Rudder lever-jack

[jdoorly]

I have been using a 1/8" line rove through a small hole in the aft edge of the rudder to pull it up and secure it up for trailering. But, on several occations the rudder has raised thirty or forty degrees while underway and if the troller motor is running the propeller can strike the rudder. A week ago this occured with the sails down in a skinny channel and the shear pin in the prop sheared. I had to anchor for an hour while I tried to figure out what happened and how to fix it. I was able to temporarily replace the shear pin with some of the broken pieces of shear pin.

I have a standard rudder and have found deploying the rudder has been a PITA! as I have to bend over transom and push hard on the top edge of the rudder to make it go down (not that I ever noticed a difference in performance whether it was up or down). So I was in the mood to do something about the rudder problems.

I thought about using auto-release clam-cleats; a good idea but much more expensive then my final design. I decided I wanted a lever that would mimic the rudder and indicate whether the rudder was up or down or how far down. I also wanted to be able to lock it down if I became frustrated with water pushing it up, and also have the option of using shock cord to hold it down. And, some way of easily locking the rudder up for trailering. So...
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There is a small screw just above the axle/bolt in the lever that can catch the lever and hold the rudder up. When the rudder is deployed the triangular section points down and if you force the lever further the geometry of the triangle will continue to move clockwise and lock the rudder down. It is working so well I haven't added the shock cord yet.
Oh, I can still raise the tiller and grab a cold one from the cooler I keep under it. I got the 1/8"x1"x36" aluminum bar at True Value for $8.00 and the 5 1/4-20 ss bolts and 2 screws out of my stash. The dimensions are important but I forgot 'em, ask me and I'll measure them.

[hectoretc]

This is a very slick design. If you wouldn't mind posting the dimensions, I'd like to put one together over the winter and have it ready for next spring.

Thanks, Scott

[jdoorly]

Hey Scott, here's the numbers:
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The link between the handle and the triangle can be any length, just don't instal the screw through the handle into the tiller until that link is installed. The triangle started out equalateral but I didn't need that much power to pull up the rudder so I cut the the one triangle link in half so the whole deal takes up less space. The length of the link to the rudder doesn't matter either and kinda depends on where you drill the hole.

I promised you pics of the companionway hatch so here's that...
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[Scott Mulford]

Ingenious.

The rudder is a pita. Never goes in easily but pops out when you turn your back. The release clip only holds when you are trying to take the rudder off.

You should make your lever system in wood and get rich.

[algonquin]

Great design with a lot of ingenuity. Of course there is a lot of that on your vessel. I plan to add your lever to my DSI this winter. A couple questions though.

Does the lever still allow the rudder to kick up if you hit an obstruction ??

Do you feel that the tiller may be weakend from the bolt attaching the lever to it ?? Brad

[jdoorly]

Scott M- I thought about using wood but it would take up a lot more space. I just bought 1/16" x 1" x 36" basswood at the hobby store to make a model of a boat I designed, and after your post it occurred to me I could just add 1/8" x 1" strips to the side of the aluminum, stain and varnish and good to go! Thanks.

Due to the interest in this I took a new and critical look at this design and found a couple faults. 1, although the handle does actually 'lock' and won't move at all past the rudder down position, the rudder can still drift upward up to 30 degrees due to water pushing on it as seen in photo #4...
Photo #1 rudder jack up
Photo #2 rudder jack down
Photo #3 rudder jack locked down
Photo #4 rudder jack locked but rudder up 30 degrees

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I'll probably screw a block of wood to the rudder head to prevent the apex of the triangle from moving past the 'locked' position.

2, The other thing is the rudder attachment. It's clunky and being below waterline it's parasitic. I'm thinkin the link should be moved from the side to the rear and the size reduced, but I don't have the final design yet.

3, The triangle should probably be moved closer to the centerline and possibly distributed to both sides of the rudder head to maximize stability and provide a centerline lead to the rudder attachment.

Algonquin- The rudder jack does not prevent the rudder from retreating due to impact when in the 'down' position. In the locked position, up and until I install a preventer, the rudder can swing back up to 30 degrees. There are several ways to attach shock cord, instead of using the 'locked' position, that will provide enough pressure to keep the rudder down yet allow it to give way when bonked. I'll try some of those ways and let you know what works best. The rudder seems strong enough, to me, to accept various kinds of attachments; no worries there!

So, I got few things think about and then get back to ya, what fun

[jdoorly]

Sorry Algonquin, I miss-read your question about the tiller.

