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| A Work in Progress |
Rome wasn't built in a day.
-- Old saying
LUTRA Update: Building Blues and Bloom
There are two things I yammer on about:
- Small is beautiful. - E.F. Schumacher
- Curves and angles add to building time and effort. - Me
Yeesh. I should listen to myself.
We're just rounding the one year mark on what we'd estimated to be a four month project. Six months if the stars mis-aligned.
A winter build - now approaching another? - interrupted work with deep-freezing spells and general hypothermia, leaving us staring stupidly at simple tasks. Weather - exceptionally cool/cold and wet stretched from that winter, through spring to latish July, bringing mildew in its train. A series of guests (whom we thoroughly enjoyed) brought a warm spell that ended promptly with their last departure. Back to hypothermia. Our short-handed community has needs with few to step up. Our own life has chores that can't be indefinitely deferred.
It adds up to a blues riff.
But one step in front of the other. The structure is complete and we're building and tacking on gear (hatches, tabernacles, bow rollers, cleats, rails, rudder/tiller, etc.). In a week or two - barring further issues - we'll start the simple interior, then windows, then launch. we're hoping for 2025.
So we persist. We dream of returning to life at large among the islands.
We bloom.
*****
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| It's a challenge taking photos from point blank! |
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| Rowing Cockpit from Forward Longitudinal Seat/Lockers between Self-Bailing Decks Main Tabernacle at Main Bulkhead |
Longitudinal seat lockers to Leanbank/Fo'c'stle Hatch
Fore and Main Tabernacles visible
Dave,
ReplyDeleteAs you know, I've been eagerly awaiting an update, and it has not disappointed, very nice. Well done everyone on the work so far. Logistics and frostbite aside, you must be pleased with the transition from sketches and ideas, to life-size and real.
One request, I'd be keen to see view of the stern. Other than that, nothing to contribute but moral support and encouragement.
Matt
Hi Matt,
ReplyDeleteI'm hoping to add the stern view in the next days... I thought I'd wait until its got a number of parts mounted (they're built, but being oiled prior to mounting). If it drags on, I'll add a shot as-is and switch out when that set is in place.
Thanks for your interest!
Dave Z
Maybe it's the perspective but your slightly warped photo looks a LOT like a Jim Michalak Harmonica design.
ReplyDeleteIf you had not succumbed to the curvy look aside from much faster build and more buoyancy forward, what affect to the rowing would you expect?
BTW are you using the bridal veil-Tightbond system you discussed earlier?
Stay warm buddy. Hug that pretty lady for me.
Hi Michael,
DeleteHeh. That panoramic setting warps space and time.
I'm guessing that a box-barge shape would be as easy or negligably harder to row in a calm, but have more windage toward the bow... that would make it harder to row against a breeze and could take more effort to keep the head up.
However, in TRILOBYTE (16x4ft) - even with its boxy cabin - we did surprisingly well in a headwind, with little tendency to blow off.
Still, our choice in this new hull form was to draw in at the bow for presumably reduced windage.
The rockered bottom was chosen since we don't have girder furnishings in the interior, and Anke doesn't care for the undulations of a 'trampoline' bottom. The rocker adds rigidity without extra reinforcements. Some think it's a more easily driven shape than full flat, but it's a hotly contested subject.
In general, our choices prioritize other virtues than efficiency. Stability, stowage and ergonomics win out over easily driven arrangements. But we sure don't ignore efficiency, either! A motor might change that, somewhat, but not yet.
And yes, we decked LUTRA with tulle + TBIII. Looking good and has decent tread. We'll see how well it holds up.
I've passed along your hug, too. 8)
Dave Z
Your builds look more and more polished each time. This one is darn beautiful. In regards to the rockered bottom, barge bottom rowing question the youtube vids of "circlomanen"s triloboat proa sailing models were very revealing about long, thin barge hulls, rockered and straight run. In the same length and width the rockered version seemed MUCH more slippery. And given such a extreme length to width ratio it would be fascinating to see how much efficiency is lost by 90 degree side walls, with no pulling in of the bow, over the very comfy seat backs of your current version. In short, is it worth it? You'll soon see it seems! One of the few designer-builders out there now constantly refining concepts with actual working prototypes. You're the proletariat sailer champion BOMB that way, noble mon Cap'n Dave Z.. Might seem fringey now but in the seemingly approaching post oil world maybe sail barges will explode in use. Peace be wid yas boths.
ReplyDeleteHi Roberto,
DeleteThanks! That beauty is costing us, time-wise, but we're hoping it'll pay off over time (the oil finish, in particular).
RE Rockered vs Deadflat Bottoms:
The problem with comparison between two approaches is WHAT DO WE HOLD CONSTANT?
For instance, if we start with dead flat and rocker the bottom, do we hold DRAFT or DISPLACEMENT constant? Most would choose draft. The consequence is that displacement is reduced for a lighter, more easily driven hull. But... DUH... that tells us nothing useful about shape efficiency. Ditto with lots of other changes.
It's been interesting to watch Angus Rowboats (full dead flat bottoms) outrace curvy dogs in their class. Likely a combination of factors, but...
My favored barge plan (1/4 forward curve - 1/2 deadflat - 1/4 aft curve LOA) is harder to drive to hull speed (seems to top out a bit short... but complicated since we tow a shorey... rule-of-thumb is that should cost us about a knot... almost exactly our experience in ideal wind). An easier exit (less dead flat and more aft curve relative to LOA) would, I think, be faster based on historical models and input from more modern, non-barge racing hulls. BUT, on the same draft, overall displacement is reduced, especially aft, affecting carrying capacity and trim (aft crew placement, structure (e.g., Pilothouse) and cargo spaces (aft hold)), ramifying through design and intended use.
Rounding the chines, especially aft, is a BIG help, but a quantum leap in construction cost (time, effort, $$).
So - as always - it's a long list of compromises. To me, the big speed question is, how easily can a hull be driven to a high fraction of its Hullspeed (a small number for displacement vessels, no matter how we cut it)? Given that answer, what's the cost/benefit of achieving the DIFFERENTIAL in speed vs other priorities?
One of the first priorities is that the vessel must lie within our reach, or the rest is moot!
Dave Z