I need a better catch for kick up rudders

[Dave_S]

I broke two of the sacrificial timber straps that hold the rudders down on the weekend. There was a fair bit of wind around and confused swell and chop most about 1 to 1.5m but a few sets came through a bit bigger and the timber straps broke not from impact with something but just crashing in the water. Luckily one broke on the way there and one on the way back, not both at once.

The problem is in that chop, I have next to no chance of staying aboard while replacing one so I hope someone has a cleaver mechanical push back reset system they would recommend.

I'm thinking of a spring and ball bearing each side of the rudder case going into a detent or an over centre spring catch - it might be a bit bulky but do a better job.

[Dave_S]

Oh Oh Oh ....... had another thought, what about a spring to return the rudder to the down position - set and forget.

Problem solved.............. as you were

[Simi 60]

What about a thicker bit of timber or glassed ply so it still breaks on kickup but not from everyday use.

[RaymondR]

Gas spring.

[Simi 60]

Originally Posted by Simi 60

What about a thicker bit of timber or glassed ply so it still breaks on kickup but not from everyday use.

Its what's worked on countless other cats and tris before.
When you get the right strength knock up a dozen for next time.

[Dave_S]

Originally Posted by Simi 60

What about a thicker bit of timber or glassed ply so it still breaks on kickup but not from everyday use.

My big concern from yesterday was if I broke both rudder straps at once in weather I'm in trouble. So I thought I needed something that I can quickly restore steering. Then thought why not have it auto reset with a spring but that seems too simple and I wonder why it wasn't like that in the first place. Probably not ideal if you land on a reef but what is. I could have it catch in the up position with a cord release.

Originally Posted by RaymondR

Gas spring.

Your right a compression spring could be put on a cam action and would be ideal but I don't think I will get it in without it getting in the way of the steps. I think I will be able to fit a torsion spring in under the step which might have to do.

Thanks all

[Dave_S]

Ps What would happen tacking into 25kn with both dagger boards down full, 2 reefs and about 90% jib if we suddenly lost steering ?

[44'cruisingcat]

You'd probably go into irons.

[mark_morwood]

Originally Posted by Dave_S

Ps What would happen tacking into 25kn with both dagger boards down full, 2 reefs and about 90% jib if we suddenly lost steering ?

As has already been suggested you'd probably go into irons or maybe start fore-reaching depending on the boat. But if not you'd suddenly be learning how to steer off the wind by adjusting the balance of the jib, main and dagger boards.

As a separate question, why would you have both boards down full in 25kts of wind? On our Catana by then, depending on sea-state, we'd be doing 10 or more knots, with 1/2 or less of one or both boards down. Certainly on a Catana the manufacturer recommends you not have full boards down at that speed, you don't need them, and you are loading them very highly leading to an increased chance of breaking them.

In any case, you might want to just reach out to Schionning and ask for their advice?

Mark.

[valhalla360]

Look at the Gemini Catamaran system.

The rudders are held down with a rope and pulley system with the ends of the ropes held snug (BUT NOT TIGHT) with cam cleats.

If you hit something or the forces simply get too much in high speeds, they flip up overcoming the friction on the rope. Just release the cleat and pull the other rope (usually you have to at least slow down), reset the cleat and you are on your way...just takes a few seconds.

Even if you over tighten the cam cleats, if you use proper size ropes, the rope will break before the rudder. Now you have to dig into the lazzette but only happened once in the 10yrs we owned ours and it only impacted one rudder, so no major handling issues.

[Dave_S]

Originally Posted by 44'cruisingcat

You'd probably go into irons.

That's a lot better than I was thinking.

Originally Posted by mark_morwood

As a separate question, why would you have both boards down full in 25kts of wind? On our Catana by then, depending on sea-state, we'd be doing 10 or more knots, with 1/2 or less of one or both boards down. Certainly on a Catana the manufacturer recommends you not have full boards down at that speed, you don't need them, and you are loading them very highly leading to an increased chance of breaking them.

In any case, you might want to just reach out to Schionning and ask for their advice?

Mark.

Yesterday after breaking one rudder I decided to motor with both engines in case the other rudder came up so I would still have control.

I would have both down if trying to pinch tight up wind. It has never occurred to me to do anything else. Thanks, I'll talk to Schionning.

Originally Posted by valhalla360

Look at the Gemini Catamaran system.

The rudders are held down with a rope and pulley system with the ends of the ropes held snug (BUT NOT TIGHT) with cam cleats.

If you hit something or the forces simply get too much in high speeds, they flip up overcoming the friction on the rope. Just release the cleat and pull the other rope (usually you have to at least slow down), reset the cleat and you are on your way...just takes a few seconds.

Even if you over tighten the cam cleats, if you use proper size ropes, the rope will break before the rudder. Now you have to dig into the lazzette but only happened once in the 10yrs we owned ours and it only impacted one rudder, so no major handling issues.

Sounds interesting, I'll have a look. Thanks.

[senormechanico]

My Dragonfly has clam cleats for the rudder and centerboard which will disconnect under load. There's a spring loaded lever with a ball to reset them.

[LeeV]

On my Condor 40 we finally drilled through the cassette and Rudder (pre-drilled large, filled with thickened epoxy, re-drilled smaller hole and used thin fiberglass rod as a breakaway. It was only 4" longer than the total width, and I heated both ends to bend a small amount to keep it from sliding out. Sorry I don't have pics, but it worked. Our biggest obstacles were the crab traps in the Chesapeake when at speed (esp at night). We'd carry a dozen on board at a time!

[RaymondR]

Originally Posted by Dave_S

My big concern from yesterday was if I broke both rudder straps at once in weather I'm in trouble. So I thought I needed something that I can quickly restore steering. Then thought why not have it auto reset with a spring but that seems too simple and I wonder why it wasn't like that in the first place. Probably not ideal if you land on a reef but what is. I could have it catch in the up position with a cord release.



Your right a compression spring could be put on a cam action and would be ideal but I don't think I will get it in without it getting in the way of the steps. I think I will be able to fit a torsion spring in under the step which might have to do.

Thanks all

You could use hydraulics on the back side of the gas spring piston to lift the rudders from the steering position with a hand pump.

More complicated than the rope and cleat but more utility.

[catsketcher]

IIRC Schionning cassettes are not trapezoid but rectangular. Most cases are rectangular prisms but I like building them slightly trapezoidal so that they don't slop around at all. It makes them a little more docile.

I had the same problem you have. In the end I found some plastic hose that will hold on well but will break/pull through when needed. You should be able to beef up the hold downs you have now - they should not break from sailing loads so experiment some more and when you are happy make a heap of them.

A friend with a Wilderness near your size made timber pieces that had cuts above the edges of the cassette case. This allowed the piece to snap cleanly where it needed to rather than in the middle which then gummed up the system.

If you want to you can do what has been advised above. You could try rope hold downs with a small fuse line attached. The cord is attached to the end of the line to a saddle which then goes over the cassette and back down to another pulley - so you get a 2;1. If the fuse breaks the rudder pops up but you have a stopper on the line so that it cannot pull through the fairlead on the cassette. You can pull the rope back on and this time it is 1;1 and this will get you home.

Or you can use something like the cleat shown which can trip. I am pretty sure Schionning says to drill a jamb cleat to allow the rope to pull through under high load.

A little bit of fiddling and you should not have them popping up when not needed.