Herbie the Volkscruiser Proa
Hi Skip,
Really like the double hinge. I guess it’ll need something to apply a force to keep them closed up and stop them doing this…
Probably, that’s why I commented on adding elastic in the original post, on the other hand, the forward rudder is going to be pressed back against the bulkhead and the aft operating rudder “might” benefit from a little gap. Hard to say at this point, will fiddle around with geometry on Nomad and wait til I’ve learned a little bit from the Broomstick (which hits the water tomorrow!!!!!!, finally).
Cheers,
Skip
In order to hinge the trunk from its fore or aft inboard corner, we need to move the average center of the whole thing away from the hull—and this is a loaded board, pushing hard in the other direction. On the one hand, it’s going to have a strong “self-centering” feature, analogous to adding caster to a car wheel (Hey, maybe we don’t need no stinkin’ shunting boards!) but at the same time, it’s going to require some significant force to turn these rudders. Too much? Dunno.
Dave
I think, but am not certain, that the ‘caster’ action can be avoided by having the effective center-of-rotation of the foil at its center-of-lift. This could be achieved by using a large radius for the contacting surfaces of the rolling hinge. This will also result in a larger fore-and-aft motion of the trunk as it is steered. The front rudder will travel in the opposite sense to the rear rudder so the slot in the bridle will need to be longer.
the Broomstick (which hits the water tomorrow!!!!!!, finally).
Mole trembles with excitement and anticipation! (sorry, reading The Wind in the Willows this week).
I think, but am not certain, that the ‘caster’ action can be avoided by having the effective center-of-rotation of the foil at its center-of-lift. This could be achieved by using a large radius for the contacting surfaces of the rolling hinge. This will also result in a larger fore-and-aft motion of the trunk as it is steered. The front rudder will travel in the opposite sense to the rear rudder so the slot in the bridle will need to be longer.
Hmmm, I was substantially wrong in my post. Yours fixes it some, but I still think the Jacob’s ladder thing won’t work on an “articulated trunk” scheme such as we’re discussing.
If only the caster action were as I described it! Then your change could be used to give it more or less force by altering the radius of the block. Truth be told, though, the caster action is positive when you turn the board one way (wants to return to zero) and negative in the other (Will immediately over-balance with a vengance, break your arm then beat you to death with the tiller stub.) I don’t mean when you shunt, all you need to do is push the tiller over a few degrees off center! One way self centers and the other breaks your arm.
OTOH, the ‘ladder will work fine as skip drew it—to articulate the hull. It may stretch away from the hull as you say, but not as you sketched it, I’m pretty sure. The ribbons don’t run as you drew them, they run like I show, below. The stretch in the ribbons, thus the gap between hull piece,s can be kept to small tolerances, but only if 1) you pre-tension them and 2) they are very low stretch—like Spectra. It would also help, this time with wear, if the edges of the hull pieces are rounded a bit, so a half inch or so of the ribbon will flex on actuation, rather than the tiny amount if the joint is square. Of course, this chamfering will introduce a drag source itself…
I have an idea for a way to do this with just a narrow rudder and narrow sternpost, plus a couple of spreader-type outriggers, but it hasn’t crystalized in my pointy bean just yet. If I can get past the drag of the spreaders, this could allow the rudder to flip over 180 degrees—some distance from the hull—and either be locked at 180 degrees, or allowed to trail along without setting AoA. More later.
Dave
Yup, my bad - the ribbons have to be crossed.
oops
I was looking at the CLC site, lusting over Madness, and (more realistically) looking to see which kayak I want to build, when I saw this lovely new design John Harris has of a rowing/sailing micro cruiser. Obviously it’s smaller and it’s not a proa. but might there be some ideas here that could be applied to Herbie or BB33?
Looks like a good fit for completing the Everglades Challenge and raid type events. It won’t win against a multihull in any wind, but it will be easier to keep moving in a dead calm. It’s thin water genetics will open up a lot of cruising territory.
