Kickup Rudder

[Dan Cavins]

Hi guys. I sense there is an easy answer but I don't know what it is. I have a 23', 2000lbs. sailboat, NIS-23. It is made for thin water use and I want a rudder that will give up before other important parts if we catch something. It's on a pivot in a rudder box. What mechanism to hold it down but release if need be? A type of cleat with line, would shock cord work in some fashion, a shear bolt? Would appreciate your experience. Thanks, Dan.

[almeyer]

Dan,
Over the holidays I modified my kickup rudder to incorporate a downhaul line to hold the blade in the down position. Other than trying the system out while the boat is mounted on the trailer, it hasn't been proof-tested yet, but I think it will work.
Al

Rudder modification (http://www.imagestation.com/album/pictures.html?id=2115026217)

[JimD]

And check out Brian's post from Misc.Boat Related from yesterday on this releasing cleat:

http://www.woodenboat-ubb.com/ubb/ultimatebb.php?ubb=get_topic;f=6;t=005388

[ahp]

I have an O'Day DaySailor made out of that other stuff. The rudder blade, not the whole rudder assembly, is pivoted to swing up if it stikes something. The blade is weighted to normally stay down, and if does stike it swings back down again afterward with no help from lanyards, shock cords or anything else. Simple and it works.

[almeyer]

The blade is weighted to normally stay down, and if does stike it swings back down again afterward with no help from lanyards, shock cords or anything else. Simple and it works.
--------------------------------------------------------------------------------
Just my opinion, but that's definately the best way to go, if the geometry of the rudder assembly will allow it. On my boat, with a raked transom and the pivot point on the rudder blade located relatively far back, the rudder blade would hang vertical (below the pivot pin) rather than up parallel to the transom. Hence the downhaul.
I like the springback cleat shown on the Duckworks site; it looks like it would work well in this application. But I didn't like the look of it on my boat, which shows a traditional influence. Granted, that's an absolutely subjective, irrational reason not to use the springback cleat.
Al

[Karl A. Hilbert]

Sorry missed JimD's about the other thread. Deleted my post

[ 01-08-2006, 05:47 PM: Message edited by: Karl A. Hilbert ]

[Steve Lansdowne]

Al, I'm not familiar with the knot you mention, but unless it's a breakaway of some type it seems to me that you're just keeping the rudder downhauled all the time by using a rope. Why not incorporate some shock cord in there somewhere to allow some "give" when you hit something?

[almeyer]

You're right, Steve, the system I've got set up will keep the rudder blade in the down position. It's easy to loosen the line at the jam cleat and allow the blade to pivot, but it's not automatic. So if I'm coming in to shore, I can loosen the line ahead of time and allow the blade to float. But if I hit a submerged obstruction I don't know about, I could be in trouble. The system I've got is fairly simple, but as you point out, I may need to tweak it a bit.
Al

[Dan Cavins]

Thanks guys. That release clamp looks like the ticket, I ordered one this morning. I like the weighting idea except that I'm actually trying to lighten the thing with this rebuild. And I understand the non traditional look of it but I am bowing to function here. We'll see how it goes, thanks again, Dan.

[John Meachen]

I have been a fan of the clamcleat CL257 for quite a while.There are a couple of things that I think are important if you use a rope downhaul.First,the point of contact between the rope and the rudder blade should be tangential to any radius of the rudder to keep the load square,for maximum efficiency.Second,I think it is important to minimise friction caused by going around sharp corners as the friction may try to hold down the rudder when you would prefer the cleat to release it.If you make the rudder stock with this in mind,it is not too hard to leave a groove through to the underside of the tiller port and to make a mortise for a sheave to fit into.A small moulding plane will leave a groove for the rudder downhaul to run through on its way to the cleat.All things being equal,I like to position the cleat on the underside of the tiller so that the line needs a positive effort to be cleated,gravity tending to help in this respect.When I get round to keeping this year's new year resolution,which is to learn to post images on this forum,I'll try to post a sketch as it would probably be clearer than this explanation.

