Fair existing rudder?

[ebb]

The original rudder with mid-plank peep-holes for nuts on internal bolts, really
bothers what's left of the carpenter in me. "I know, I know, it sounds like I'm
belittling the (rudder), I'm not, but it is a creature of its time. It's like an 80s
(read 60s) rock anthem: cheesy, and nostalgic, and taken SO seriously by the
(shipwrights) who (built) it." {rewrite from a literary quote of my daughter's}

Here is an idea for a revised version of the old rudder
with two part 1" 655 shaft and 3/8" internal threaded rod that allows pre-drilled
mahogany parts to assemble consecutively and bolt logically into a single united
rudder. What follows could be enabled with diagrams and a lot fewer words.


Looking at the original rudder with swiss-cheesy holes + some rather awkward
fastening layouts: the rudder makers must have done things differently a couple
times over the model years... there has to be more logical ways to "tie" 3 plank
rudders together. Here, generated straight out of the original concept, is a way
to get all the planks to share and stack on a 3/8" internal bronze rod framework.
Can be assembled on the workbench with every fastening in place. This simpler
straightforward method, so far as I'm aware, hasn't been done yet...

Assume that a new 3 plank rudder with all new materials is the plan. Looks like
we'll have but seven tie-rods. That is: only seven fasteners!!

Memorize or make a copy of aoquinn's revealing blue rudder photo, so fastener
layout is right in front of us. The first plank, the one with a cutout, shows six
medium length bolts that look like they pass right thru the shaft. Three thru
the top, three thru the bottom shaft piece. The way I see it, it's really strange
the bolts don't just extend thru the plank to its seam. Assume the shaft is thru
bored for the bolts -- which are, in my opinion, well positioned on the two
shaft pieces. But we'll end up tweeking bolt positions a bit....

PARADIGM SHIFT #1
The two angled bolts seem to be lags, they hold the bent leg of the shaft along
with the first bolt at the very top where the shaft is 'straight'... to the first plank.
Let's straighten the bolts out, right there in place, so that the top three -- and
all 6 -- are parallel and 90degrees to the rudder shaft. The shaft will reguire 3/8"
(actually they will now be 5/16" or Letter Q sized tap) holes drilled thru the bent
stock, at about a 64degree angle to the plane of the 1" stock. BUT Instead of
thru boring the holes, a machineshop can easily get enough thread - 3/8-24 - in
angled blind sockets - so that these two connecters are not exposed in the prop
opening. Likewise, best plan for the other four 'bolts': they are NOT drilled thru,
but partially thru, and threaded for rods.

We now have the six fasteners all parallel and (to the rudder's 2-pc length) at 90`.
Now, let's get rid of the cheesy peeps by drilling completely thru the width of the
plank. We'll screw hexnuts onto 3/8" bolts in the seam, along the side. These
'bolts' are screwed into blind threaded holes in the shaft. Yes, they aren't bolts.

P.S. #2. Wait a moment. Let's take that second bolt and lengthen it to include the
width of the second plank. Let's call this headless bolt a tie-rod. Tie-rod screws
into the dogleg shaft, goes thru the first and second plank, ends in a nice tidy nut
in the seam between the second and third planks. Nuts will have cozy little caves
to sit in, in the side of the third plank.
While the stock/rudder shaft, is prepared at a machineshop with blind threaded
sockets (they do not go all the way thru the 1" shaft), tie-rods are custom cut to
length by the skipper and ends threaded on site with a manual die cutter.

Middle bolt of the three in the bottom shaft piece is treated the same. Becomes
a tie-rod threaded into the shaft. Goes through both first and second planks....

All four of the other first plank fastenings are bolted thru the first plank, cinched
up in the seam with an unburied nut. We do away with peepholes. Honduras
mahogany, such a fine and dandy wood!... don't need no stinkun peepholes!

P.S. #3. There is that canted rod in the middle of the blade in our blue rudder
photo that looks a little too short and lost. Let's bore (at 90`) a short hole thru
the deepest part of the curve in the prop cutout thru the first plank. Continue
thru the second. And the third! Have now tied together three planks, not joined
with the rudder shaft, hexnuts at both ends. Nuts remain exposed but inset in
shallow counter bores. A major fastener is now created for the outer plank thru
its widest section in the middle of the blade. (We have, of course, separately
pre-drilled all holes thru the planks prior to assembly. No improvisation.)

