Sweet Rhode Island Red
Thanks, Hugo.
It does seem to be coming together. I’m happy with how the rudders came out. They’re the lightest design I could come up with that would still be made in a 2 pieces (left and right) so that each half is a one sided (no flip) machining operation. The loop in the tiller is to add some cross sectional area, without adding TOO much weight. If you look at the front A arms on paralever equipped BMW motorcycles, they make lots of use of that kind of a loop.
The magic question…will it point?!?
Looking good. The rudders have an organic, neo-deco look. Actually, I guess the streamlined pod and seat supports continue that theme. I much prefer the new perforated ply seating.
Love the rudders. This whole evolution has been eye-opening. May change the way I think about rudders and proas altogether (Achilles heels, to date!)
Also love the look of the perforated platform. However, the don’t-let-it-rot fairy in me cringes at all that exposed plywood end grain. OK, sure you can encase it in epoxy and that’d work, but I wonder if there may be other possibilities? Maybe even stronger?
Seems to me that a basic traditional wood grating might do the trick. Visualize 3/8” by 2 1/4” oak flooring boards, set up to have, say, 2.5” spaces. The total structure should be very strong and with no end-grain exposed.
OK, want to keep the round perforations? Fine, same as above, but now CNC the 2.5” squares out to 3” circles (OK, “almost” circles), after assembly. You’ll still have net 1 3/4” by 3/8” strength members, two layers thick. Could make them teak if you like (I wouldn’t—I’d stick with oak myself, and just keep it oiled)
Just a thought,
Dave
Looking very good! How are you planning to fold up the rudder? A remote system maybe like my mock-up a couple of pages back or just lean in the water and pull it up by hand? Oh and is there something keeping it down in the right place?
-Thomas
Looking very good! How are you planning to fold up the rudder? A remote system maybe like my mock-up a couple of pages back or just lean in the water and pull it up by hand? Oh and is there something keeping it down in the right place?
I have and I should illustrate that. In the mean time…there will be two tethers.
One is the anti torque line for when the blade is in the water. It goes from around the base of the metal tube and up to the forward aka. It needs a bungee thingie to gather it up when it is slack; when the blade is up.
The second line is the one that folds up and holds the rudder in place. It attaches to the rudder through a hole near the aft edge of the foil, as high up as possible on the full width blade—just below the radius that scoops the rudder away above the water. If you put this line in from the windward side of the rudder, and put a stopper in it, you now have a line that retrieves and folds the rudder over. The stop is the tiller on the deck. The location of the point that the retriever line passes through at gunwale level is the sore spot. I imagine a metal ring, hovering above where the retriever hole is when the rudder is folded up. Then I attach two colinear pieces of rope to the ring between the gunwale and near aka. Like a bridal with a ring in the middle. Getting it high enough to lock it down securely is not a done deed. You could put something cantilevered off of the platform…or?
Seems to me that a basic traditional wood grating might do the trick. Visualize 3/8” by 2 1/4” oak flooring boards, set up to have, say, 2.5” spaces. The total structure should be very strong and with no end-grain exposed
Yeah! Absolutely! Its certainly a better resource yield than throwing out hundreds of plywood circles. I’m not sure its easier though. A traditional grate is dadoed so that the intersections are 1/2 thickness X and 1/2 thickness Y. Dadoing can be quick with a good jig. An even quicker way would be to just stack them up with glue in-between. 3 layers? Extra layers in critical areas? But that creates lots of voids. Ok…maybe instead of the dados, we cut little blocks to fill those voids—effectively making grated plywood…from scratch! Cut a little jig that makes it quick to drop everything in place,vac bag the whole thing and then cut the radii with a router.
Or maybe leave those voids and don’t rout and don’t worry.
But dropping a sheet of plywood onto the cnc feels easier…probably not better though.
Either way, all those holes are a pain in the ass for finishing. My outrigger seats were just varnished and I cut all the radii with a router (by hand—a table would have been better). Those routs were a bit hairy, so all that had to be sanded. With the cnc you can shave it smooth, its just more machine time.
Is Red the simplest proa? Surely not. It’s just the intersection of a lot of different ideas about simple proas from the folks on this forum. Also some Marshallese folks.
Here’s an idea. How about throwing two mast steps in the bows of Red and we can try Worsley wings in the bows; Dave Culp’s air rudders. That would be a neat experiment. You’d probably weight shift still, but only to power up or power down the aft, steering sail.
...I think.
It would be a happy day when you unbolt the pretty rudders and put them in the shed.
