Index

Keep the Rudder Blade Locked Down and on the Transom.

INDEX - Pintle lock, Blade lock, Construction, Operation, Prop Damage, Moored.

2004 - After fours years of use with my block and tackle blade pull down system the blade has some unexpected wear around the pivot hole and in the pull up bolt hole where the T-bolt rests.  So I've developed a more robust solution for both and updated the text and diagrams as per below.  The rudder has experienced no fatigue since then.  _________________________________________________________________________________________________________________

There are two rudder versions for the SJ23, fixed and kick up.  The fixed version is for sailing in deep water where you seldom or never expect the bottom to come up to 'touch' the hull.  The kick up version is for sailing in shallow water where the "bottom may occasionally come up to touch" the hull.  The kick up version has the additional safety advantage of protecting the blade and the transom in the event of an accidental grounding.  This same safety feature also allows the party animals to hit the beach by allowing the sandy bottom to push the blade up.  Notice I said sand, NOT ROCKS! I don't know about anybody else, but I've never been able to lift the blade by hand as I approach the beach.  I find the reach into the murky depths just a wee bit beyond my hands! 

The factory designed kick up rudder (shown below left) incorporates several loops of heavy duty bungee cord at the leading edge of the blade hinge.  The purpose of the bungee cord is to hold the blade down for normal sailing and allow the blade to be kicked up in the event of a grounding.  The bungee cords are looped between two holes at the leading edge of the rudder hinges; a 1" hole through the top of the blade and a 1/2" hole through the bottom of the rudder head.  This was the configuration when I bought Panache.  For assured performance, the bungee cord must be replaced annually.  What a pain for a  system that doesn't work well! 

There are several drawbacks to the bungee cord system;

1. The blade lifts (pivots aft) with boat speed.  The faster Panache sailed, the more the blade lifted.  Sometimes the blade lifted so far that when the tiller was relaxed, the blade popped to the surface.  Again, what a pain.  A trailing blade creates heavy, sloppy steering that loads up the rudder head with incredible forces.  Something will eventually break.  I once had a bunch of novices on board when this was downright dangerous.  So much for a relaxing Sunday afternoon of sailing. Not exactly the situation you want when the wind is blowing!
2. At hull speed the loops of bungee cord create a rooster tail that soaks the cockpit crew with a very fine mist in a following breeze.  Nice on a hot day but miserable on a cool day.  They also generate a loud burbling sound that is difficult to talk over. 
3. Pushing off a beach or backing up in shallow water is difficult if not impossible with the bungee cord driving the blade into the bottom.  It's especially grating to hear the blade on gravel or rocks!  You are forced to lift the blade by hand or to remove the rudder from the transom.  In either case, I'll guarantee that the winds will push the boat back to the beach before you can reattaching the rudder.  Isn't this where you just came from?  You get the picture don't you?  This system just doesn't work and that's putting it nicely. 

If you have a fixed rudder, you only have to consider locking the pintle.

1 - PINTLE LOCK - The factory stainless steel lock down spring is not particularly strong and is woefully inadequate for the job.  Quite frankly I think this technique belongs on a dinghy, not on a pocket cruiser.  The sooner you replace this spring, the sooner you will have a safer boat.  Consider Frank's experience.  "I was sailing pretty much at hull speed in 2' to 3' high waves with wind at about 20 knots and gusting higher when the rudder came off the transom, held only by my hand on the tiller and the Tiller Tamer line!  We immediately lost steerage, both sails luffing like mad in the wind, the boat bouncing crazily in the waves, leading to an unintended jibe while I tried to reinsert the pintles in the gudgeons.  Under these conditions the water pressure on the rudder makes this a monumental task, but we eventually succeeded and got underway again.  The force on the rudder during this episode was great enough to bend the pintle to make reinstalling the rudder a challenge.  The 3/8" stainless steel pintle is too stiff to straighten with a vice grip on board the boat!  The total loss of rudder/steerage in strong winds/waves is a very unpleasant and possibly a dangerous situation."   Frank.

