Rudder assembly ideas...

[Art Read]

Went to the local marine swap meet a while back with my pending rudder construction on my mind. Ran across a truck trailer full of what appeared to be nothing but spare parts culled from various scrapped boats. Found this rudder post stuffing box from an old Chris Craft still attached to it's rudder and part of the keel.

http://www.imagestation.com/picture/sraid19/p75b49587f1b353de6c57a6f11ffcbb25/fdc70af8.jpg

I'm wondering if perhaps I couldn't adapt this to my purposes? Obviously, I'd have to mount it on an angled backing block to match the rake of my rudder post and I'd want to somehow "extend" the rudder post "tube" to pass all the way through the backbone. The threaded cap on top would only be a few inches above the waterline, but that's how it worked on the Chris Craft too, no? After having taken it apart, I'm not entirely sure just why/how it keeps the water out. Just a very close and well greased fit between the post and the stuffing box? Assuming I can get a piece of bronze rod for my rudder post that will exactly match the rudder post from the Cris Craft that I took out of there, it should work for me too, shouldn't it? I'll still have to come up with some sort of "bearing" for the upper end of the post where it comes up through the aft deck but it seems to me this might be a more "elegant" solution than just running the post up through a length of copper pipe to the deck as I'd originally envisioned? How can I go about extending that "tube"? Braze a piece onto the end? Fit a slightly larger copper "sleeve" over it? I can't see as how it has to be real strong. It'll be built into the keel after all... I just want something other than the wood of the keel itself for the post to bear against as it passes up into the hull. Thoughts?

(BTW... This just came with the deal... I imagine these aren't exactly easy to find these days. Suppose it's worth figuring out how E-Bay works?)

http://www.imagestation.com/picture/sraid19/p94cfa68f6e493e066ee6aa68957714b3/fdc70afa.jpg

[ 04-28-2002, 05:51 AM: Message edited by: Art Read ]

[Mike Keers]

Your understanding of the rudder port is on target. What keeps the water out is flax packing rings inside the stuffing box, just as for a prop shaft.The ports and rudders come in standard sizes, usually 1-1/8", 1-1/4", 1-1/2.

As to the length of the spigot, no joy there except to pass on that they come in different lengths from about 4" up to 10". I looked for quite some time for one that was at least 8 inches long, and finally found a new/old one at a boat junk place (and paid about 1/4 of retail). Like you, I needed it to extend thru the keelson and hull. Depending on application, sometimes a backing plate is used outside the hull, that matches the base plate in hole sizes and pattern.

The rudder you show isn't that rare at all, and are commonly found on eBay for around $25. They also still make them new, for quite a bit more.

For a plain bronze top bearing check Hamilton Marine or any other similar chandler. They sell just what you need for about $25-30.

You don't mention what type of tiller you'll use. For a wooden hand-held one you'll need a rudder head (tiller head) fitting, again available in standard sizes and keyways(look for used). For a below decks 'remote' steered boat, short bronze ones come in standard sizes, bores and keyways too, about $25-40. Or maybe you'll be using a quadrant with cables?

If you're using stock bronze rod to construct the rudder shaft, you probably want to stick with standard size stock and keyways, for compatability with the other parts, as above.

[ 04-28-2002, 12:26 PM: Message edited by: Mike Keers ]

[Art Read]

Thanks, Mike! I figured there ought to be some "packing" of some sort in that stuffing box, but damned if I could find any when I disassembled it. Seems like it was just a VERY tight fit, (almost like a cone shaped seacock "fits", if that makes sense) with a real thick grease keeping it "limber". Perhaps somebody else took it apart before me and didn't bother to re-pack it before throwing it in the "for sale" bin? I'll have to look at it again... I don't remember there even being an obvious place to put it in there. Maybe there IS some there and I just missed it...

Re: the spigot, (so THAT'S what that's called!) well, I'm keeping my eye open for a more suitable piece of gear that won't require all this jury rigging... hell, I only paid a few bucks for the whole thing, rudder included, but I assume you don't think "extending" it or fitting a "sleeve" would answer? I'm trying to visualise the physics involved here and can't really see why I need anything more than a well fitted "tunnel" through the keel for the post to pass through. A brazed on extention would be easier to waterproof and fit, but couldn't a well bedded and sealed "sleeve" serve as well? As long as the water can't get up and out under the rudder port flange and into the boat? I'm sure I'm missing something here....

As for the tiller head fitting, I've actually had a nice bronze one sqirreled away for quite a while now. I found it at a marine exchange here in Seattle and it "appears" to be sized for the same size post as this rudder port, believe it or not! (One inch...) It does seem a little "beefy" for a delicate, little boat like mine, but I don't think it'll be "too" obtrusive. I'll have to make the tiller with an inch and three quarter base, but tapered down along it's length, it may look all right. We'll see. I can always change it out again later. It is missing the key though. Hard to find those? I haven't bothered to look yet.

Thanks for the heads up on the top bearing. I'm sure I've got a Hamilton catalog around somewhere... Yet another thing I haven't really searched out yet...

Beggining to wish I had picked a transom hung rudder design! ;)

[ 04-28-2002, 05:47 PM: Message edited by: Art Read ]

[cdm4]

You might also try http://www.marineassociates.com/page6.html or http://www.csun.edu/~bxw52916/glenwood/catalog.htm They have a lot of that kind of stuff. CM

[Mike Keers]

Art,
I'll bet you a donut hole that there's packing in that stuffing box. The stuff is woven and impregnated with wax or sumpin' and after years of people tightening and tightening, not bothering to change the stuff, it sort of coalesces into a waxy solid-looking stuff. Try picking at it.

For those not all that familiar with stuffing boxes, they do work on a wedge sort-of principal, the packing is wrapped around the shaft (usually three rings, ends taper-cut to fit together and the joints staggered like piston rings)and the inside of the cap nut is chamfered, so that when it is tightened down the packing is compressed against the shaft.

I don't have much positive input on extending the spigot, altho' you seem to have a handle on an idea or two. As you note, the important thing is to keep water out of the space between where the spigot exits the hull, and contain the water inside the tube. Maybe I don't know how it's done really, except I've seen the backing plate I mentioned earlier with sealant under it. I guess on a timber-framed vessel, it might not hurt to have water get in around the spigot, as the sealant or bedding under the mounting plate keeps it out of the boat. But on FG or cold molded and ply boats, I think it should be sealed on the outside. Now on the CC boat that rudder came off of, the spigot also acts as the rudder bearing, so a good fit with the shaft is essential. But if you're having an upper bearing, and possibly a lower shoe or skeg, the spigot isn't acting as a bearing/bushing.

I had to search for about a year on eBay and at boat junk places to find the one I wanted for teh boat I'm building....1-1/4" shaft and a spigot about 8" long. I finally got one for $35, new, but buried in a crate of old stuff at Minney's in Newport, Cal.. Of course I could have simply paid about $185 from Hamilton or elsewhere...but that ain't my style! :D

[Art Read]

Just so, Mike... When I looked again today, sure enough, there IS packing in there after all. Just so hard and compressed and impregnated with a waxy, greenish buildup that it appears to be a continuation of the bronze "spigot" walls below it. I probably should figure on renewing it for the new installation, huh?

$185 new, eh? Why am I not surprised? "Retrofitting" this thing is looking more and more reasonable! Gonna have to get back to those back rooms in all the marine exchanges around here again soon, too...