Seems to me that a basic traditional wood grating might do the trick. Visualize 3/8” by 2 1/4” oak flooring boards, set up to have, say, 2.5” spaces. The total structure should be very strong and with no end-grain exposed
Yeah! Absolutely! Its certainly a better resource yield than throwing out hundreds of plywood circles. I’m not sure its easier though. A traditional grate is dadoed so that the intersections are 1/2 thickness X and 1/2 thickness Y. Dadoing can be quick with a good jig. An even quicker way would be to just stack them up with glue in-between. 3 layers? Extra layers in critical areas? But that creates lots of voids. Ok…maybe instead of the dados, we cut little blocks to fill those voids—effectively making grated plywood…from scratch! Cut a little jig that makes it quick to drop everything in place,vac bag the whole thing and then cut the radii with a router.
I wasn’t thinking of dadoing, no—you halve the strength of each piece. I was visualizing a simple criss-cross 2-layer lattice, with the holes cut out on the CNC. Zap, bang, you’re done (and I wasn’t considering vacuum bagging—you’d save maybe half a tablespoon of epoxy!) Simple
OTOH, now you mention it, the finished product would have “grooves” in it; the “up” staves are all either horizontal or vertical, so not smooth. I think that looks OK, because the round cutouts (or squared-rounded, or rounded-squared, depending on how big you make the holes); anyhow, the cutouts draw the eye, not the fact or absence of grooves.
If you don’t like the grooves, then I’d favor the “drop in little blocks” approach. If you are using epoxy you don’t need any clamping, esp if you are using accurately dimensioned lumber and a good cutoff saw—so can cut to close tolerances.
I also was not thinking about routing the final grate—either the straights or the rounds. More work than is justified, I think. Then again, I’d probably get wrapped up in “minor” sanding, and wish I’d routed after all! Either way, I’d think you’re just knocking off the sharp edges, not creating a real radius. Call it 1/32 - 1/16” radius. You could do this before assembling anything, to get the straight bits rediused (two corners only), if you don’t go for the little blocks, then route or hand-radius only the round bits—or build yourself a giant countersink and go after them with that.
You need considerably less radius working in dimension lumber than you do with plywood, I guess is what I’m saying.
Is Red the simplest proa? Surely not. It’s just the intersection of a lot of different ideas about simple proas from the folks on this forum. Also some Marshallese folks.
Here’s an idea. How about throwing two mast steps in the bows of Red and we can try Worsley wings in the bows; Dave Culp’s air rudders. That would be a neat experiment. You’d probably weight shift still, but only to power up or power down the aft, steering sail.
I would say that Red goes a long way down the road towards Tertiary Design. It’s not necessary to go 100% in order to score points. 😉
As to putting experimental wings on a proa, be careful what you ask for. I’ve been sorta waiting for someone to volunteer!
Dave
As to putting experimental wings on a proa, be careful what you ask for. I’ve been sorta waiting for someone to volunteer!
I’m not sure it’s “volunteering” but I’ve got an almost finished proa and am smitten with the simple elegance of Peter Worsley’s cam. Let nature take its course, But the cambered panel staysail will get trialed first (have to have a benchmark) 😉
Did pull out a piece of 2” o.d. aluminum tubing (aka stub mast) and braced it up against the beam. Tis a little short at 53” to what I had in mind (72”) plus it’s of questionable quality, but it is on hand. Will go back and jiggle some numbers and see if I can convince myself the thing won’t fold so close to my lap.
Cheers,
Skip
The second line is the one that folds up and holds the rudder in place. It attaches to the rudder through a hole near the aft edge of the foil, as high up as possible on the full width blade—just below the radius that scoops the rudder away above the water. If you put this line in from the windward side of the rudder, and put a stopper in it, you now have a line that retrieves and folds the rudder over. The stop is the tiller on the deck. The location of the point that the retriever line passes through at gunwale level is the sore spot.
Ahh, smart. Perhaps you could have some kind of a mechanical lock on the tiller where it hits the deck instead of using the rope for this?
-Thomas
I’ve considered that, Thomas. But if I can leave one thing out, I’d rather.
The proof is in the using….
So I tried out your slat grill, Dave. I like it.
The total volume is about the same as for my perforated meranti platform, but a foot longer and a foot wider—which was the size that felt right to me in the first place. Freedom from the constraint of 4x8 sheet goods!
There are also a lot of neat things you can do to reinforce or lighten locally. I put 2 1/4’x3/8’ strips 4 3/8’ apart in a 3 layer longitudinal/transverse/longitudinal grid. Every other longitudinal bottom plank is double thickness and the ones in between get stiffener/spaces to bring them to aka level and spread the loads. Then the bow/stern ends get a longitudinal cap.
I really do like the idea of doing all the radiusing and coating on a bench, and then stacking it up in a jig with some thickened epoxy at the joints. But I’m not sure about this no clamping pressure thing. I’d at least want to put some weight on it. But then you can’t clean up the glops while the thickened epoxy is can be moved around easily.
