[quote. . .Where is yours breaking? [/quote]

Very close to the bow. When I think about it, the first break was a metal "quick link" that failed in a capsize. This time it was a faulty knot. In both cases, I was trying to save time during set-up.

Time to go to the Capricorn system, which Jake Kohl showed me at Tradewinds (and which Wouter has previously posted on line <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />)

I would think the system will be stronger and simpler by eliminating all unnecessary loops and links. I'll try to post an illustration, unless Wouter beats me to it, ( hint).

btw- Patrick, there is no proof without pictures! <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

We broke a rudder blade going to C for the first time during Race 1. Stuffed the bow, bore off and heard a huge crack. Same puff (or very close to) the puff that pitchpoled Chuck and Mavis. We didn't pitchpole but came to an abrupt halt long enough to see both Chuck and Mavis with the boat and working their way onto the hull. At that point we were close enough to see Matt/Gina and Seth/Stefan round C mark. We rounded C mark, but obviously had helm problems the rest of the race (the starboard rudder was flexing back and forth) and quickly lost contact with the lead boats. We were able to finish Race 1 in third place and start Race 2. We made the first triangle of race 2 (again, not competitive due to helm problems on port tack) and almost all the way back to A when the pressure from the broken starboard rudder popped the port rudder stock off the top pintle. We made our way back to the beach and scavenged a replacement rudder blade from Matt. We did notice the port rudder stock had a small crack on the lower portion (where the lower gudgeon pin goes in). We hoped it was only a surface crack.....

Sunday was rainy and blustery. We loaded the rudders back on, rigged the sails and got in line to get off the beach. It was downwind to the start so we put the spin up as we were a little late getting off the beach. As soon as the spin filled and loads were put on the rudders - BOOM, the whole port rudder casting exploded off the boat. The lower part of the rudder stock was ripped from the lower gudgeon pin. I guess it was not a “surface crack”. Done for the day/weekend.

We sailed the boat back to the beach using the tiller arm on the leeside for steerage. That was fun in the breeze. Loaded the boat on the trailer and headed home.

It was nice to see everyone and get some 80 degree sunshine, wish we could have participated in more of the racing.

Engineering questions:
1. Is it plausible that the broken starboard rudder caused the rudder stock problems on the port side (rudder stock popped of the top gudgeon pin and eventually complete rudder stock failure)?
2. We looked at the starboard gudgeons and they looked to be slightly misaligned (not much), but enough to distinguish with the naked eye. Would rudder not exactly in the vertical plane or not matching the port rudder’s plane be more apt to break? I’ll take some pictures and post them when I can.

I’d like to find out the root cause as to breaking the starboard rudder, as this is the second one that I have broken. Being the starboard rudder could be coincidence as both happened sailing downwind under spin on port tack in heavy wind.

It is entirely possible that my “technique” for bearing off was/is a little too radical and not as smooth as it should be. Heck, I was just trying to avoid an ender.

Sounds like something funny's going on with those rudders. Where are they breaking? And did they both go in the same way?

Sailing with one broken rudder would mean putting more load on the other rudder in order to get the same movement, but even so, I'd expect to have to seriously abuse a rudder to get it to break (short of hitting something, obviously).

Have you checked the rudder rake? If you've got them raked way forward under the boat, that might explain something. Someone on this forum talked of forward rake causing breakages (Rolf, was it you?), but I would have thought you'd have to use ridiculous rake for this to happen.

Paul

Tom Korz and I had a great time sailing down there, (f18 Tiger U-204) we were a little rusty but got smoother as the weekend progressed, unfortunatly so did everybody else. sat we had spin halyard problems, I replaced the block on the mast bail cause the old one was almost worn through, but the new block was too light and loaded up every time I had to raise the spin. Took a two handed pull standing up every pull to get the spin up! very tiring and slow, lost a lot of ground at the hoist every time. I learned a lot though and my crew is in for it this year. (I usually drive and I crewed for tom on my boat for this regatta) I have a lot more respect for crew now!

The breaks were internal right at the hole for the raising/lowering point (hole drilled through with a line going through it) and right under the bottom of the rudder stock. No "real" outward facing damage until we sailed with it for an hour or so and the head split at the seam. The rudders continue to evolve in their construction method. I guess there is no "Tom proof" carbon rudder yet. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Not passing judgement on any parts, but I need to know if I have a setup problem that I can correct. When I get everything back together, I will post pics of rudder rake, alignment, et al. Until then, we can only guess at the underlying issues.

