New rudder head

[TIM WEBB]

I was tired of having to remove the rudder from the boat when anchoring stern to shore, so I built a new rudder head for TRW. 1/8" aluminum plate, aluminum spacers, and stainless hardware. Pivot bolt slot allows blade to be in the normal low position when down, but completely out of the way when up. When downhaul is applied, lower forward bolt keeps blade from hyper-extending forward or sliding up in the slot. I had a second bolt where the empty hole is but it interfered with the rotation of the blade:



On the upper leading edge of the blade there is a small brass eye as a guide for the downhaul. Without it the DH line has a tendency to "wander" out from between the plates. Upper spacers are slightly shorter to accommodate the slot in the stock tiller. I'll be grinding off the protruding bolt ends.



Four nylon washers (one each inside and outside the plate on each side) help the bolt slide smoothly in the slot and help the blade rotate freely, while minimizing what I call "blade wobble". I also put a nylon shim inside the blade hole.



In use on boat, anchored stern to shore in a couple inches of water. Keel is resting on the sandy bottom, and the head/blade are not digging in. I'm using both a safety clip and tab on the upper pintle.



I based this design partly on what CCSB is supplying with new DS's, and partly on a design that jeadstx built. It sure proved itself on last weekend's FL 120! ;-P

[GreenLake]

Is the rudder pivot free to slide up in the slot, or does it have to be loosened first?

[TIM WEBB]

It has a nyloc nut that is snugged down just tight enough to prevent "wobble", but just loose enough to allow the pivot bolt to slide in the slot. Actually, when the blade is all the way up, the uphaul isn't really needed, as there is enough friction between the plates and blade to hold it up.

[jeadstx]

Finally get to see pictures of the rudder head. Must have worked well since the the Facebook FL120 site commented your boat was one of the fastest boats.

John

[GreenLake]

Interesting.

The main reason I have not fitted a downhaul is that unless it exits exactly at the tiller hinge, it prevents one from lifting the tiller. I often lift mine to get to the other side. Esp. when sailing with more than one crew (when space gets tight). (Releasing and re-tightening the downhaul is theoretically possible, but those moments tend to be the busiest).

Your chosen design with the two plates would allow that alternative routing, mine (using a solid rudder head) does not, or I would have to drill a channel. So far, tightening the rudder pivot so I can barely fold it by hand seems to be enough to keep the rudder down by friction.

Did you use a load-release cleat for your downhaul? Usually done for accidental groundings, but if you have one, Is that enough to release when you lift the tiller?

[TIM WEBB]

Finally get to see pictures of the rudder head. Must have worked well since the the Facebook FL120 site commented your boat was one of the fastest boats.

John

I told you I wasn't going to post pics of the new rudder head until I knew it was really done, and I didn't, but now it is, so now I have ;-P

Yes, it did work as designed at the 120, as shown in the last pic. As to whether I was the fastest boat or not, well, that's debatable. Yes, I happened to be the boat furthest east when that pic was taken, but I had also had somewhat of a head start, and was simply able to point better than the single-sail boats that day. On the next day's downwind run, I got horizon-jobbed by a Lightning flying only their spin (He'd skied his main halyard!). The 120 is not a race tho ...

[TIM WEBB]

Interesting.

The main reason I have not fitted a downhaul is that unless it exits exactly at the tiller hinge, it prevents one from lifting the tiller. I often lift mine to get to the other side. Esp. when sailing with more than one crew (when space gets tight). (Releasing and re-tightening the downhaul is theoretically possible, but those moments tend to be the busiest).

Your chosen design with the two plates would allow that alternative routing, mine (using a solid rudder head) does not, or I would have to drill a channel. So far, tightening the rudder pivot so I can barely fold it by hand seems to be enough to keep the rudder down by friction.

Did you use a load-release cleat for your downhaul? Usually done for accidental groundings, but if you have one, Is that enough to release when you lift the tiller?

I can't lift the tiller while sailing anyway because of the tiller tamer, but you are correct in that the DH would prevent same even w/o one. I pretty much only need to raise the tiller at anchor in order to set up the boom tent.

Yes, I have an autorelease clamcleat on the DH, as seen in a couple of the pics. I've had one on there for awhile even with the old rudder head. Have one on the CB DH as well. Yes, it will pop if I try to raise the tiller w/ the DH engaged, but by then I've usually pulled up the rudder head and disconnected the tiller tamer after anchoring to shore ...

[GreenLake]

My tiller tamer is a bungee. It has enough give to it that I can still raise the tiller a bit -- and every little bit helps.

However, I only use it when single-handing and then I sit forward of the tiller anyway. When sailing with crew (or passengers) being able to lift the tiller is more important. I once had enough people in the cockpit that the smallest one had to duck into the cuddy during tacks, so that the rest could switch sides. We had it down to just the right mix or weights on the two sides, you see, to balance the boat in the prevailing conditions...

I'm spoiled in that much, if not most of my sailing is to and from docks with deep enough water so that raising the rudder is something I do rarely.

BTW, I found tiny stress cracks where my rudder head holds the flanges for the pivot. The flanges are just 1/4" plywood, with a layer of glass for additional strength. I have no idea how strong they are relative to critical loads on the rudder, but suspect that the design isn't up to the kind of abuse that jeadstx reports from the Tx200. So yours would have the edge there.

(But mine floats ).

[jeadstx]

I am able to raise my tiller about 20 to 30 degrees with the DH attached without it coming out of the auto cleat. My tiller tamer is my main limiting factor.

John

[TIM WEBB]

I'm spoiled in that much, if not most of my sailing is to and from docks with deep enough water so that raising the rudder is something I do rarely.