The point to note is that the rudder MAY pop out of the gudgeons through wave action when the boat is in a deep trough or the stern is lifted by a wave.  The reason is that the foam cored rudder floats and the small metal spring that is designed to lock the rudder to the transom isn't strong enough to keep it attached.  One solution is to install a short, strong bungee cord between the lower gudgeon and hook it to the hole in the upper pintle.  Replace the bungee cord annually as it will fatigue with exposure to UV light.  Another solution is to slip a hair pin or thick cotter pin through the hole in the upper pintle.  Secure the pin to the rudder with a short line so you don't loose it.  The pin MUST not come off on its own and you should be able to operate it without tools.  I use a 1/8" thick cotter pin on Panache.  The ends are slightly spread apart which is sufficient to keep it in the pintle.  Just squeeze them together to insert.

If a pintle bends, you can make a temporary one from a (4 x 3/8)" stainless steel bolt.  Taper the end to facilitate installation on the gudgeon.  Drill a small hole through the side of the bolt to accept a cotter or roll pin to secure it.  This requires using a titanium or cobalt drill bit, turning at slow speed with cutting oil or paste, to keep the metal cool.  Sharp matters!  Also, file a slight depression on the side of the bolt to start the drill.  Once the bolt is inserted in the rudder head, use marine sealant around the pin to prevent movement.  The lower pintle should be longer than the upper one to ease installing the rudder pintles in the gudgeons.  i.e...  insert the lower one first and the upper one second.  You'll appreciate this little bit of forethought when you have to install the rudder on the transom as Frank did. 

2 - BLADE LOCK - My first solution to locking the blade down was to replace the old worn bungee cord.  When that didn't work I added more loops of the same size cord.  That didn't work either.  Then I replaced it with heavy duty bungee cord.  Unfortunately it was so strong that I could no longer lift the blade manually but it could pivot up for beaching by letting the sand push it up.  Despite these "fixes" the blade still managed to lift gradually while underway resulting in heavy steering and loss of speed. 

1. A friend suggested installing a 1/4" wood dowel through both the rudder head and the blade, thereby locking the blade in the down position.  He used this technique and claims that the wood is soft enough that it will shear off clean against the aluminum rudder head without damaging the rudder blade.  Add a little moisture from the water and the wood breaks even easier!  He also suggested carrying spare dowels, just in case!  I didn't like this idea because I have too much shallow water to contend with.
2. I also considered the external control line solution shown at right.  A nice feature of this design is that the line can also hold the blade up for shallow water mooring or tight docking.  It should be noted that most SJ23 rudders cannot be tipped up this high.  To create the extra pivot room the owner shortened the wood spacer at the aft end of the rudder head.  I now moor Panache with the blade up and she behaves much more civil at the mooring.  Besides being easier on the rudder and fittings, the blade is also protected in the event of an accidental grounding.  Something always worth considering!  Another point to consider about the rudder blade is wear and delamination.  With the blade out of the water it can't wear out and it can't absorb water. 

So I designed the internal 4 to1 block and tackle system shown below right.  The free end of the line exists out the aft of the rudder head and is guided over the top where it lays over the tiller slot for ready use.  The system works like a charm, both to hold the blade down and to release it quickly to allow it to float at the surface. 

Another reason why I developed this system was to lift the blade while motoring in tight quarters to prevent the propeller from hitting the blade when it is turned far enough to starboard.  I have since installed a ring around the propeller to keep the rudder from touching it.  See Tech Tip D06.  The blade can be damaged from a myriad of other reasons so I'll let you use your imagination.  See Tech Tip B09. 

CONSTRUCTION - Referring to the diagram below right, the first step is to imbed a 3/8" stainless steel bolt into the top of the blade to hold the turning block.  The combination is effectively a T-bolt. 

