Ring frames in trad. construction?

[Seth Wood]

Can someone help me understand what ring frames are? From what I've read, they appear to be somewhere between structural bulkheads and a single frame-floor-deckbeam structure, usually at the mast.

By this definition, wouldn't most floor-frames-deckbeam structures qualify as ring frames? Or should they be made even more rigid with knees or sheer clamps?

If the ring frame is laminated and epoxied, does this render it unsuitable for traditional plank-on-frame construction?

If so, what is the best way to build a ring frame in a plank-on-frame boat? Is it just, as I'm guessing, reinforcing with sheer clamps or hanging knees, or is there more to it?

[Dave Fleming]

**>** Indicates the start of my reply.

Can someone help me understand what ring frames are? From what I've read, they appear to be somewhere between structural bulkheads and a single frame-floor-deckbeam structure, usually at the mast.
>I will take a stab at this one but one BIG caveat. I have never to the best of my recollection seen nor worked on such a construction feature.

By this definition, wouldn't most floor-frames-deckbeam structures qualify as ring frames? Or should they be made even more rigid with knees or sheer clamps?
> I understand Ring Frames to be purpose constructed as a singular homogenous unit.
Something akin to small craft construction seen in skin boats or kayaks etc..

If the ring frame is laminated and epoxied, does this render it unsuitable for traditional plank-on-frame construction?
> Don't see why it would as long as the materials and the dimensions fit the vessel.
BUT,you are adding a very rigid member in a type of construction where all the parts have a degree of flexibility THAT might give you problems down the road.
Example: Think of a 'hard spot' in a 'clorox bottle' aka feeberglaz vessel. The spot on the exterior of the hull which telegraphs the location of a structural bulkhead from inside to outside the hull. I believe the way around such is a thin layer of some foam like material between the bulkhead and the actual skin of the boat. With the foam being able to compress and absorb the strain of the juncture of the skin and bulkhead.

If so, what is the best way to build a ring frame in a plank-on-frame boat? Is it just, as I'm guessing, reinforcing with sheer clamps or hanging knees, or is there more to it?
> A well designed Traditional Carvel Planked, Sawn or Steam Bent Frame vessel "unless" specifically designed to use what you are calling a ring frame should not need one. If there is something you have left out of the details of your question, such as particular loads or needs then it would behoove you to inform us of that.

Again, I cannot stress this point enough, ***yeah yeah yeah dave ya sound like a school teacher with this mantra*** but, without as much detail as possible how can one expect decent answers??

PAX

[Seth Wood]

Thanks for the reply, Dave. I have no more details because I'm not thinking of anything in specific, just boat construction in general.

But say you had a plank-on-frame sailboat, 30-40' or so. Cast bronze floors and cast bronze "knees" between the frames (double-sawn) and the deck beams (cambered, laminated). No sheer clamp, as the load is taken by those knees. Is this a "ring frame" or just smart strong construction?

Or consider the same vessel, with a thick structural bulkhead at the mast partners, bolted through deck beams, frames and floor, made of, say, 3 layers of 1/2x6" wood planks, glued diagonally, with an opening in the middle big enough to step through. Same question again: is this a ring frame or just smart strong construction?

I'm guessing that it's just smart construction, whatever it's called. It seems very strong but perhaps not necessary at every frame.

[Thad]

I think a true ringframe would have to be metal in a traditional construction boat. In a small boat I can almost imagine bending a timber continuous around the inside of the hull, though at the deck you would need to run inside a knee. Otherwise, the metal "ringframe" would have to be fabricated to take the place of the frame-floor-beam structure that would otherwise be there or be fabricated to reinforce the frame-floor-beam structure that is there (preferably throughbolted), with the chainplates integrally connected with the "ringframe". Glass or other resin structures could be made up like a ringframe, but I think they would invite strength issues in the hull structure they are supposed to support. Traditional construction uses hanging knees, blocking, floors, strong timbers and bolts to develop a powerful structure more flexible than the "ringframe".

[Dave Fleming]

">" indicates my answers.

