New Rudder

[machone]

My rudder, shown above, is a flat steel sheet welded to the post that goes right through the hull to the tiller. The whole thing is one piece. The tube the post goes through is corroded and needs replacing, as does the lower underwater cup and bushing. There is nothing wrong with the rudder itself or the post. However, without lifting the boat high or/and chopping off the aft piece of the keel I can't work out how it could be removed in order to replace the tube it goes through.

The plan at the moment is to cut the post just beneath the hull and replace the post, welding the old rudder to a new post. Another idea I had was to use square section for the piece of the post shown so that a shaped rudder welded to a square inner section tube could be attached. However, it did occur to me that there probably was a reason for splined shafts. My question is, how difficult(read expensive) is it to put splines on a shaft or to get a ready made splined shaft with associated tube? An initial internet search told me 'difficult'.

Thanks

 

[sarabande]

can you replace it from the top downwards, i.e. remove the tiller, cut the shaft just below th ehull, an dlift the piece upwards ?

 

[machone]

Yes, that's the intention, but it wouldn't be a good idea to replace it in reverse ie. weld just below the hull - a bad place and a weak weld for an important bit!

 

[Tranona]

Cut the back end of the skeg off and fabricate a removable shoe, bolted to the remains of the skeg and use a replaceable Delrin lower bearing. That way you can drop the rudder by just lifting the boat in slings and removing the shoe. That is the arrangement I have on my boat, although a bronze shoe and a wooden skeg, but principle is the same.

 

[onesea]

Cut the back end of the skeg off and fabricate a removable shoe, bolted to the remains of the skeg and use a replaceable Delrin lower bearing. That way you can drop the rudder by just lifting the boat in slings and removing the shoe. That is the arrangement I have on my boat, although a bronze shoe and a wooden skeg, but principle is the same.

Another thought on same idea is cut the post above rudder, remove rudder from below (IE cut low enough to you have space to lift rudder our of shoe). Then drop post out of hull.

When getting new post fabricated have flange's made so that you can disconnect rudder blade from shaft (4 bolts on my last boat with one flange threaded and lock nuts). This means you can disconnect and remove rudder easily, on my last boat I used to do it between tides easily.

 

[William_H]

Is it possible to lift the rudder so that the bottom bearing is disconnected? If the top bearing is then disconnected from the hull it should be possible to cock the whole rudder to one side and drop it down. You might need to dig a hole for it to drop into.
That I would have thought was the way the rudder was fitted so surely it can be removed the same way.
I would, if I were you be thinking about building the rudder face up with GRP to make a decent foil shape. Obviously get the real problems sorted first. good luck olewill

 

[oldsaltoz]

Cut the back end of the skeg off and fabricate a removable shoe, bolted to the remains of the skeg and use a replaceable Delrin lower bearing. That way you can drop the rudder by just lifting the boat in slings and removing the shoe. That is the arrangement I have on my boat, although a bronze shoe and a wooden skeg, but principle is the same.

+1 (What Tranona said)

 

[pampas]

Cut the top 1/2 of welding with a thin cutting disc, fair up the stock and pull out from the deck. lift rudder blade from lower pintle , reverse for fittind and weld blade to shaft. Well thats what I would do. Best of luck which ever way you do it.

 

[machone]

Thanks for the posts.

I've cut the post below the hull with a thin bladed grinder as suggested.

I'm going to get a new tube welded in and also have a splined post made - the splined bit beneath the hull. I'm then going to weld a better aerofoil shape around the sleeve, the idea being to drop the splined shaft into the sleeve and securing it with a couple of grub screws. It will then be pretty secure and also removable if required.

I considered the removable skeg shoe but the boat would still have to be high for it to drop out or in.

Thanks

 

[oldsaltoz]

I considered the removable skeg shoe but the boat would still have to be high for it to drop out or in.

We used to dig a hole before parking the boat.