BB33
Twas hard to come up with a name for this one, Butt Ugly, Bastard Child of Herbie and the like came to mind but I just couldn’t… Billy Gruff almost made it, it is gruff and maybe a little goat like.
In the end the working title is BB33 for a Brutally Basic craft 33 feet on the LWL including rudders.
Over the years I’ve doodled drawn and even done some preliminary design on numerous coastal cruising type proas suitable (in my mind) for bumming around the Gulf coast and the Yucatan, areas I’m familiar with.
Criteria include.
(A) Moderately spartan accommodations for two with the capability of having a couple of weekend or more guests.
(B) Easy to operate, including single handing.
(C) Shoal draft.
(D) Quick but easy performance, I don’t want to race or set records but doing 12-14 mph in a moderate breeze beats the heck out of 5 or 6.
(E) Easy and inexpensive to build, which means something I could afford to do.
Passing time is fading that last one, not sure how many more boats are left in the queue but this would be the last for sure, I think.
A lot of this is the Editors fault. First he created this forum that has fanned the flames of open discussion, criticism and creativity like nothing before it. And then he let Alexander in with Nixe and the thought snuck in “damn I could do this”. The final blow was Herbie.
A lot of my original thought about this stuff came from considering what happened if you doubled P52. Six sheets long, a full sheet high, standing room in the center, a lot of good stuff. And uh eight times as much stuff, probably more since accommodations shoot up too. Over time it was fairly easy to shrink things down to five sheets but nothing ever said “this is the one”. In the meantime rudders started to evolve (I hope) and new rig options started to appear. A lot of this stuff is going to be incorporated into P52’s successor, Nomad, and the possibility exists to go one step further.
Still it was a five sheet solution, til Herbie came along. First the extended deck really opened up the design window, and the five sheeter really started to whisper “it’ll work” to the point of making a cardboard quicky model. Hmmm looks pretty good but still it’s a lot of boat to actually build. Can a four sheet solution really do the job? Here it gets really difficult, accommodations on the one hand, performance on the other.
Down at this end of the spectrum there’s a lot of give and very little take. The one thing that bothered me accommodation wise about Herbie for my intended use was the toilet under the bunk. Sitting down and actually drawing the thing up it was possible to extend the double berths about 13” towards both ends by shaping the sheer of the hull to match the bottom. Kinda bluff looking on the screen but we gave up looking good a long time ago on this one.
Performance wise we are really on the bubble. Shooting for a design displacement of 4,000# gives us a D/L ratio of ~52:1, P52 was ~34:1. 52:1 isn’t really dog territory but it is awfully easy to add weight, far harder to remove it.
Laurent nudged me into learning the basics of Freeship which allowed some fairly quick investigation a little deeper into the guts of the design. First pass gives a hull with a displacement of 1.71 tons (3830#) at a draft of 12” and a nice fat prismatic coefficient of 0.769 (I think proas like big PC’s). Given about 600# floil displacement we are at 4400# overall, perhaps it’s doable.
Attached are screen shots of the initial Freeship model, next post will cover the cardboard model and general musings about the design.
Cheers,
Skip
To continue, guess I’ll start with design stuff and finish up with thoughts about building the thing.
First, yes the wing sails are problematical, but the question(s) should be resolved by the time this project got serious. Size looks small, but IF in fact the Ce is about double a reasonable soft sail at low speed we are looking at a loaded Bruce # of about 1.1. If all else fails there are a number of soft sail schooner rigs possible, biggest downside, they all require more work than a wingsail if they work. Supporting the wingsail mast outside the hull envelope puts the supports in line with bulkhead at berth heads and more or less lines thrust up with hydro drag. The swing radius of the tail feathers stays within the boats plan shape, simplifying anchorage and berthing.
Bidirectional end rudders to be shaped from LVL beams, slide up and down in socket attached to stempost with figure eight style hinges. Steering via push-pull poles that incorporate the up-down control lines for rudders.
Floil may want to get longer but it currently can support about 80% of design displacement and longer requires another sheet or two of ply. As it is it should support short tacking in any reasonable conditions.
Support beams attach at the top and bottom of the “cabin”, gives more separation and depth than a beam in socket approach. Fore and aft stability would come from lines from end of beams to ends of hull, also supporting some trampoline or netting. There would probably be a locker spanning between the beams at the end of the hard flooring plus acouple of storage lockers. I really like Nixie’s cockpit but also like the idea of a general use space covered at anchor and this one is really easy to build.
