kick up rudder, two part question

[Yeadon]

I'm about to put a kick up rudder on the back of Big Food, and am thinking that I'll make the "kick-up" part of the blade out of some type of metal. The rudder will let me beach my peapod without worry. (Big Food is a 15 foot lapstrake peapod that more or less lives on a trailer.)

1) What type of metal am I looking for? Aluminum? Galvanized steel? Anything cheap and heavy? I figure that 1/4'' will do it.

2) Anybody have a photo of a kick-up rudder they'd be willing to share?

[hikingchrs]

why do you want to use metal? I have a wooden kickup rudder that works perfectly. It floats in two positions, down and up... basicly when the rudder is down it floats against the front of the upper portion of the rudder.... when it kicks up it floats trailing the boat, I still can use the rudder to steer with more force, I would not want to haul a more heavy metal rudder over the stearn of my boat. i can take a pick later if you like.
Chris

[ron ll]

Salt water or fresh? I would worry that aluminum would eventually corrode to the point of not working in the pivot. Maybe not in fresh water tho. How about a slab o' bronze? ;)

[Yeadon]

why do you want to use metal? I have a wooden kickup rudder that works perfectly. It floats in two positions, down and up... basicly when the rudder is down it floats against the front of the upper portion of the rudder.... when it kicks up it floats trailing the boat, I still can use the rudder to steer with more force, I would not want to haul a more heavy metal rudder over the stearn of my boat. i can take a pick later if you like.
Chris


Yes absolutely, post a pic! I'd love to see the rudder.

My kick-up doesn't have to be metal ... but I've really never worked much with metal and thought it would be interesting to mess with. That's the main reason. If I make the rudder and hate it, I'll go and make another one.

[Yeadon]

Salt water or fresh? I would worry that aluminum would eventually corrode to the point of not working in the pivot. Maybe not in fresh water tho. How about a slab o' bronze? ;)

Both salt (Puget Sound) and fresh (Lake Washington), though when not in the water Big Food lives on a trailer next to the house.

I could always just paint it bronze-colored.:D

[hikingchrs]

To be honest I no longer know how to post a pic here, send an email to (myscreenname)@yahoo.com and I will send a pic.
Chris

[neilm]

What about Ipe? It's heavier than water, won't rust or rot, and amazingly strong. I have taken a sledge hammer to the stuff and it won't break or dent much. It's also very beautiful.

Neil

[Barrett Faneuf]

I like wood :D . Wooden kick-up rudder being built:
http://farm2.static.flickr.com/1253/1454912730_c393c4e1a8.jpg

http://farm2.static.flickr.com/1046/1454045755_01406bc806.jpg

Installed:
http://farm2.static.flickr.com/1367/1455441489_7fd7ad24bf.jpg

and used:
http://farm2.static.flickr.com/1189/1456320734_3321531c37.jpg



The rudder is Ipe and Mahogany, with Ipe as the leading edge. I can vouch for its toughness, as I slammed it into a shoal at the Wooden Boat Festival in PT this year. The release cleat works perfectly!

[Thorne]

Try a search of the Forum, lots of similar posts with identical answers on this issue.

Bottom line is this: your lee-dagger-centerboard and rudder are the underwater foil part of the two-foil system: Sail in the air, keel/centerboard/rudder in the water.

A dead flat underwater foil will work...up to a point. A dead flat sail will also work...up to a point. Neither are most effective or fast.

Why not build your rudder in the usual NACA0012 section (12% as thick as its chord) ?

http://philsfoils.com/designTips.html

Here are a couple of photos of my oak kickup rudder -
http://www.luckhardt.com/rudder-tiller1.jpg
http://www.luckhardt.com/finishedblade1.jpg

[Yeadon]

Here are a couple of photos of my oak kickup rudder -
http://www.luckhardt.com/rudder-tiller1.jpg


That rudder looks very effective. What's your method of pulling it into the "up" position?

[JimD]

This:

http://farm2.static.flickr.com/1367/1455441489_7fd7ad24bf.jpg

...will be stronger than this:

http://www.luckhardt.com/rudder-tiller1.jpg

[Thorne]

Jim is correct, even with metal cheekplates as John Gardner designed it, the triple-thick rudder head with the center-swivel rudder blade is stronger. It also has a cleaner entry into the water, which is not the case with dual cheekplates on the rudder blade.

http://www.luckhardt.com/rudderplan1sm.jpg

To answer your question, I use a length of strong line through a tube jam-cleat, but a regular cleat would be easier. Lead weight brings the rudder down and holds it down, but others use lines running the other way to hold the rudder blade in the down position.

I really like having lead weights on both centerboard and rudder, as that means I can sail ashore or hit underwater snags without having to scramble around the boat like a maddened hamster frantically uncleating CB and rudder lines. I'm usually quite busy doing that already with the mainsheet, jibsheets, etc...

http://www.luckhardt.com/kickup-full1.jpg

[Yeadon]

http://www.luckhardt.com/rudderplan1sm.jpg



Thanks, good stuff ... which Gardner book is this drawing from? My boat was hatched from the second volume of his Classic Small Craft You Can Build.

