Hi all,
I need some advice on what timber to buy so I can make a new rudder for my Red Witch. The rudder broke in half when it drifted in to shore during the night at Geordie Bay Rottnest. I found some builder's ply in a skip bin and that's how I got home(see photo).
The original rudder is solid timber and I want to use timber to make a new one. A friend says it looks like oregon; this is hard to find in Perth so I want to know what other wood is suitable and where can I find it in Perth. The list I have so far is:
1.oregon 2. Tasi Oak(maybe). Any advice greatly appreciated.
Timber only then its Tasmanian oak. Personally I would use construction ply, not the plastic coated stuff in the photo but the ordinary stuff. Its glued with recorcinal glue so is waterproof and is easy to shape using the layers as a guide. Sheath with about 3 layers of cloth and epoxy resin, steer clear of fibreglass resin. Strip of carbon fibre cloth down the centre of the blade from the cheeks down about half way laid up between the layups if you have it.
If it were my boat I would use any long grained timber, preferably a relatively light one, Oregon being one Huon Pine being another. Both of these timbers are hard enough to have a certain mechanical strength and withstand a bit of abuse. Don't be put off by the cost of these timbers as you are not going to be using that much to build a rudder. Furthermore don't fret if you can't buy big slabs, just use smaller pieces and laminate them making sure to alternate the grain direction to prevent warping. A laminated piece is stronger than a solid piece anyway, so good reason to do that. Wipe all timber down with acetone before gluing to ensure no natural oils remain.
Wrap it in glass cloth if you want using only epoxy resin as the others don't stick to wood, one layer of glass is ample as it is only there to prevent abrasion. It adds nothing to the strength of the timber, only weight as the wood has a higher tensile strength than the glass anyway.
Try Fremantle Timber Traders at 41 Wood street, they specialise in recycled timbers.
Thanks for all your advice. I intend to check out a place called AllWood Timber supplies and see if they have any Tas oak, oregon, or huon pine. Will keep you posted. Timber Traders had a piece of oregon but it was badly split.
Hi Rotto,
first of all well done on the replacement rudder, thats a great job!
my redwitch rudder has broke twice before and I have had my most recent made from the original fibreglass mould with a timber core.
I originally had an oregon rudder, but that broke at the lower rudder gudgeon after it developed a vertical split
The next rudder was fibreglass with no core and hollow at the water line, all it took was a bit of load from surfing and that went too (coming back from rotto...)
My new rudder was made by Brett Burvill at Windrush Yachts for $890, it's a pretty reasonable price, and takes the effort/stress out of making one yourself 
.
the finish was pretty good, but the moulds are very old, and have a few dings in them
I can hook you up with the moulds if you want just pm me, or email [email protected]
See my previous post about a strip of carbon fibre down the centre each side of the blade. Most of the load will be exactly where goingtorotto's blade broke. Other weak point is where the bolts are for the gudgeons. The strength is in the skin, the timber is just a core and epoxy cloth layup with a reinforcing strip of carbon is far stronger than fibreglass can ever be.
Doing it yourself would cost less than $100.
In gointorotto's case the rudder breaking like it did is better than having the fittings tear a hole in the transom which would have been awkward!
Bit late - hard to find here - Cedar, made rudders for dingy's and Olson 30's and everything in between.
On Saturday I ordered a piece of Oregon from AllWoods - $87, 1800 x 300 x 50. I guess I'll get them to cut it into about 6 strips. The last rudder which was just oregon with a thick coat of epoxy paint was fine; the reason it broke was entirely human error - I anchored the boat too close to shore and it ended up lolling about on the sand all night. Tiller was tied off too so that made it worse.
Red Witches are often bought by people new to sailing and it's just as well my friend and I have a simple boat that's cheap to repair as we are learning by trial and error.
Six months ago he broke the boom in half - could have been corrosion . . . could have been over tightening the vang. The good news is we simply bought an identical aluminium section from Tasker's($70) and re - attached the stainless steel fittings.
Looking forward to getting out on the water again.
So every 2nd strip should be flipped over not just horizontally but vertically as well ? The original rudder seems to be made of just one piece of wood; do you think that could work again?
Just end for ending will do.
And as was said above, rough up the glueing edges.
When using oregon to make a keel core before I used Bote Cote 2:1 epoxy thinned with their product called TPRDA to coat all the glueing edges first, went and had a coffee (let it go off a bit) and then came back and used their 1:1 glue it all together.
The reason for the thinned down mix is oregon can be very porus (sp) and combined with a little bit of over tightening on the clamps it can mean no glue left in the joints.
Reversing the grain prevents the plank from warping. Would have been better to buy 50mm x 50mm oregon. Cheaper, its a shame to cut that 300mm wide plank! Scary the price of timber these days.
Chord of original rudder is 10" - 25.5cm, so have plenty of wood. Just waiting for it to arrive now.
Picked up wood yesterday from AllWoods. Doesn't look like the best cut of timber; as you can see it's taken from the outside of the log and has many knots. Hope it will be strong enough when glued together.
Is this the best way to arrange the wood. Won't the alternating grain direction make it difficult to plane? I plan to use a router and then plane.
Bottom picture is close to the mark. I was up at my mates place yesterday. He has his hollow oregon mast across his yard, its an enormous stick which weighed 520 kilos when we craned it off. He had to scarf in several feet of oregon to the top section. The oregon he used was secondhand from an old house in Sydney, perfectly clear, not a sign of a knot anywhere and quite tight grain but easy to plane. Very hard to get decent "new" oregon about now.
Easiest way to shape is with a disc grinder with 36 grit paper, lot easier to get the correct profile with plywood of course. That's going to be a bugger to plane.
Firstly let me say how disappointed I am in the quality of that timber, even given the poor quality that is around these days for the money you paid I would have expected better.
If you have access to a power plane, use that on a fine cut setting to rough out most of the shape and then as Ramona has said, use a coarse disc sander getting progressively finer as you near the finished shape.
I would suggest a template of the profile your aiming at to aid in the shaping. Maximum thickness about the third of the way back from the leading edge, rounded leading edge and have the rear taper down to a sharpish edge.
Have a look at an Eppler E836 foil shape, this is what you should be aiming for. Forget those super skinny NACA foils, they are too thin and will stall ,whereas the Eppler foil has a high angle of attack before stalling. Also don't listen to talk of laminar flow (which uses skinny foil shapes) as on a yacht, the flow will always be turbulent not laminar.
I intend to use a template and just base it on the old rudder which is 10" x 2" at thickest part. I'll make sure template is perfectly symmetrical before starting work.
Rudder update: Laminated timber using epoxy. End to ended the strips of wood and tried to arrange them so no knots near the lower gudgeon - where the rudder will tend to flex. After routing, gave it a light spray of paint to act as a guide when planing. Has been sanded and have used some filler because of the knots and . . . one routing mistake. Will glass it after we finish shaping ends.
Once I cut a cross section of the old rudder it was interesting to see that the original wood is probably cedar.
Thanks. Yeah we used epoxy- West System 205 I think it was called. Finished it off with a 2 part epoxy paint. Will put rudder on boat tomorrow and I'll post some pictures. 
Rudder works well and I think it's very sturdy. Used grey priming and then a very expensive epoxy paint for marine use. It looked great but paint has now blistered all over - before we put it in the water. I think my mate waited about 8 hrs for primer to dry; maybe not enough time.
