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| Rudders locking up http://www.hobie.com/au/en/forums/viewtopic.php?f=13&t=11395 |
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| Author: | SicosDave [ Tue Dec 16, 2008 6:59 pm ] |
| Post subject: | Rudders locking up |
Hard to explain, but my rudders tend to lock up - have to use extreme force to turn to prevent bearing away. Have checked rudder alignment and is correct. At times it happens when on trapeze and I bring the hull back into the water (Gust disappears etc), and other times when a gust hits. I am too slow to release jib as am solo, leeward hull goes under water and rudders start coming out of the water. It does not matter where I am standing, middle or aft. Have been told it is cavitation but does not happen predictably. Tired of the sight seeing trips around the main while on trapeze. Have noticed ring dings on rudder pins starting to dig into casting - will be fitting a washer to prevent this. Are there other settings one can try? |
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| Author: | ncmbm [ Tue Dec 16, 2008 7:46 pm ] |
| Post subject: | |
I really don't follow you. The rudders don't actually lock up do they? As in they are frozen/locked in place? Or is it just extreme helm? If you drop the tiller where does the boat go? Hopefully to weather, points up and stalls. Give me some info and it can be figured out. One of my first impressions is your mast is too far forward. Improper mast rake can really effect the rudders. |
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| Author: | MUST5429 [ Tue Dec 16, 2008 8:42 pm ] |
| Post subject: | |
Dave, I too am a bit confused by the description of the problem you are having, but if I correctly understand what you are trying to say, it sounds as if you have problem with what is commonly called "lee helm" Lee helm is when the boat wants to fall off rather than head up into the wind when the tiller is released. If that is indeed what you are experiencing, try raking the mast back as far as you can. Loosen the forestay to the very top hole, then take the shrouds to the bottom hole in the chain plate, and then reset the forestay where ever it ends up so that the tension on your standing rigging is about the same as you normally set it. Go ahead and rig the rest of the boat just as you normally do. Making more than one change at a time will only confuse you. If you make multiple changes, it is hard to know what effect each individual change might have on the way the boat is sailing. That will move the center of effort almost as far back as you can get it, and you should have a significant amount of "weather helm" in other words, if you let go of the tiller when sailing "to weather" it should round up "to weather" like a bandit, and voila, your problem will be cured. If that "cures" your problem, then you can start moving the mast back forward in small steps, one or two holes at a time. until you have only a slight weather helm and (Note if you move the shrouds up one hole on each side, you can usually take two holes down on the forestay) The object of the game in making such a radical adjustment in the first place is to change things so dramatically that the change in the "feel" of the boat will be very noticable to even the most casual of observers. If it cures the problem, then you can start "fine tuning", moving the mast forward to find that "sweet spot" where the boat has just enough weather helm but not so much that it wears you out. You may make additional changes later as your feel for the changes in the boat become a bit more "educated" Hopefully that will help you resolve your issue. Stephen |
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| Author: | SicosDave [ Wed Dec 17, 2008 3:58 am ] |
| Post subject: | |
When sailing and for example I let go the tiller to pull in the main she heads into the wind. The force on the tiller is easy, no binding etc. But as the wind gets stronger or a gust hits then the force required is more than for example while coming in to shore with the rudders up and trying to steer. I am busy sailing steering is ok then all of a sudden you push and it does not move, I really have to shove or pull. When I have a victim on board it does not happen as often but does happen usually at the worst possible time. When solo standing on trap right at the stern, I cannot move further back it still occurs. I initially thought it was the jib pulling the bow around causing lee helm and rudder lock, but have released jib to test and same story. Will try this weekend with different mast rakes, as we did set stay tensions etc so that the bow will not bury easily. Thinking about it, I do believe my mast may need to go back more. Did not think it was an issue due to having weather helm. Thank You Dave |
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| Author: | J_Eaton [ Wed Dec 17, 2008 7:32 am ] |
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Quote: When sailing and for example I let go the tiller to pull in the main she heads into the wind.
This is called weather helm...she "heads into the wind" (aka "to weather") With that confirmed see Stephens post to correct. |
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| Author: | mmiller [ Wed Dec 17, 2008 11:06 am ] |
| Post subject: | |
You also may have weather helm going to weather and lee helm when sailing off the wind... or even different helm on different tacks. |
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| Author: | ncmbm [ Wed Dec 17, 2008 2:11 pm ] |
| Post subject: | |
I'm still confused. Are you saying that if the wind is up and you are flying a hull that the rudder is easy but if both rudders are in the water in the same wind the rudder is hard? |
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| Author: | mmiller [ Wed Dec 17, 2008 2:22 pm ] |
| Post subject: | |
May be a matter of the rudders staying in place... forward in the castings? As the boat accelerates, maybe the rudders shift aft due to the increased speed... that would increase the load / weather helm. Check how much load is required to pull the rudders aft (on dry land). If there is "slop" and the rudders shift aft easily... this is adjustable or the cams may be worn. They need to stay locked down and forward in the castings for consistant helm. |
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| Author: | SicosDave [ Wed Dec 17, 2008 3:26 pm ] |
| Post subject: | |
I learnt the hard way with the H16 rudders, so I did check and they are fine. I also lubricate them with a Q20 lubricant, plus the tiller mount points. My tillers have the bolt through, not the tiger type and have the metal cams not plastic. The rudder castings have not been broken and rewelded. The problem is where I sail the wind is not constant and very variable. So to get accurate testing is difficult. With both hulls in the water I do experience the same lockup/hard to move tiller. It is not predictable, I can fly a hull no problem then next time I get a lockup. On land with the rudders up the wind blows them side to side with no problem. I have weather helm on both tacks. I do notice the hulls do move slightly up and down, was gonna correct this when sending boat in. Will have to wait for the weekend to test, wind permitting. Thanks |
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| Author: | mmiller [ Wed Dec 17, 2008 5:02 pm ] |
| Post subject: | |
Check the "Toe-in" Adjust the length of the rudder blades to 1/8" closer together than the trailing edge. If the rudders wander to a "toe-out" position you can also have stiff / inconsistant steering issues. |
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| Author: | alfred_new [ Wed Dec 17, 2008 6:35 pm ] |
| Post subject: | |
On my H16 I had similiar situation. It turned out that left & right rudders were reversed. Have checked this? |
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| Author: | ncmbm [ Thu Dec 18, 2008 9:02 am ] |
| Post subject: | |
I think Matt Miller is on to something. The only way the rudders can lock up is for something to bind. This is a very simple system, little can go wrong. I would completely disassemble the rudder system and check each part. It could be a bent rod that moves around and binds. It could be the bushings are worn and slop allowing a bind. It sounds like it only occurs when the rudders are loaded sideways. Maybe try pulling left or right on the tip of the rudder and turn back and forth. Also check the crossbar for stiffness at the joints, replace the metal washers with plastic. I really can't think of any other way for the rudders to jamb or lock. |
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| Author: | SicosDave [ Tue Feb 03, 2009 12:36 pm ] |
| Post subject: | |
Thanks very much guys for the suggestions, my pc died so sorry for no reply sooner. Long story short - tried all ideas etc - found rudder had been previously drilled off centre at bottom causing binding under load. Have replaced bushes and pins and had casting welded and redrilled. No issues yet - too busy playing with spinnaker. Thank you Dave |
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