Building. Isn’t it a lovely model? Actually I no longer gag when looking at it, it does have a certain spartan simplicity. Model is 1:16 (1’=3/4”) if I had it to do over again it’d probably be 1:24. The model is built from a piece of white poster board about 24” x 30” equivalent to 40- 4’ x 8’ sheets of ply. No effort was made to efficiently use the material so as a first cut I think that 1,280 square feet of ply surface will do the deal. At 1.5# / sq ft (48#/ sheet) it’s 1,920# just about half our designed displacement.
Actual construction should be relatively simple, bottom of hull 1-1/8” T&G ply crossgrain, 9mm ply typically, stitch and glue most places. The flange at the top of hull should help get things lined up. Still thinking about foam sandwich core on the deck, insulation overhead to be cherished in some of the places I’d like to go. Most of the timber pieces cut from LVL beams, design properties are good and it’s relatively cost effictive.
I’m going to set this thing off to the side for a while and go back to work on the Broomstick’s wing sail, just had to get this thing out of my mind.
Skip
Skip:
Ugly is very subjective word used by people who do not fully believe form follows function. This is a design concept that hits a very specific target right on the bullseye. Bolgerian AND Fulleresque at the same time. With the potential for real world performance in excess of anything fitting the same design brief (money, effort and utility).
My concept is very similar with three sheets length and fore/aft sitting headroom (fold down seats). I’ve tried very hard to not build more boat than I will realistically use, but it is surprisingly similar. It is still too cold to build here in the garage, but I’ll start once I can get epoxy to kick.
—
Bill in Ottawa
Very VERY cool, Skip.
I like a lot of things about your build on Michael’s idea. Your connective/cockpit area is super duper cool. I-beams, no? Lets cut some holes in the webs, or CNC a nice truss in there to relieve some weight and windage. But not near the hatch, for the weather protection. The popsicle sticks feel perfect! It feels protected but not excessive. Where is the baby-buggy bimini/shelter in the cockpit? It’ll be sunny in the Yucatan!
I understand why you put some straight lines in there—volume, simplicity, sheet utilization. But those could be softened up to gain a lot aesthetically with not much loss from a volume or utilization standpoint. I’m thinking specifically of the bottom of the pod and bottom in side view, and the straight part on the bottom and at the gunwale seen from below. I’m not sure that it makes much difference in terms of performance, but it would warm up the look.
The rudders would be brilliant with a Goat Island Skiff type construction. Don’t forget to through bolt the cheeks! But I would take the pointy caps off, and make the rudders longer. That way you could lay on deck and reach most everything with your hands when things go kablooey. If your up/downhaul system took a dump, you could still easily, manually raise and lower them.
And finally it has your floating foil ama. How is that experiment going? Does it give you enough lift?
Very cool, Skip. I love the idea stealing that happens on this forum. Stealing is the currency of creative collaboration!
chris
Bill,
My next boat is a three sheeter also, aka Nomad, basic boat has been the same for some time but details keep changing (simplifying), now I’ve got to wait and see which direction the broomstick sails off in, wingsail or soft sail. Look forward to seeing your boat develop. The big difference in our three sheeters is the operating area, yours a tad chillier.
Chris,
Will need to think on some of this stuff for a few days but really appreciate the comments. Bimini’ll be there just not modeled at the moment. Beams are box beams but may be able to cut away some, though won’t really do much for windage.
Rudders may need to be longer would probably laminate an open guard at the top for a little bounceability.
Cheers,
Skip
And finally it has your floating foil ama. How is that experiment going? Does it give you enough lift?
Let me answer this one separately, Floating foil outrigger isn’t much of an experiment, it’s already worked on P52,
It’s true a deeper daggerboard type foil would have better lift/drag but at the cost of more draft, and I’ve had all the get out and push experience I need. It’s just like any other fin keel just doesn’t have a hull above it.
Skip
[/quote]
Let me answer this one separately, Floating foil outrigger isn’t much of an experiment, it’s already worked on P52,
It’s true a deeper daggerboard type foil would have better lift/drag but at the cost of more draft, and I’ve had all the get out and push experience I need. It’s just like any other fin keel just doesn’t have a hull above it.
Skip[/quote]
Its so skinny that you probably have some control of the immersion by moving weight ww/lw, no?
Its so skinny that you probably have some control of the immersion by moving weight ww/lw, no?