Thanks for the reply, Dave. I have no more details because I'm not thinking of anything in specific, just boat construction in general.
> Oh I see, just shootin' the breeze so to speak, eh?
<insert big grin here>

But say you had a plank-on-frame sailboat, 30-40' or so. Cast bronze floors and cast bronze "knees" between the frames (double-sawn) and the deck beams (cambered, laminated). No sheer clamp, as the load is taken by those knees. Is this a "ring frame" or just smart strong construction?
>Cast Bronze Knees 'between' the frames? Hanging knees are on the frames and connected to them and the above deck beam, IIRC.

Or consider the same vessel, with a thick structural bulkhead at the mast partners, bolted through deck beams, frames and floor, made of, say, 3 layers of 1/2x6" wood planks, glued diagonally, with an opening in the middle big enough to step through. Same question again: is this a ring frame or just smart strong construction?
> Just hell for stout construction, IMOOP,that is. As I see a 'Ring Frame', a bulkhead is not necessarily included.

I'm guessing that it's just smart construction, whatever it's called. It seems very strong but perhaps not necessary at every frame.
> No I can't see why one should be needed unless you are building a 60 gun warship!

[Bob Cleek]

A continuous frame-deckbeam-floor circular unit does not a "ring frame" make. I suppose you could call such a member a "ring frame," but in "traditional" construction, it isn't. It's just a "one piece" frame and deckbeam unit, and fine for laminated construction, if you want to go to the trouble to build a jig for every damn frame in the boat.

The term "ring frame" was, as shouldn't be too much of a surprise, a Herreshoff invention, or so LFH claimed. (Bless his heart, I often think that he somewhat exaggerated claims of Nathaniel's "inventions," but what the heck... he was entitled.) The Herreshoffs employed ring frames in the construction of a few longitudinally framed racing vessels. This was a technique that permitted relatively light weight hulls for racing purposes (but apparently, as racers were wont to be back then, not a long lasting construction method.) The hull was framed by cutting out ring frames which were very narrow on the sided dimension and very deep on the molded dimension. (Today, they could be cut out of a sheet of plywood.) These then had notches let into the outside edges so skinny stringers running run fore and aft, like permanent ribbands, could be set in them. The boat was then double or triple planked up on the whole lightweight frame. This was the same sort of framing that was later used on the fuselages of the old cloth covered airplanes, for the same weight saving reasons, and identical to many canvas and skin covered kayaks. In today's construction idiom, this might be a very good way to construct an epoxy cold molded hull, with the longitudinally framed shape serving as the mold for the lay up. However, LFH wrote that he came to disfavor this construction technique because each frame and its beveled notches had to be developed and meticulously picked up off the loft floor for it all to come out right, making it very expensive labor-wise.

[ 02-11-2003, 04:43 PM: Message edited by: Bob Cleek ]

[JimConlin]

Is this what you're thnking??
http://www.personal.psu.edu/faculty/d/r/drf6/s8.jpg

L. Francis Herreshoff, designer.

[Seth Wood]

Thanks for all the replies. Yes, I'm afraid I don't have a particular boat in mind, just shootin' the breeze. Pretty boat, Jim C, those seem to be what I was thinking. I think that clears it up well, Bob,, great description.

Seems like the term "ring frame" is less suited to traditional construction than to glued strip, diagonal layers, smaller kayaks, ply daysailers, etc....than it is to plank-on-frame vessels, which can get that same kind of strength from hanging knees-deck beams-frames-floor units, or well-constructed structural bulkheads. After all, expand those Herreshoff ring frames out a bit and you've got a structural bulkhead....

Thanks again, all.

[Bob Cleek]

Ah, yes, Jim... a picture is worth a thousand words! LOL That's what I meant!

As for the framing technique on plank-on-frame vessels, it won't work because you don't have enough meat to fasten your planks to. Herreshoff's double and triple planked them, which was for its time, the same thing as our WEST System cold molding. Herreshoff put muslin and white lead between the layers of wood and then fastened it all through on both sides with little screws, since they didn't have epoxy in those days.

[JimConlin]

I didn't give full atribution.

There's more Here (http://www.personal.psu.edu/faculty/d/r/drf6/gjoa.html)

I just stumbled across it. I'm in love.
Jim