Maybe you screw the joints down onto the table?,Then you can still get in there and clean up, or at least mush it into the gaps…
The grid design also solved my “where does the rudder uphaul lead to?” question. I lengthened some of the slats, and they lie directly above where I want to pull on the rudder.
I also opened up the opening to the pod. I think I’ll leave this open and self draining for light gear like tents and dry bags of clothes. There should be a couple good sized, watertight hatches in the floor of the cockpit for heavy stores. I think that the PT Watercraft ones are clever and clean.
But the biggest difference is the ama connection. I’ve been thinking about quick-ish set up and have come to the following concept. You make the akas. Then you cut a 1:12 tapered wedge out of the bottom surface of both ends—the vaka and ama ends. Then you mold fiberglass sleeves over the tapered parts. then you take those sleeves and glue them to the ama connectors and aka bulkheads. Now a simple lashing that keeps the aka seated in the two tapered sleeves is all that is necessary to keep the structure tight.
To set up, slot the akas into the vaka and lash lightly, slot the ama onto the akas, tighten up the whole thing, screw the platform down (6 bolts) set up the rig and splash it off of the trailer. No Scampi, but not bad for a proa.
I’m not sure if I need to taper just the bottom of the aka or the bottom and the side. I don’t want to over constrain it.
Anyway, wow, this is getting close to schematically figured out.
some more renders…sorry for the glitchy white in the ama.
I really do like the idea of doing all the radiusing and coating on a bench, and then stacking it up in a jig with some thickened epoxy at the joints. But I’m not sure about this no clamping pressure thing. I’d at least want to put some weight on it. But then you can’t clean up the glops while the thickened epoxy is can be moved around easily.
Maybe you screw the joints down onto the table?,Then you can still get in there and clean up, or at least mush it into the gaps…
Sorry I wasn’t clearer. Yes, by all means clamp the grid joins (might consider drilling them for alignment pins, or screw them to the table, but I wouldn’t want to leave metal in it permanently if I could help it). When things go into clamps in layers, they tend to get squirrelly—right after you leave the shop for a well-deserved beer. The “no clamp” bit refers only to the drop-in spacers, if you choose them. No clamping needed—or wanted, because you don’t want to drill a bunch more alignment pin holes, now do you? 😉 They still could drift, I suppose…
Dave
But the biggest difference is the ama connection. I’ve been thinking about quick-ish set up and have come to the following concept. You make the akas. Then you cut a 1:12 tapered wedge out of the bottom surface of both ends—the vaka and ama ends. Then you mold fiberglass sleeves over the tapered parts. then you take those sleeves and glue them to the ama connectors and aka bulkheads. Now a simple lashing that keeps the aka seated in the two tapered sleeves is all that is necessary to keep the structure tight.
To set up, slot the akas into the vaka and lash lightly, slot the ama onto the akas, tighten up the whole thing, screw the platform down (6 bolts) set up the rig and splash it off of the trailer. No Scampi, but not bad for a proa.
I’m not sure if I need to taper just the bottom of the aka or the bottom and the side. I don’t want to over constrain it.
You’ll be happy to know that Newick was here before. His unfortunately branded “somersault” trimaran used tapered, pyramidal ends for the beams that fit into matching tapered, pyramidal slots, the only thing required to lock them into place was lashing down the trampoline netting. Fairly typically brilliant. I think James Shanahan has some familiarity with this concept and can probably advise, once he returns to the interwebs in a few days.
I really do like the idea of doing all the radiusing and coating on a bench, and then stacking it up in a jig with some thickened epoxy at the joints. But I’m not sure about this no clamping pressure thing. I’d at least want to put some weight on it. But then you can’t clean up the glops while the thickened epoxy is can be moved around easily.
Maybe you screw the joints down onto the table?,Then you can still get in there and clean up, or at least mush it into the gaps…
Sorry I wasn’t clearer. Yes, by all means clamp the grid joins (might consider drilling them for alignment pins, or screw them to the table, but I wouldn’t want to leave metal in it permanently if I could help it). When things go into clamps in layers, they tend to get squirrelly—right after you leave the shop for a well-deserved beer. The “no clamp” bit refers only to the drop-in spacers, if you choose them. No clamping needed—or wanted, because you don’t want to drill a bunch more alignment pin holes, now do you? 😉 They still could drift, I suppose…
Dave
Hi Chris, a bit of a crazy idea…
Not sure if pratical, but could you drill these alignment pins in ALL the grid joins and bolt or revit them in a way that it allows them to just slide, so that if you pull the first and the last in oposite directions it should “un-square” it and reduce the with of the platform for transport?
It would make more or less diference, depending on how far apart you place the strips.
Cheers
hugo