Steering/Rudder problems (and a sagging aft deck!!)

Home Forums Propulsion Steering and Rudder Steering/Rudder problems (and a sagging aft deck!!)

Viewing 5 posts - 1 through 5 (of 5 total)
Author Posts
Author Posts
August 18, 2021 at 16:54 #27005

Guy H
Participant

After some advice (as always)

The steering on Interim has always been a little heavy, but I had assumed that was normal however a couple of weeks ago it became *very* stiff.

I undid the top of the rudder gland (which was very green & dry) and squirted a load of WD40 into the end where the rudder stock come through the bushing. That freed it off to some extent but still not great

I went down this week and it is even worse 😫😫

I removed the ‘gas lockers’ from either side of the mizzen and that also revealed that the aft deck has sagged and that was allowing water under the emergency rudder plate, into the box, then down the shaft and it was this that’s made the rudder gland go green.

Help!! I am feeling a little overwhelmed to be honest
I’ve created an album of photos & a couple of videos Interim’s dodgy steering and I’ve uploaded the main video on YouTube & watching & seeing the rudder stock bend with the strain is making me feel quite ill – I hadn’t realised that was going on

August 18, 2021 at 19:17 #27014

Moderator
Keymaster

Guy, is your boat in the water?

To isolate whether the problem is in the steering gear, or the rudder movement, have you tried mechanically disconnecting the steering gear connection at the rudder post, then use the emergency tiller to rotate the rudder? If you boat is out of the water, you can disconnect the steering gear, then go down and move the rudder by hand.

However, Van just told me his thought after watching the video is that it must be the rudder movement is jammed somehow – that the steering gear seems to be able to apply an enormous force to the rudder post, so the steering gear is fine. See Van’s good blog post on our website about when he rebuilt our rudder, if you want to know details of the rudder construction.

What could stop the rudder moving? Some ideas:

1) Something is physically in the way of the movement.

2) The bottom shoe bearing is stopping the rudder movement.

3) The hinge part is stopping the rudder movement.

4) The packing gland is seized onto the rudder post.

5) The top bearing at the deck is stopping the movement.

In other words, the rudder is held in place by 4 things, and one of them is not functioning correctly. If your boat is still in the water, I would schedule a haulout ASAP because, yes, the rudder post packing gland and where the rudder posts exits the hull is well below the water line.

Just in case you have not had a good look with Interim out of the water, there are several useful pictures of what the rudder looks like when out of the water at the top of this post and within this blog post. And this shows what the  keel looks like when the rudder is removed for rebuild.

August 18, 2021 at 20:22 #27015

Guy H
Participant

Thank you Marilyn for your reply & the links & thoughts etc
She’s still in the water at the moment.

I’m going down tomorrow and will try to isolate it more – last time I was just so fed up with it I wasn’t thinking straight.

Yes, enormous forces are involved as it is bending the bronze shaft before it ‘gives’ and turns a bit. I did mention on Facebok that at least this proves that the rest of teh steering, UJs & mounts etc are in good condition … little wins

The rudder was apparently rebuilt in Iroko & sheathed in glass 5ish years ago, but it is still with the original bronze stock.

The more I look at it I think the main problem is binding in the bush under the packing gland (it’s not the ‘nut’ as that is actually unscrewed in the video.
What is leading me in that direction is the fact that I have removed the nut and there is no lubricating water coming up the bush (that the packing would normally stop leaking)

So, I think my plan is to go down there tomorrow, see if I can isolate the issue, take almost all of the tension out of the mizzen lowers and see if anything moves.

In the short-term I am going to book in a haul out in October (as the prices drop by a chunk) and between now & then I am going to repair the deck under the mizzen step.

August 19, 2021 at 01:24 #27016

Van
Participant

Another comment or two:  the rudder stock is not actually bending.  I can’t imagine that you can bend a 1.375 inch diameter solid bronze bar as much as it looks like in the video.

Looking carefully at the video, what I see is that the top of the rudder stock (in the deck bearing) does not move.  But the bottom, where it disappears from the view, does move.  This looks like “bending” but I think that something else, out of sight below, is moving.

