building new rudder

[mark in toronto]

I big chunk of my rudder came of this season when the remnants of Katrina hit us while we were at anchor. Not a pleasant night. It was originally layers of marine plywood with a thin coating of epoxy. I'm about to go shopping for new marine ply to start building a new rudder. How does it come when you buy it? Can you get it already planed to a tapering shape? My apologies in advance for the dumb questions.

[mmd]

It comes in big flat pieces that you have to cut, plane, and sand it into shape. That's what boatbuilding is, and why it's fun. ;) :D

[Ian Marchuk]

Smarty Pants Nasal Artichoke

[ 10-14-2005, 09:46 PM: Message edited by: Ian Marchuk ]

[JimConlin]

There's a very long, very bad joke whose punchline is "Artie Chokes Two for a Dollar".

I'll spare you all.

[JimD]

Noah's is in Toronto, I think. Windsor Plywood sells marine douglas fir, too. You should have no trouble finding it. And yes, it comes in standard 4' x 8' sheets.

[Ian Marchuk]

OOPS, my drawings for the M36 probably just went up 200 bucks.....

[Wild Wassa]

You can buy rudder blanks, coated and uncoated and V bag finished ... they cost a small fortune.

When you see the cost of a rudder blank uncoated and then the cost coated and the quality of a professional finish and the price ... buy a half sheet of marine ply or a nice wide straight plank ... then get the grinder out. You will make a rudder for a third of the cost of a shaped uncoated rudder and shape it all in a morning.

Painting and polishing the rudder, allow a month for a few good coats a fine finish and a good hard polish. You will have better than you lost.

The sealing of the timber and painting (or varnishing) slows everyone down. It requires little actual work but lots of hanging around.

Warren.

[ 10-14-2005, 05:49 AM: Message edited by: Wild Wassa ]

[John Meachen]

Can you tell us a little more about the boat and its use?Without knowing a bit more,it is difficult to offer useful advice.Wassa's advice is probably good unless you are a fanatical racer.In which case you will need to pay a professional to do a job that will not hold you back.If you have ever tried to make a well finished,true foil section you will appreciate what a bargain they provide.
(edited for spelling)

[ 10-14-2005, 07:30 AM: Message edited by: John Meachen ]

[Steve Hornsby]

Mark in the Big Smoke,

I second the referral to Noah's. They are located in Etobicoke, just north of the Queensway. Get a sense of the size and thickness you will need, take it in and the guys in the shop will take care of you.

Steve

[Alixander Beck]

I will Third Noah's as an excellent resource.

Mark, I would hesistate to use plywood for a rudder contruction. It is difficult to get a good shape to plywood without checking.
I would recommend either laminates of wood (spruce etc.) or solid board. They will produce a better shape, have better working qualities, look better and be stronger.
A layer of Glass over the rudder would be a good idea too.

Here is a link to picutres of the rudder I have just built from BearClaw Pine to a NACA 0012 section shape.

http://boatdesign.net/forums/showthread.php?t=8975&page=2

I am also in Toronto

[mark in toronto]

wow ... it's been a while since I last posted and I'd forgotten the depth of knowledge available here. Thank you so much for your input. I'm on my way to Noah's today to get their advice. I'll try to post a pic of the damaged rudder now that I've removed it from the stock. It appears my vessel's previous owner either modified or repaired the rudder inexpertly and a fault line of rot was the result.

[JimD]

Mark, I would hesistate to use plywood for a rudder contruction. It is difficult to get a good shape to plywood without checking. I had a different experience with a DF plywood rudder and found it faired with a belt sander very nicely. A layer of glass cloth was added.

[Alixander Beck]

It does work well with a sander that is true, I guess I should have specified that I was using a spokeshave.

[Noah]

A power planer also works pretty well for big changes. I made a rudder for my Folkboat a couple of years ago out of marine ply, and it can out great. No need to drill drifts, etc. I got a great shape with a power planer, grinder and random orbital sander. It really doesn't take too long to shape it. Then go at it with goop and glass.

[whb]

The thing about shaping plywood is that it already has reference lines built into it so that it is really easy to see if your shaping is fair.

Howard

[Wild Wassa]

Originally posted by John Meachen:
"... you are a fanatical racer.In which case you will need to pay a professional to do a job that will not hold you back.If you have ever tried to make a well finished,true foil section you will appreciate what a bargain they provide."

John, I totally agree, good rudders are a (expensive) bargain. For example a V bagged rudder for a Heron is $400, a new rudder for a Flying Fifteen is $600, both purchased from manufacturers.

Making a perfect foil takes me ages, that's if I can even get close to perfect, reshaping old ones can be just as taxing.

There is no one shaping. I do multiple coatings with multiple shapings and I've hardly done anything except correct tiny flaws ... they endup looking right and working well though. I do like working on foils because of the challenge ... I find it very rewarding, handing a foil over.

14 wooden foils I did over winter ... new or restored. Early stages for a selection of the rebuilds, for a Moth, Heron, Miracle and Seafly, enjoying last winter's sun. All were in bad shape. Lots of epoxy and glass bubbles fixed them. The panel (the odd one out), is a salt textured anti-skid curing in varnish. I also restored foils last winter for NS14s and Lasers. I'm about to start work on restoring foils for a Fireball. All the foils were cut and polished.

http://www.imagestation.com/picture/sraid190/p5173907e73604f7ecbdf988fe154127b/f1e3aa56.jpg

Warren.

[ 10-14-2005, 07:18 PM: Message edited by: Wild Wassa ]