1. Using the factory bungee hole in the blade as a target, drill a 3/8" diameter hole down the center of the blade, aiming for the center of the bungee hole.
2. An imbedded T-bolt is the perfect solution for anchoring the bolt.  Make the round nut from 3/4" OD rod or thick wall aluminum tubing.  Drill a hole across it, through both sides (center), and tap the holes to receive the NC thread of the 3/8" bolt.
3. Drill out the bungee hole to receive the 3/4" OD aluminum and gouge out 1/4" of exposed foam from the inside surface of the blade hole.  Fill the 1/4" depression with epoxy flush to the edge of the hole.  This creates compression strength between the two halves of the rudder blade and prevents water absorption into the foam. Sand the epoxy smooth.
4. You should now be able to insert the round nut into the blade hole aligning the threaded holes to receive the bolt. 
5. Slip a stainless bracket (to hold the small sheave for terminating the bottom end of the block and tackle) under the head of the 3/8" bolt and push the bolt into the rudder blade hole, screw it into the round nut you previously made. 
6. Seal the blade hole with Sikaflex for future disassembly. 
7. I used a couple of 1" ball bearing double blocks that were kicking around in the my boat storage stuff.  The top block is a surface mount style and screwed to the inside of the wood spacer at the back of the rudder head.  The bottom block is a 1" Harken double block.  I have no idea what the part numbers are.  The free end of the 1/4" control line exits through the wood spacer at the back and goes to a jam cleat mounted outside the rudder head.  Drill a 5/16" angled hole for the control line and sand the hole smooth to minimize line wear.  Leave the line long enough to conveniently dangle over the transom into the cockpit. 

You now have a 3x1 purchase that is strong enough to pull the blade down while sailing.  (To be a 4x1 purchase, the dead ended line should be attached to the bottom block).

HINT: If you coat the hinge end of the blade (portion that fits inside the rudder head) with epoxy saturated with carbon graphite powder it will create an extremely hard and slippery surface, making it easier to pivot the blade.  Mix the carbon graphite about 10% by volume.  It makes a very black soupy mess!  To complete the job, sand off any high spots and insert a bushing or stainless tube inside the pivot hole of the blade.  Cut the tube ever so slightly longer than the thickness of the blade.  This way you can tighten the pivot bolt and rudder head against the tube to eliminate side play without jamming the blade.  Shortly thereafter I coated the entire blade with epoxy saturated with carbon graphite.

OPERATION - The rudder is streamlined with the internal block and tackle and the system has sufficient mechanical advantage to pull the blade down, regardless of the side load on the blade due to hull speed or wind direction.  If you decide to scoot through shallow water to win the race, you can release the blade so it floats to the surface.  When you return to deep water there is enough mechanical advantage to pull the blade down, all without stopping the boat.  A word of caution about sailing with the blade up; the forces on the rudder head and tiller can be tremendous, especially when sailing upwind with a few waves that you have to steer for. 

CAUTION: With the block and tackle locking system described in this Tech Tip, you MUST be ready to release the locking line when approaching shallow water.  This is why it's so important to have an accessible and quick to release system.  Failure to release the blade could result in structural damage to the rudder blade and/or the transom if you hit the bottom too hard.  But then this would be no different than grounding with a fixed rudder. 

An improvement on locking the control line with a jam cleat is the Clamcleat® CL257 mini auto-releasing rope cleat.  The advantage of the CL257 is that it has an adjustable release load setting that gives peace of mind to the single handed sailor who is too busy looking after something else.  It never fails that fifty things happen at the same time! 

PS: For those of you who don't have a depth sounder, a fully lowered center board touches the bottom before the rudder!   Hmmm.
For those of you not wishing to go through all of this, you could build your own kick up rudder or buy one from Rudder Craft.  Very slick design.
 

I have yet to fabricate a pull up system.  The design criteria has to include the following:

• No noise while sailing.
• No drag in the water.
• Able to hold the blade up out of the water while at the mooring.
• System must be self contained on the rudder for quick ramp launching.

I know its a tall order but it can be done.  I'm open to ideas.
 

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