How are the pointy 'ends' of the third plank securely fastened to its mate?
(ebb has a major problem with those two extra l o n g slanted bolts that end in
peeps.) One inhabits the top portion of the blade. It's real purpose - for the
original maker - was to somewhere get a fastening somehow thru all three
planks. But there's a poverty of wood being used at the tip of the third plank.
Bolt there is so awkward that it looks like an afterthought for the work asked of
it. Head is too far out on the tip of the plank to inset hexnut in enough wood.
This long angled bolt and the one in the bottom half of the blade.... are history.

PARADIGM SHIFT #4
OK, there is a solution. Look again at the two tie-rods extended thru the second
plank in top and bottom sections of the blade. What happens when we lengthen
both tie-rods again, by leading them thru the outer plank? Take a plastic square,
draw a 90` pencil-line - on the photo - from the shaft across the blade. Yes?
Tie-rod extended is comfortably inboard of both pointy ends, (...well, maybe the
bottom tie-rod extension needs repositioning) with enough meat for hexnuts to
hide in shallow counters in the curved outer edge. Alongwith a middle 3-plank
tie-rod, we now have effectively tied the whole rudder together!

When first laying out the rudder for these fittings on white cardboard, we can
tweek the original layout a little. Move the last 'medium' bolt/tie-rod up a skosh
here, maybe add a little 3 or 4" half-tie stub from the shaft out into the very
bottom of the blade. (see original rudder drawing with proposed layout in red)

This 7 tie-rod layout, imco, binds three planks and two sections of the shaft into
as much a whole together possible with the fewest tie-rods. All 3/8"d tie-rods are
parallel IN THE BLADE allowing planks to be shipped and unshipped as stacked.
2nd & 3rd planks each have three thru-holes for stacking, two of which are
directly connected to the shaft. Easy to assemble. Initial accurate layout and hole
boring is crucial. But they are always 90` and always centered in the plank.
The cheat here is to oversize the stacking holes a bit. Make them 7/16"d.

HERE"S HOW THE NEW TIE-RODS LINEUP
>using the rudder blade visual from the PearsonAriel Manual<
Looking at the photo: Blade is down, top of rudder is to the right: All rods parallel:

First tie-rod: from shaft thru first plank. Second rod: 90` from shaft* thru 3 planks.
Third rod: 90` from shaft* thru first plank. (*These are the angled holes.)
New tie-rod: throat of prop cutout thru three planks.
Fourth tie-rod: from shaft thru first plank. Fifth rod: from shaft thru all three planks.
Sixth rod: shaft thru first plank. No peepholes. No extra long slanted bolts.
Tie-rods 3 and 4 can be separately extended to include the second plank, but would
not be accessible. Adding extra weight to this already heavy rudder isn't smart.
Seventh, 1/2 tie-rod: short stud threaded in shaft in the bottom of the blade.
Total: 8.

The three 3-plank tie-rod nuts can be loosened or tightened at will if the nuts in
the outer edge of the third plank are accessible. Shorter tie-rods are inaccessible,
but assume wood movement thru the first plank is minimal. Rudder can be thought
as a "bolt together", as it may be taken apart when put together with maintenance,
repair and re-bedding as an option.

There is more to this story. (e.g....boring accurate holes thru planks..)
FEEDBACK
please CRITIQUE THE DESIGN !
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SEALING
Always, after final sanding is done, mix undiluted, no-blush, laminating epoxy and
scrub into the finished work. Soak, especially end grain, then rub remaining liquid
off with terry rags to get it 'dry'. When epoxy sets, it will be smooth and burnished
requiring little sanding. Crust will help keep wood from getting fuzzy when bottom
paint is stripped.
LeTonkinois #1 varnish can be used like oil underwater. Don't expect to apply 6
shiney coats for fishes, use it like epoxy: roll on two coats, rub it in, rub it off
while still wet. Being nice in a natural way for the mahogany angels.

A strong case can be made for sealing each plank individually, before assembling.

I'd use 1/8" Tremco butyl tape to bed the rudder pieces together. Nobody knows
why manufacturer's have to say we can't use it underwater. Protected between
surfaces, why not?
Butyl Tape Underwater - Sail Net Community, 4/06/2009. 17 posts.

imco

[Caferacer59]

Ariel 417 has a new mahogany rudder and Bronze shaft, back in the water tomorrow and racing wednesday. My insurance company was fantastic, the rudder is as original, thanks Mr. Phelon for supplying the new bearing. here's to 50 more years for the ol' girl . Cheers.