My tiller was already weakened by a knot that fell out well before I got it. I filled the space with epoxy and continue to hope it remains in one piece. I have added 3 1/4" rods along the center line for the auto-helm attachment, and, I added some (screwed in) shims that take the lash out of the connection to the rudder head. These last 2 can be seen in the top view pic of tiller a few posts ago.

So the #8 x 1" wood screw that the handle pivots on is the least of my worries here. However, it does get a peak in shear force when the jack goes from down to lock. So, options are to not use the lock feature and/or use shock cord to 'lock' it down. And/or, change the triangle's links from 6.5" to 6.25" long to reduce locking force. I like the last 2.

[jdoorly]

I finished modifiing my rudder-jack. The mods address the short comings of the previous jack: The 'locked' position no longer allows the rudder to move up due to water, or rock, pressure, the rudder blade connection has been streamlined and moved to the centerline, and the triangle has been strengthened and moved to the centerline, and the link between the triangle and the rudder blade link has been doubled up to prevent bending.

If you don't want a 'locked' position then install a block of wood on the back of the rudder head in the vicinity of where the triangle contacts the rudder head, 1/2 to 3/4" block should do it. The idea is to not let the lower triangle link and the lower link to get parallel.

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As with the previous design the link from triangle to rudder blade link is variable depending on the location of the blade link hole, and the link from handle to triangle is variable depending on the location of the handle along the tiller. However, I will give measurements for my installation and they have changed slightly from before. Also, as previously, the build begins with installing the blade link, then the triangle and the lower link, then the upper link. Install the handle to the upper link and then put the rig in 'up' mode to find the location for the handle pivot screw in the tiller.

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To install the blade link I checked for clearance in all positions, double checked clearance with bolts through the holes, then countersank the link into the rudder blade, and countersank the flat head 1/4-20x 1/2" bolts into the link. On the otherside I countersank "T" nuts so it's all streamlined. I bent the link so that although it is attached to one side of the blade the jack attachment in on centerline.

To find the bolt hole locations for the blade link: Hold a square against the after edge of the rudder blade and the the other edge against the bottom of the rudder head with the rudder in the down position and draw a horizontal line to the after edge of the blade. Move down the blade edge 9/16" and draw another horizontal line and mark it at 1 5/16" out, that's the top hole. Now measure from the original line down 3 1/16" and draw a line out to 3" that's the lower hole (you rudder may vary).

The links are 1/8" thick by 1" wide aluminum of various lengths. They are attached to each other by a 1/4" hole 1/2" in from the end of the link so for a hole to hole dimension of 6 5/8" the overall link should be 7 5/8". I rounded the ends using a belt sander but it's not required.

The blade link is (outside hole to outside hole) 6", with another hole in the center of the link.

The triangle is made of 4 links. 3 are 6 1/2" (hth) and 1 is 3 1/4". Make a triangle with two 6 1/2's and the 3 1/4", use the other 6 1/2" link on the other side of the tiller bolts, and connect to the apex of the triangle. I bent the ends a little so fender washers and links stay parallel.

Measure the distance between the blade link hole and the triangle apex hole for the lower link. Mine was 15 1/8".

Mark where you want the handle on the tiller (in the rudder down position). Measure from there to the triangle's top of the short link for the upper link length. Mine was 10 13/16".

The handle doesn't need a hole in the, but it needs one on one end for the pivot and another in the middle for the upper link. Mine is 12 3/4" overall with the middle hole 6 1/4 from the end hole.

Hook it all up, put it in rudder up and mark where the end hole in the handle is and install the pivot.

Reference the last pic: I used a big rat tail file to remove some material (fiberglass) from the back of the rudder head just above the blades' slot. If you want a locking rudder you may have to make a channel there, but wait till the end to evaluate it. You don't need the clearance for the rudder up position, just for the rudder locked position. You may find it prevents attaining the locked position and you may think that is a good thing. But, what I do to attain the down position (for shallow water) is to push the jack handle all the way to locked and then tap the handle from the back.

BTW It's a lot of fun banging metal with a hammer, you should try it! And one last thing the foam sanding blocks work great for shinning up aluminum and stainless, even spent ones.

[hectoretc]

jdoorly - I'm serious, you really need to open an online store. You could build and sell your upgrades assembled or in kits as well as selling plans will full scale blueprints or patterns.

[jdoorly]

Thanks Scott, but If I make money I loose my disability checks, and I like to eat!

Oh, I forgot to say: Use nylox (stop nuts with nylon inside) nuts and tighten the joints till firm then back-off 1/2 turn. Don't forget the screw to hold the handle down.

[hectoretc]

That's OK with me... I'm happy to have continued free access to your ideas and designs.

[jdoorly]

I forgot to show this pic above...
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It shows the change to strengthen and put on centerline the triangle.