heat treat it again. Bring it back to a couple of points below its original temper. Should be fine. SS is incredibly tough. Way beyond the properties of mild steel.

Jez, I believe in recycling but no matter what trouble or expense you go to the shaft cannot be concidered as strong a new replacment. Non destructive testing, X Ray, mite convince me but the cost is realy prohibitive unless you have pals in the industry. Rudder shafts take a lot of stress and need to be 100%. Given the original bent I,d be concidering ways to increase the diameter if at all possible or at least additional support such a stronger skeg.
Safe sailing