[Gallus102]

We have to launch & recover our boat in very shallow water, so a kick-up rudder lift system is important. Most of the boats at our club have an arrangement where the rudder is held down by shock-cord and lifted by a 2:1 tackle. The lifting pennant is led along the tiller and secured with a Lance-Cleat (from RWO). The rudder is normally vertical (the tip is resting on the driveway in these pictures).

http://www.imagestation.com/picture/sraid199/pb39e7aedcbf526f1b437f463921622f7/f0a3bc78.jpg

I used a solid elastomer strech cord on my rudder and the bearing sheaves are from Harken. The cord is continuous through the rudder head so tension can be equalized on both sides. The elastomer has enough "pull" so the rudder does not move up even at higher planing speeds.

The lifting block is secured to the rudder with a strap fork and clevis pin. The white UHDM half-moon gives a little better initial lifting angle on the rudder blade and keeps the rigging clear of the rudder head.

http://www.imagestation.com/picture/sraid199/pef6ce3c10ac83751acdfbf397db3339f/f0a3bc77.jpg

I am currently building a mahogany version of the rudder head (still using aluminum plate for rudder blade; class rules). It will follow the same design, but with yellow elastomer to contrast with the bright finish on the rudder head.

I've used this arrangement for two seasons and it works very well in practice. Besides the shallow water flexibility, I use it frequently to clear weeds from the rudder. There are also times when I need to scull, and a horizontal rudder blade is instantly available. Just let off on the lifting pennat and the rudder returns to vertical.

[Pateplumaboat]

Just completed a kick-up rudder on my Amberjack Dory.

I hope this will work as planned. Still needs cleats on tiller to fix/block downhaul (yellow) and uphaul (blue) lines.

More pictures on links below

http://lh6.ggpht.com/_yaEpx5u2uyA/TShHbExdE5I/AAAAAAAAC58/dYSGShedWQY/s640/DSC03610.JPG


http://lh6.ggpht.com/_yaEpx5u2uyA/TShHby36q3I/AAAAAAAAC6E/5qd_kBpnWqE/s640/DSC03623.JPG


Regards from Austria

[Vinny&Shawn]

Townclass sloops which are native to Newburyport Mass. are 16'6" 800#, they have a good kick up system. The swing part is held in a mortise and pivotson a single bolt. It is weighted with a lead ballast and works very well. We owned one for 3 years and sailed it in a tidal area of Maine. It was great for going into small and shallow areas.
Here are some pictures of our prior Towny and the new owner has added a real nice touch for power!!

http://i419.photobucket.com/albums/pp278/vgeorge1/016.jpg?t=1294530585http://i419.photobucket.com/albums/pp278/vgeorge1/014.jpg?t=1294530695http://i419.photobucket.com/albums/pp278/vgeorge1/013.jpg?t=1294530760

[hikingchrs]

On my Caledoina Yawl the rudder floats in 2 positions, 1. kicked up 2. "down", the rudder bladevfloats forward against the forward part of the rudder head, the piviot bolt tension adjusts how much force is required to trip. the only trouble with this system is that it does not reset automaticly, need to push the rudder back down after it trips.

[almot09]

A type of cleat with line, would shock cord work in some fashion, a shear bolt?
Can't say about shear bolt.
Yes, cleat with line and yes, shock cord. Use both! Shock cord as a blade downhaul line and a cleat or barrel lock near cockpit to adjust the tension of that cord (or release it completely when you are about to lift the rudder).

[Rational Root]

Try these...
http://davesboat.blogspot.com/2010/12/auto-release-cleat-angles.html
http://davesboat.blogspot.com/2010/11/kick-up-rudder.html

If the tiller tilts up, put the cleat on the rudder, or it will pop every time you lift the tiller.

Duckworks have the auto release cleats.

[Thorne]

My old SJ21 had a kickup rudder held down by heavy shock cord, worked very well. No photos of the system but I imagine it is very similar to other lightweight 20-22' boat systems.

[ARW123]

I recently devised the following for my gun punt:-

http://farm3.static.flickr.com/2049/5801189602_1f1aff0e0b_b.jpg

The above is 2/3 of the laminations of the rudder stock sandwich.The rudder sits inbetween the sadwich and the free end of the shock-chord is attached to the leading top edge.

The stock when comppleted would look like this:

http://farm4.static.flickr.com/3475/5801201906_670c6fff60_b.jpg

and works likethis (before final cheek of stock is glued in place, so you can see the mechanism work):


http://www.youtube.com/watch?v=1UFV59nD7XY