[MiddleAgesMan]

The Aussies use rudder boxes to carry blades that are simple daggerboards mounted at the stern for steering. My Goat Island Skiff has a rudder box that at first glance seems crude. The beauty of the whole affair is that you pull the rudder blade up for shallow water sailing--just as you would do with a daggerboard. If you have it set for deep water and you hit the bottom or an obstacle it is free to kick back while restrained by the shock cord. Since the blade is not pivoting aft in shoal water you don't have to use extra effort to steer.

If you're looking for functionality and aren't concerned about (USA) tradition you won't go wrong with the Aussie rudder box.

[Thorne]

Either the combined Small Craft book or The Dory Book...can't remembah.

But since your peapod is double-ended, you'll probably want to go with one of the special stem-mounted sliding pintle-thingies used for rudders on double-enders. Otherwise I think it gets really hard to ship and unship the rudder on your type of boat.

http://www.classicmarine.co.uk/boatlists/images/elflis1.gif

http://www.woodenboatvb.com/vbulletin/upload/archive/index.php/t-3219.html

[Barrett Faneuf]

The nice thing about a swing-up rudder instead of a rudder box, is I'm not the most telepathic when it comes to knowing when I am about to hit a shoal/ledge/rock/piling :p. I use a line to hold the rudder down vs. buoyancy and forward motion. That line is held by a snap-release jam cleat. This cleat releases the line when enough force is applied - like running into the aforesaid shoal!

[Woxbox]

A flat plate will not only be less effective than a foil-sectioned rudder, it will also vibrate if you get going fast enough.

I've used lead, line and bungie cords to hold rudders down. They all work. The bungie cords and lines are nice in that you can run one to the tiller, where it can be released to let the rudder float up when needed. Bungies allow give if you hit something. If you use a line, it ought to be in a cleat that allows it to slip when the rudder contacts something solid.

There's no right or wrong way. Everytime I've rigged one, I've done it differently, and they've all worked.

[stephen e morris]

I made a nice metal blade kickup with a highway dept road sign.a very tough rustproof alloy.Got it for nothing because it was damaged.Sanded the paint off,drew the shape I wanted on the metal,and cut it out with a sabre saw.

[Yeadon]

I made a nice metal blade kickup with a highway dept road sign.a very tough rustproof alloy.Got it for nothing because it was damaged.Sanded the paint off,drew the shape I wanted on the metal,and cut it out with a sabre saw.

Now, that's what I'm talking about. Love it.

[Ron Paro]

Foil shaped 6 mm Okoume flip-up rudder. Stainless steel bolt with wing-nut to 'pinch' rudder cheeks to hold rudder in place with friction, allows rudder blade to flip-up when the rudder hits the bottom. Reach over transom and push blade down when leaving shallows.

http://bp0.blogger.com/_XuaT2XHyCMw/RoLVPSe7AfI/AAAAAAAAAW8/15PLZhrW0pM/s400/IMG_3468.JPG

See how it was built: http://jimmyskiff.blogspot.com/2007/03/compound-curve-lamination-mast-step-and.html

[Thorne]

Whatcha got in mind for a lee-dagger-centerboard? Centerboards are often harder to get to and being thinner (NACA0008 section) are more often made of metal.

Another option to consider is a pipe-rudder-head with kickup blade. Best example I can think of is Bob Smalser's gunning dory rudder.

http://pic3.picturetrail.com/VOL12/1104763/7711190/101677619.jpg

http://www.woodenboatvb.com/vbulletin/upload/showthread.php?t=8120

[Martin Pflanz]

You might want to check out the March/April edition of Boatbuilder. A guy bu the name of King built a kick up for his dugout canoe. He said that it has neutral bouyancy which might be nice for what you want.

[John Meachen]

I post this link every time somebody mentions holding down a lifting rudder: http://www.sailboats.co.uk/Product~Clamcleat_CL257_Auto_Release_Rudder_Cleat_ C257.html

There seems to be an entire nation starved of the resource,should the makers care?

[Yeadon]

You might want to check out the March/April edition of Boatbuilder. A guy bu the name of King built a kick up for his dugout canoe. He said that it has neutral bouyancy which might be nice for what you want.

Thanks Martin, I'll take a look at that.

I've enjoyed the suggestions, and with the help of the photos posted above I've come up with a pretty solid yet preliminary design that lives on cocktail napkins and in my mind. I'll be sure to get some photos posted when construction begins.

However, I still haven't heard any below the waterline metal suggestions. I know everybody loves wood, and so do I, that's why I'm here too, but this time out I want to do a small metalworking job. Other than the Sam Johnson bronze casting course at CWB, I've never worked much with metal, and the point is to learn something here. This is sort of why I always refer to my peapod as the "beta boat." It's a grand experiment where I'll design, build, test, then try something else. (Worst case scenario ... rudder fails and I steer with a oar - I promise to post photos when/if this happens.)