I kind of wonder why not a couple feet longer where you could get two centreline tandem single berths like a Newick Tremolino? I know only one person can sleep at a time if you are keeping watches, but it won’t be an easy sell to couples, except people used to a Matt Layden style microcruiser (i.e. Paradox). Unlike kayaks you won’t have a his and hers pair of these in the driveway.
I have to admire John Harris, he’s prolific and rather than just draw designs that never get built, he follows the Field of Dreams method and subscribes to the ideology “If I built it they will come”.
He’s probably right and the people who would never consider sailing a proa may get excited with something like this. It is pretty, embodies traditional sensible Nordic good looks and the general public will cluster around it you pull up to a beach. Sad truth is that they’ll sell 20 of these to people for every one Madness, although Madness will measurably better at everything except rowing and impressing the yacht club snobs. He’s been advertising the prototype Madness for under $40K with trailer, motor and ready to sail. I wish I had the cash burning a hole in my pocket and no mortgage to be a buzz kill. What a deal!
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Bill in Ottawa
I was looking at the CLC site, lusting over Madness, and (more realistically) looking to see which kayak I want to build, when I saw this lovely new design John Harris has of a rowing/sailing micro cruiser. Obviously it’s smaller and it’s not a proa. but might there be some ideas here that could be applied to Herbie or BB33?
John Harris certainly has the touch, the Faering is a lovely boat and if I was a of a monohull mind I’d look real hard at either building the thing or more likely making a strip planked imitation.
Proawise, it’s more Nomad like both size and design brief.
Cheers,
Skip
I saw that lovely design as well and I couldn’t help but think the only thing it lacks is an outrigger. 😉
But seriously, I think this design was a commission, so it doesn’t have to be a “best seller”. Same with Madness really, John’s own commission. I’m just so happy that CLC makes these designs public, because otherwise I’d have to settle for the SUP.
I like much the general idea and design of the hull. It is a good form and It is spacious.
For rudders, it’s just a technical problem, there is always a solution.
Now I think it will not be easy to reduce mainsail. With bad weather, this maneuver is dangerous to furl the sail.
It may be useful to refocus the mast step for easy maneuvering.
I dont no if it’s simply for you to understand my english???
Your English is fine, Ricco, thank you for commenting. Yes, others have also suggested that a single central mast would be safer to work.
I like much the general idea and design of the hull. It is a good form and It is spacious.
For rudders, it’s just a technical problem, there is always a solution.
Now I think it will not be easy to reduce mainsail. With bad weather, this maneuver is dangerous to furl the sail.
It may be useful to refocus the mast step for easy maneuvering.
I dont no if it’s simply for you to understand my english???
Lugsails like this aren’t too tough to work with. Matt Layden has got working roller reefing systems figured out for this style of lugsail - rolling up the boom and re-setting the halyard. The URL I’ve linked to is a google search result that gives you a great place to start looking at his work.
In the worst case you can rig a brailing line from the boom clew to the masthead to immediately reduce and un-power this kind of rig. I would not discount a standing lug rig for furling. It has been around a lot longer than Marconi rigs.
Every reefing scenario comes down to one issue - if you reef early and when you should, you should be able to avoid trouble.
I’m pretty far down the road on a twin masted design like Herbie (albeit smaller) and the storm reefing scenario I’ve envisioned is bringing down both main and mizzen sails and rigging a storm jib from the top of one mast to the foot of the other. Small enough that tacking (instead of shunting) is possible and safe. <= Forty square feet of storm jib would be able to drive the boat to windward and not challenge boat stability on either Atlantic (ama to leeward) or Pacific (ama to windward) tacks.
Your English is fine. Welcome! Bienvenue! Willkommen! Bienvenido!
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Bill in Ottawa
like the sails, a good solution if you must have two masts on a cruiser. i have noticed that the s. china fishing junks had much more lead at the foot than at the throat of their sails. i wonder if this is done to bring the ce closer to the mast? if so, worth emulating. to my inexperienced eye, the only weakness of herbie is the liklihood of too much weather helm, and reducing sheet load will help there.
hope you build something like herbie, simple, cheap and safe cruising proas are in insufficient numbers.
regards, al loomis
Welcome to the forum, Al 😊