Ah, lucky you! But even when in deep water, I always at least raise the blade for launch and retrieval. Dunno, just a habit I got into right from the get go ...

BTW, I found tiny stress cracks where my rudder head holds the flanges for the pivot. The flanges are just 1/4" plywood, with a layer of glass for additional strength. I have no idea how strong they are relative to critical loads on the rudder, but suspect that the design isn't up to the kind of abuse that jeadstx reports from the Tx200. So yours would have the edge there.

(But mine floats ).

Do you happen to have any pics of what you are describing? Is yours a stock rudder head? If not, I'm having trouble visualizing it ...

[TIM WEBB]

I am able to raise my tiller about 20 to 30 degrees with the DH attached without it coming out of the auto cleat. My tiller tamer is my main limiting factor.

John

Yeah, I think we now have pretty similar setups John.

[GreenLake]

Do you happen to have any pics of what you are describing? Is yours a stock rudder head? If not, I'm having trouble visualizing it ...

Here's a drawing. There's nothing from the original stock rudder retained, but it's been influenced by the stock design.



The bottom view is edge on. The relative thickness is not to scale. The blade and center of the head are 1" thick. The "cheeks" are, as I mentioned, 1/4" plywood with a layer of glass cloth epoxied to each side, turning them into a sort of sandwich material that should be a bit stronger than just the wood alone.

You will see in the middle, the hole for the pivot, to the right of it the 'gap' between rudder blade and head. The black line shows where the head is cut out a bit, as shown above. At the far right is the hole for the tiller pivot. The stress cracks are very small, and have formed in the corners of the "gap" where the cheeks meet the center piece of the rudder head. It's clear that something is flexing there as the rudder is loaded.

I just now laid the rudder on two supports (middle of blade and middle of head) and put my entire weight on the joint - did not see the cracks opening even.

[TIM WEBB]

Interesting design!

1. Does it keep the blade at the same depth as stock? Your drawing doesn't show pintle locations, and your pivot hole is 1" above the bottom of the head, but I can't tell where that is in relation to the waterline? My design has the blade about 5/8" higher than stock (when down). Didn't want to go any higher than that as the DS needs all the rudder in the water it can get! ;-P

2. What material is the center headpiece made of, and how are the flanges attached to it? Epoxied? With or w/o fasteners? One of the main differences between my design and John's is that he used a wood core for his, whereas I used spacers. Didn't want any wood or fiberglass involved at all ...

3. Are you using a stock tiller? A 1" wide headstock would seem to accommodate one just fine ... ?

I would imagine that if the cracks didn't open when under load in your test, that it may be possible that the cracks are not stress cracks, but rather from expansion/contraction or something like that?

[GreenLake]

Interesting design!

Simplicity itself. Getting the shape roughed out and assembled was really quick. More than half of the effort went into fairing and painting. Getting the pintles on was a bit fiddly, as they needed grooves chiseled for them.

1. Does it keep the blade at the same depth as stock? Your drawing doesn't show pintle locations, and your pivot hole is 1" above the bottom of the head, but I can't tell where that is in relation to the waterline? My design has the blade about 5/8" higher than stock (when down). Didn't want to go any higher than that as the DS needs all the rudder in the water it can get! ;-P

It's absolutely stock compatible, and that means class legal. Although it would be simple to change the dimensions (make the blade a bit longer, head a bit shorter) if that's what you wanted. My main concerns were to

1. get a better foil shape
2. get the head above the waterline
3. reduce weight

The pintle locations are such that the pivot is a the same place it was before. None of the hardware is shown.

The rudder has:

1. 1/2" SS carriage bolt with washer and wingnut
2. a nylon bushing for same
3. a HDPE wedge as a tiller stop in front of the neck
4. 2 pintles
5. a springy blade to prevent the pintles from slipping out of the gudgeons
6. and a 3/16" or thereabouts carriage bolt with washer and wingnut for the tiller
7. nylon bushing for same

2. What material is the center headpiece made of, and how are the flanges attached to it? Epoxied? With or w/o fasteners? One of the main differences between my design and John's is that he used a wood core for his, whereas I used spacers. Didn't want any wood or fiberglass involved at all ...

I started with a single board, laminated from 2 planks of .5" plywood. I then shaped the foil first (having a long flat part made that easier). Then I cut the outline of head and blade with a jigsaw. So, the head is made from the same material as the blade. The flanges, or cheeks are as described earlier and simply epoxied to the head. With that much area for the glue joint there seemed little point to using fasteners. (All I would do differently about the head would be to make the 'neck' a bit narrower in the back, because the tiller no longer folds all the way).

I know I added a sheath of fiberglass to the rudder blade. Normally wouldn't need that for the head, but I may have added one there, too, simply to keep the dimensions the same (so the blade would fit between the flanges). I also made a diagonal cut to slice off the front tip of the blade and glued it back on. That adds a glue line as defense against any water getting in from a grounding.

3. Are you using a stock tiller? A 1" wide headstock would seem to accommodate one just fine ... ?

that was the idea. For the blade, a slightly thicker stock would have allowed and even better profile, but I liked the .5" plywood because of how many plies it has. If you read my original post (or article in the DS) you will find that I used the pattern of "banding" revealed when shaping the blade as a depth guide for getting the rough shape.

I would imagine that if the cracks didn't open when under load in your test, that it may be possible that the cracks are not stress cracks, but rather from expansion/contraction or something like that?

At this point, I'm not sure that they extend beyond the paint.

[TIM WEBB]

OK, that's right, now I remember the post about using the banding to get the shape.

My main goals were to be able to use the stock tiller and blade, not introduce any more wood or fiberglass to the assembly, and get the rudder up and off the bottom when beached stern to shore. Being class legal does not concern me, although I still have the stock head if I ever need it for that ...