Good to see you guys down there. We set up right next to you guys on Friday. It is always good to get a new perspective. <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

Hope the trip back was uneventful.

trip back was mostly eneventfull, till we got 20 miles from home then fog/rain/ice/snow. oh yea got that monster motorhome stuck in steve's front yard, eventually got it out and I made it home. Thanks for the help when I changed out that block on the mast.

oh yea, on our site www.204underground.com there is some pics of people and boats from tradwinds. check and see you might be in some.

That is a purely US modification. Aussies and EU sailors just sail with the rod system.

Wouter

I'm certainly not an expert in blade construction, but is that hole sealed in any way? If not, would it not let water into the core of the rudder, causing it to be come soft? That point in the rudder is going to be under serious load.

Paul

Wouter,

Can you (or anyone in the know) elaborate on this rod system in use elsewhere but not in the US?

Good to know about a possible design/construction issue now, the Blade's at the top of our short-list of boats to buy. Better to know how to avoid the problem altogether.

The US builder received a set up rod kickup rudders that were seriously below par. I guess this spooked them. Anyway something caused them to redesign the rudder setup using lines and kick-up cleats. It may also have been the seaweed floating around florida.

Currently both AHPC and Catamaranparts are producing rod system kick-up rudders that pass the "properly done" test. There are some builders out there that make similar rudder systems but the first one we tried delivered us crap work. And this is really an achievement as the rod is so incredibally simple that you have to make an effort to %^*&$* it up.


All the parts used in the rudders are shown in the picture below, there are no more parts, no spring, bungees or lines. There is just a one piece rudder stock the rudderblade and the rod with it locking pin a locking plate.




For more info on the rod system look here.

http://www.ahpc.com.au/pdf/Using%20Smart%20Lk%20Snap%20System.pdf

And yes it is truly a kick-up system and it works really well too. And, no, it is not a Hobie setup so , yes, you'll have to give yourself a little bit of time to figure out how to operate it. Once you do however you'll not want to go back to any nacra or hobie system. Biggest advantage, almost no moving parts. Dirt or salt doesn't bother it and once tuned and taped up they keep their settings for years and years.

Pretty much the rod is a more or less flexibly glass rod with black heat shrink around it. The heat shrink is there you won't get any splinters in your hands. The metal ending near the rearbeam has a pin in it that falls into a hole in a stainless steel plate fitted to the tiller. This happens when the rudder is down. For the rudder to move up it needs to press the pin out of it locking hole. As the pin is straight it can't do that UNLESS the rod itself is bending giving the pin the angle of the vertical as well. So with enough force the rod bend a little allowing the pin to pop out of its locking hole, the rod is then unsupported and the rudder moves up further.

On my stocks I tighten the bolts a little so the rudder just jams a little inside the stock now I can disengage the rods and sail through to surf with the rudders down and full control. As soon as the tips hit the bottom the rudders are pushed up. Only a little bit of contact is needed for that. When the surf is a shallow as 0.5 mtr the breakers are behind me. I've been doing this for 3 years now and everything is fine. Only now you can see that a little gelcoat is rubbed off the very ends ot the rudderboards.

If you really want to know all the details then Skype me sometime.

Or contact Tim Bohan, I used him my setup when he was over here at my place, he'll tell you what he saw and that it was good.

Before I forget the carbon rudder stocks of AHPC look much nicer then the ones show in the PDF document (old alu setup).

Wouter

The European Blades from Catamaranparts (imported from VWM) come with rudders and stock made by Catamaranparts. It's a simple but effective system. Stocks are made from aluminium.

I think the rods are basically similar to at least one version of the US Blades. A rod on the top of the rudder has a pin which pushes into a hole on the top of the rudder arm. This hold the rudder down, but if the rudder hits something solid, the rod should bend and the pin pop out.

What's different is that the geometry of the blades, stocks and rods is such that the blades can rotate through more than 180 degrees. When you want to raise the rudders, you take the rod out of the rudder arm, pull forward to raise the rudder then push back and down to cause the rudder to flip upwards, until it is resting facing slightly forward. See http://www.formula16.org/component/optio...ageViewsIndex=1

This gets the rudders completely clear of the water. Most similar systems only pull the rudders up to the horizontal, and then reattached the rod to the rudder arm using a different hole and a clip.

I have the above system on my Blade and have no complaints. There's very little to go wrong. The only disadvantage I've found is that the blades are fairly easy to knock down whilst you're rigging the boat. On the other hand, you don't trip over them, and they don't get blown to the side when you're pushing your boat around on the land, as the would if the rudders were horizontal.