My bet is that what is happening is that the stock is “flexing” at the rudder stock coupler, which is acting like a hinge.  The coupler joins the upper section of the rudder post to the lower section.  The lower section is what is embedded inside the rudder.  The upper section goes to the upper bearing in the aft deck.  The upper section is where the lever arm that the steering mechanism needs is clamped.  Each of these pieces are keyed.  [The coupler is typically horribly corroded and must be cut off with a grinder.  Before you do this, talk to a machinist about how to replace it.  See the link https://svrainshadow.com/?p=1144 for how we did it.  Or, if you are lucky, when they rebuilt the rudder they also rebuilt the coupler, and did not just use mild steel like C&N did.]

As the steering pushes the stock laterally (because the stock does not easily rotate) then the two parts of the rudder stock will angle in opposite directions, so you will end up with a shape like this:  < or >.  (Imagine the upper line is the upper stock, etc).  The top is fixed by the deck bearing, the bottom is fixed by the stuffing box, and the coupler is where the bending happens.

Both the upper and lower parts of the rudder post must be separable in order to be able to remove the rudder when hauled out.  If the post were a single piece, then you would need to drop the rudder several feet (and therefore you would either have to hold the boat that high off the ground, or dig a bloody great hole under the rudder!).

The video shows that you have full range of motion.  That means the rudder physically can move (eg there is not an obstruction).  That really leaves the only causes as being the four contact points for the rudder that Marilyn listed.

You should get a visual inspection of the rudder.  In particular, the shoe at the bottom is made from a bronze part with a pin on it.  The shoe is screwed to the bottom of the keel with several self tapping screws.  The weight of the rudder should sit on this shoe.  If that shoe has failed (dislodged in a grounding, or corroded away to nothing, or the screws came out), then the weight of the rudder will be on a part that is not designed to support that. (The weight is not too bad, as the rudder has some flotation, and is really not that heavy). But whatever is supporting the rudder was not designed to do that, and may be the source of the resistance.

BTW, of course look for dezincification in the rudder stock, but chances are good that it is just fine.  Ours was stainless steel and had crevice corrosion so we replaced it with bronze.

Good luck!

Van

 

 

 

August 19, 2021 at 10:19 #27017

Guy H
Participant

As the steering pushes the stock laterally (because the stock does not easily rotate) then the two parts of the rudder stock will angle in opposite directions, so you will end up with a shape like this: < or >. (Imagine the upper line is the upper stock, etc). The top is fixed by the deck bearing, the bottom is fixed by the stuffing box, and the coupler is where the bending happens.

I think you are most likely right there – in one of the other videos you can see fluid moving in & out of the interface between the coupler & the lower stock

The video shows that you have full range of motion. That means the rudder physically can move (eg there is not an obstruction). That really leaves the only causes as being the four contact points for the rudder that Marilyn listed.

Yes, that was about the only thing I could think of eliminating last time I was there. & then thought of using my camera to ‘see’ what was going on

You should get a visual inspection of the rudder. In particular, the shoe at the bottom is made from a bronze part with a pin on it. The shoe is screwed to the bottom of the keel with several self tapping screws. The weight of the rudder should sit on this shoe. If that shoe has failed (dislodged in a grounding, or corroded away to nothing, or the screws came out), then the weight of the rudder will be on a part that is not designed to support that. (The weight is not too bad, as the rudder has some flotation, and is really not that heavy). But whatever is supporting the rudder was not designed to do that, and may be the source of the resistance.

Thank you, I’ve been looking at your blog posts & now really understand all the bits (except what’s inside of the ‘gland bearing’

The ‘box’ that holds the top/deck bearing has delaminated (you can see it clearly moving at the fwd edge where the 4 bolts are) so I think I am going to concentrate on that (& the sagging deck) as I can do those in the water. A haul-out in October is much cheaper for me & I don’t think anything is going to change in those 5 weeks. If the rudder seizes completely then it’s only about 50 yards in sheltered water to the travel lift for me. I will also use those 5 weeks to run penetrating oil inside the coupler – it’s been painted nicely on the outside so i think it was at least refurbished when the rudder was done.

I’m also going to have a good look at the top bearing and probably get a new one made in acetal whilst I fix the box area.

Thanks again

Viewing 5 posts - 1 through 5 (of 5 total)

You must be logged in to reply to this topic.