big rudder problems / problemas masivos de timón

[willyd]

So, my rudder snapped in half. The boat is a 1964 Whitby 25. I just had it hauled out and on a whim removed the rudder, and while poking around near where the main rudder stock meets the cheeks of the rudderhead, I discovered two places where there was rot. The next day I brought the rudder home (it's massive and barely fit in my son's car), and while trying to separate the cheeks from what I THOUGHT was the repair I'd be working on, the rudder snapped in half where the upper pintle was located. (short story ends here). Longer story - it turns out that at some point, to repair what I assumed was loose bolts due to rot, some dummkopf had simply unbolted the pintle, moved it forward and rebolted it using two instead of three bolts, without even filling in the holes left over.

Anyways, I would like to get folks' advice on how to proceed. I've removed the upper section from the rudderhead cheeks. My plan was to start digging into the section below the break (the gray area is wood, the black is fiberglass over wood, below that, not sure), then expose a 4-5" section of good wood to form a simple scarf, then use epoxy to replace the missing section with either a solid piece or one laminated from staves of wood, then fiberglass everything before bolting things back together.

The part that broke (the main body of at least the upper part of the rudder) is white oak. Lower down it becomes what appears to be solid fiberglass, but may be an oak core with a ton of fiberglass covering it. The rudder must weigh 100 lbs and is 11' from the lower gudgeon to the rudderhead.

While I want to make as strong a repair as possible (will staves even work?), I might add that I don't believe the stresses on the part I need to replace are as massive as one might imagine. Unless the sails are excessively out of balance, the boat can be steered with one finger, and that unbelievably shoddy repair lasted for at least the nine years I've owned the boat. It broke only when I, in my basement, see-sawed the rudder up and down to try to knock the upper part free of the cheeks while it lay sideways, pivoting on the area near the upper pintle.

[psk125]

We can't see how the rudder blade is constructed. That would be helpful, to see how the top section of the blade (which broke) ties in with the rest of it. They're usually made up of stock - possibly 2x10's or so - that gets drifted together edgewise. If that is the case, it would probably be a good idea to replace the whole top/front piece of the rudder, from the prop aperture opening to the top that goes into the rudderhead cheeks. Repairing the broken section with an epoxied scarf might work, but obtaining the 12:1 angle you'd probably want to use for the scarf would cut a good way into the whole top/front piece of the rudder anyway, possibly making removing/replacing it a more obvious and simpler approach. If you do go with the scarf, you'll of course want to cut the scarf on the flat, so there'd be more surface for the epoxy to hold things together. A bird's mouth scarf might be suggested as well, for extra strength. Good luck!

[tkeithlu]

I think that I understand the problem from the photos. I'll give it a try.

I do not think that I would attempt a repair. The rudder has rotted above the waterline, suggesting that the lower part is not going to be much better. The point where it broke is the critical point for any force applied to the side of the head, as in someone leaning on the tiller. It also is critical for turning (the normal job) because it is right above the pintle. I suggest that you consider using the existing rudder, the entire gray part, as a pattern and make a new one.

The question then would be the material. Marine grade plywood is an option, as is laminated hardwood. I'm not much of a woodworking person, so if you are interested in that route I suggest you talk to a furniture maker, wooden boat builder, or finish carpenter. In either case laminating on a fiberglas jacket is in order.

I'm pushing you toward a big job, I understand. But, your rudder is more than kind of important to the safety of your boat, and you are damned lucky that it snapped in your hands rather than between two jetties on your way out to sea.

[Spot]

I would beef up the red part between the tiller and the rudder, seems like it would forever be twisted between the forces on either end. Perhaps more of a box section (twice as thick) then skinned with fiberglass cloth and resin.

[Singularity]

Another option is a tennon-type repair using FRP pultrusions embedded into the wood 'up and down' after which the skin would be wrapped with new glass, invariably requiring a new, more accommodating pintle. You'd need a jig to be able to drill accurate holes for the FRP rods to be embedded.

Where wood is replaced, consider using Coosa. Otherwise you might glean something from this rudder repair:
Phoenix's Flight: Search results for rudder

[TrentePieds]

I agree with tkeithlu. Repairing is a waste of time since this rudder is not only constructionally simplicity itself but also transom hung. And as you yourself point out: This boat balances beautifully. Because it is a barely disguised Folkboat ! :-)

The "siding" (thickness) of this rudder is about the same as the nominal 2" dimension of a common 2 x 4 stud as used in shoreside construction, call it 1 3/8". On a sheet of plywood draw the outline of the rudder. This plywood is a "building table" known in the trade as a "screeve-board" - literally a board you "screeve" (write) on. You can trace the rudder shape using the broken bits as a template. Cover the screeve-board with clear plastic so you you can see the outline of the rudder through the plastic.

Then cut sufficient number of 2x4s to length to cover the rudder area without more than necessary sticking out beyond the outline. The strakes should run "the long way", of course, and lie on their "wide" side on the board. Use red cedar or other rot resistant wood for this. Your lumber yard will have it or get it since RC is used for fencing. Do NOT use "SFH" ("spruce-fir-hemlock" construction timber) for this! Get the material "S4S" ("Sanded 4 sides") to save yourself some work.

Use epoxy glue to glue each strake to the previous one. You can use ordinary pipe clamps to hold the strakes in place while the glue cures. When all is solid, trim the rudder blank fair to the outline, (having again traced it from the broken bits) with a SawsAll or similar reciprocating saw - a jig saw is too small and wimpy. Sand or grind the outline fair and square to the sides of the blank. Then scribe a line at mid-thickness all around. With the grinder, or better still, with a belt sander, grind the sides of the blank till you get a nice "foil" on the blank.

At this point you can "bright finish" the new rudder with epoxy, or you can clad the rudder in fibreglass. Way back in the 1940s when your boat was designed we didn't have epoxy or fibreglass and this kind of rudder was either "bright finished" with spar varnish of painted with "white lead varnish", i.e. white paint. Bright finishing has the advantage that you can see the state of the wood underneath, but paint is obviously easier to maintain.

On this type of rudder, the tiller was usually held in place by oaken "cheeks" that formed a socket into which the tiller fitted. I cannot conceive of any better way to do it :-)

Hope that helps. Do come back to us, if you need more help!

TrentePieds

[willyd]

Thanks much for all the advice! I'm fabbing a temporary repair to bring her home, then will see what works from there. I appreciate all your help.