When it comes to simple-but-effective systems, I'm also a fan of the dagger rudders on the Stealths. Very easy to get up and down, and they allow you to have the rudders half-down for shallow water and still be effective.

Paul

here we go

The AHPC version (building of Taipans Capricorns)


UP !




And down





And here the catamaran parts version :

When up




Sorry I haven't a picture of it in down position, but the concept is identical the AHPC setup the only difference is that the stock is made out of bend square alu tubing and that the rudder can rotate upwards beyond 180 degrees and be clear of shins and damage. If you turn the axle bolt a little tighter then if will stay up very well.


Both setups weight just under 1.50 kg per side. Together with the crossbar and tiller extension these systems weight (in my case) 3.078 kg or just under 7 lbs. I've abused them pretty hard and they are still going strong. I did have to glue an extra layer of carbon to one stock after I had been pushed back by a big breaking wave when leaving the beach and jammed my rudder between a sandbar and the hull, while the boat moved backwards. There must have been some force on the rudder then. Funny enough I only added this local reinforcement a year after the accident happened as I was lazy but eventually figured that that spot would turn into a weak spot as the fibres were bend a little and delaminating. The other stock and all the rest of the first one is just as I got them.

Another great feature are the red snap-on connector for the crossbar (and also tiller extension). No fiddling with retaining pins or clips. And the rudders remain straight when sailing under a spi and laying down the tiller for a while.

Personally I don't want any other system anymore. Quite a few A-cats and all the Capricorns have these setups as well.

Wouter

I believe that the additional holes for the "line based" raising/lowering system may be the culprit. There are actually two more holes in the rudder blade in that system rather than with the "rod" system. One hole drilled for the stopper knot and one hole drilled 90 degrees to that so that the line can be fed out of the rudder, up the stock and to the jam cleat. These holes are located just below the bottom of the rudder stock - where the loads would be quite high. I believe the newest rudder blades are solid core construction, instead of having some internal foam. My rudder blades were produced right after the US switch from "rods" to "lines", so they may not have been suited to that change.

BTW, Vectorworks as been great about sharing improvements and open to frank discussion about the product. I sincerely believe they are close to getting all the right pieces in place. My only problems have been the rudder blades and my problems may be more related to the timing of my boat delivery than anything else.

I once repaired a sheared off A-cat daggerboard for a friend. He hit a large underwater rock on his first outing with the boat, and the daggerboard sheared off cleanly below the hull. When removing the pain and some glass for repair, it became evident that the manufacturer had drilled and filled a 10mm hole at the leading edge. The shear started just at the hole, by design I suppose. Much better to break the board than cleaving the hull.
If you look at the bottom picture, you can just make out the hole at the leading edge in front of the light foam.

Wouter, I thought VWM (US Blades) are using the same rudders as in the pictures? Are they not from AHPC too? I thought the US buyers were doing the up-down string mods themselves. I liked your setup after I got used to it, I don't see the need to drill holes and add strings. Less is more to me. Dermot's Spitfire has a similar system and he added a small rubber bungie loop around the tiller bars to slip over the up-down rod after you set it in the down possition.

The only drawback to this system vs. a Hobie or Nacra type system is you must go down to the low side rudder to lift the rod/rudder unless you just want to run the rudder aground to have it kick up. It's not a big deal on a lake but if you are in the ocean, coming to shore with the wind behind you in surf, well, you don't want to go down to the low side to raise the rudder or you will risk a wipe out in the surf. In that case, I would just let it hit bottom and kick up...as long as the bottom is sand, not rocks! <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

The "strings" method is standard for the 2006 VMI Blades from what I can tell. No aftermarket changes. The 2005 boats may have had the rods, but they were not AHPC (they were Mackenzie, spelling?) and deemed inferior for some reason (not the rod system in general, but that particular rod system) as Wouter stated above.

The very first boats had a system we purchased that did not work very well.

We then began development of the rope sytem I am using now and personaly prefer for surf and weeds, but in reality it is whatever you get used to.

We have always offered a redesigned rod system, and for the last year that system is the one made by Catamaran parts that they install as standard for the boats we build for Europe.

If anyone wants to talk about it with me off line they are always welcome.

Matt

The McKenzies are were junk. It is the system I had. The rod would not bend, but the stainless steal screw did. WHAT A PAIN IN THE AAHOLE to replace that screw once bent. Also the rudder arms going to the stocks were underengineered. I must have done around two or three repairs already to each stock. The ones that came on my boat, were junk. I have done extensive modifications to my rudder system and today it is a much better setup.