My goal is to create a tough, more or less effective kick up blade that swivels below the upper (wooden) rudder stock. (I'm retrofiting my current rudder into the new design.) One thing to consider, I'm more into function than great speed or amazing efficiency. I do want the final design to fit the overall look of the boat, though that factor only comes into play when you pull the blade up out of the water.

Bronze would be great, but I'm hoping to heat the house this winter. At this point, I'm considering 3/16th aluminum, which I would finish with some sort of sealing epoxy to keep it from rusting away on me.

[Thorne]

Why not a design like Bob's gunning dory above? Lots of metalwork in the rudder head (pipe) as well as the pivoting bits. You could even make the blade from metal if desired.

Don't think that most of the suggested rudders (including mine) would work really well on your boat, due to the angle of the rear stem and other factors. Anything very wide will create a lot of drag when submerged...

Big Food being launched -
http://farm2.static.flickr.com/1362/618406991_f7cbb9a206_o.jpg

[Yeadon]

Here's a couple more reference photos of what I've got right now ... a push/pull above a rudder that doesn't extend far enough under the waterline to really give me the control that I'm after.

http://farm3.static.flickr.com/2326/1693548880_2bb2412bff.jpg

http://farm3.static.flickr.com/2128/1771046390_07d5432d3e.jpg

[Thorne]

Not to harp on the gunning dory rudder design (wink, wink, nudge, nudge...)

But note that the top/head of the rudder blade **starts** about the place the bottom of your fixed rudder blade **ends** -- plus much less drag aft of the rear stem.

So you'd get the maximum depth with minimum drag, plus all that lovely metalwork...

http://pic3.picturetrail.com/VOL12/1104763/7711190/101677619.jpg


http://pic3.picturetrail.com/VOL12/1104763/7711190/101677609.jpg

http://pic3.picturetrail.com/VOL12/1104763/7711190/101677187.jpg

[Yeadon]

As a quick update to everybody ...

I've begun working on a kick up rudder made of a nice piece of purpleheart that I'd forgotten that I had.

Here's a photo I took earlier this evening. The plate is a plywood template, which I'm still fiddling with.

http://farm3.static.flickr.com/2017/2249947944_edf42bb783.jpg

I'm following this design by John Gardner.

http://farm3.static.flickr.com/2416/2225650448_1cb5253e95.jpg

I still have a bit more fairing to do before I actual begin finishing and assembling the rudder.

http://farm3.static.flickr.com/2294/2249151327_5c4293f779.jpg

I have a lot more description on my blog: part one (http://superyeadon.wordpress.com/2008/01/17/big-food-time-for-a-new-rudder/), part two (http://superyeadon.wordpress.com/2008/01/27/big-food-kick-up-rudder-project-continued/), part three (http://superyeadon.wordpress.com/2008/02/07/big-food-kick-up-rudder-iii/).

[Thorne]

Looking good!

Be prepared to do some final shaping of the blade once you get the cheek pieces made, as you want to have it pivot up high enough to clear the ground even when pulling the boat up on a steep shore.

I ended up doing some sanding and fiddling even after riveting the cheekpieces on, as I wanted the rudder to be solid in the fully-up position. Occasionally I operate it in that position and it works well for sailing in very thin water or up onto the beach with the CB pulled up.

[katiedobe]

GReat Link. Thanks.

[ahp]

I know it may be made of that other stuff, but look at a photo and/or a plan of an O'Day Daysailer. The organization has a web site. It is very simple. The blade is weighted so it stays down unless it hits something. It could be copied wood very easily.

[Yeadon]

Looking good!

Be prepared to do some final shaping of the blade once you get the cheek pieces made, as you want to have it pivot up high enough to clear the ground even when pulling the boat up on a steep shore.

I ended up doing some sanding and fiddling even after riveting the cheekpieces on, as I wanted the rudder to be solid in the fully-up position. Occasionally I operate it in that position and it works well for sailing in very thin water or up onto the beach with the CB pulled up.

Thorne,

I saw you've attached the lanyard/line that you use to pull up the blade about a foot or so below the bottom of the plate.

How do you like that location? Is it below the the waterline? Any complaints?

[Thorne]

The 'fully up' position is still below the waterline, in fact I occasionally forget to lower it and sail with it up, works fine either way.

The essential bit is having it up high enough to stay off the bottom when the boat is pulled up on shore a bit, so the blade and pintles don't get hammered with passing wakes or waves.

[Yeadon]

Got that, thanks ...

But do you wish that you'd tied the line further down on the blade? As in, is the blade easy to pull up and maneuver, or do you wish you had a bit more leverage?

[Thorne]

Nah, it pulls up fine, but even with a lot of lead, I still have to push it all the way down when in the water -- and it swings back a bit when the boat really gets moving. No problem with that as I think every bit of CLR aft helps with the otherwise heavy weather helm on my boat.

Go out and buy some really strong line for this pennon, as it needs to hold the heavy blade up when launching, retrieving, and sometimes sailing the boat. Don't use soft line that may wear or break....don't ask me how I know this.

;0 )