Yep on P52 I have even hung off the leeward side to clear some shoals while there was someone else to steer.
I’m really pleased that Herbie already has a “child”. To be honest, I hesitated to even post the design at first, because it was rather odd, so I’m glad that others see some merit, and incorporate some of the DNA into their work.
It does have a bit of the Maersk aesthetic going, but I think Bolger wouldn’t mind. Besides, the other nice thing is that if someone DID want to go for a 5, 6, 7 or more… panel cargo proa solution, it’s pretty easy to modify. It’s the wing sails - you always see those proposed for giant container ships, so somehow they fit right in.
Not to drop names or anything, but I was chatting with Jim Brown the other day (yes, I was!) and he said that it was his humble opinion that proas were the future of shipping. Not just yachting, or sailing, but shipping.
Not to drop names or anything, but I was chatting with Jim Brown the other day (yes, I was!) and he said that it was his humble opinion that proas were the future of shipping. Not just yachting, or sailing, but shipping.
Sorry a little off topic for this thread, but have to ask….. will you be writing another article containing the wisdom gleaned from that chat for those of us no so lucky? 😊
Dave.
Sorry a little off topic for this thread, but have to ask….. will you be writing another article containing the wisdom gleaned from that chat for those of us no so lucky? 😊
There’s not much to tell. He’s working on a small proa project and he asked me to keep it under wraps for now. And then he briefly mentioned his opinion that the proa would eventually become an important part of water transport. So who knows… BB33 might become a sort of proa-totype for the future. 😊
... BB33 might become a sort of proa-totype for the future. 😊
Don’t hold your breath, right now it’s just an intriguing idea to keep an old man occupied, ;-0
Skip
Looking at all of that surface area that needs fiberglassing… I wonder if this boat is a candidate for Kelsall’s KSS building, on a pre-finished table? One can buy 3mm “whiteboard” material—it’s thin micarta bonded onto masonite hardboard—for $13/sheet at the big box stores. Lay this on a base of OSB strandboard, at another $12/sheet and you could have a 4-sheet table, complete with all framing, for less than $200. Now you can lay down resin, cloth, then the plywood, all pre-cut and puzzle-jointed together. Throw plastic over it and use a shop vac to suck it down, and bang; pre-finished and pre-cut hulls, sides, decks, bulkheads.
You’d need to drill 1/8” holes on perhaps 3” centers to get the vacuum through the plywood (that’s a lot of holes!), but these get filled with resin during the layup and never need any finishing.
Chris put an idea into my head that just won’t leave; finish the inside—the entire inside—with peel-ply. This is then ready for secondary bonding where needed (filleted joints), but just left as peeled-away peel-ply everywhere else—non-slip, pre-finished, non-shiny (with some colorant in the resin if you don’t want raw plywood color).
What’s not to like?
Dave
(I wonder what would happen if you built an entire boat out of OSB strandboard??)
(I wonder what would happen if you built an entire boat out of OSB strandboard??)
I’m a fan of OSB, it’s a cost effective material for a lot of stuff, helped my son deck a sleeping loft in granddaughters bedroom last week with the stuff. Even considered it for “marine” use above the water once.
http://www.duckworksmagazine.com/02/contest2002/06/skip.htm
But I’d be very, very leery of using the stuff below the waterline or anywhere performance really mattered.
Cheers,
Skip
In response to Chris’s gentle suggestion that my preliminary Freeship model was a little uglier than need be, I went back and got things cleaned up a bit. First, my assumptions about where the edges of a four foot wide thirty two foot long sheet of plywood landed in 3D space were a little off. Second my first chine import into freeship lacked a little rigor.
Here’s what it looks like a little closer to reality. Besides clarifying the intersections and cleaning things up, the stem posts are now vertical.
Skip
(I wonder what would happen if you built an entire boat out of OSB strandboard??)
I’m a fan of OSB, it’s a cost effective material for a lot of stuff, helped my son deck a sleeping loft in granddaughters bedroom last week with the stuff. Even considered it for “marine” use above the water once.
http://www.duckworksmagazine.com/02/contest2002/06/skip.htm
But I’d be very, very leery of using the stuff below the waterline or anywhere performance really mattered.Cheers,
Skip
Dave isn’t suggesting the OSB be use for the boat - he’s using it for the underlay on the table. Cheaper than ply.
His ask about the OSB boat was an afterthought (and I sure would not do it - OSB is like Kleenex when wet).
—
Bill in Ottawa