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30 December 2013

Raising the Roof: How High Should We Go?

The foot bone connected to the leg bone,
The leg bone connected to the knee bone,
The knee bone connected to the thigh bone,
The thigh bone connected to the back bone,
The back bone connected to the neck bone,
The neck bone connected to the head bone,
Oh, hear ye the word of the Lord!

'Zekiel saw them Dry Bones', Traditional 

Raising the Roof: How High Should We Go?

We've already seen a few ergonomic considerations flash by, without much comment. 

In plan view, bunks are laid out just-so long to accommodate folks. Standard is 6ft6in, but people are getting taller. Anke's brother's height (he can use 7ft) actually influenced our design.

Seats are thus high and yea deep. Foot room requires so much. Gangways are sized to let two squeeze or waltz by.

Last few days we've been going over the complex of head room.

Sitting headroom, to be exact, which is all we're going to have in the salon (living room). Ply dimensions yield (almost) no-brainer, standing headroom, but sitting headroom is tricky.

Note, in the following, that the cabin headroom, in TriloBoats, is completely tied to the height of hull sides (with a given amount of crown (6in)) , since there is no bilge. 

We've got to balance the following elements:
  • Construction Economy -- Four feet is too low for standard sitting headroom over standard seat heights, so the sides must be extended upward. The range of (our) possibilities runs from 4ft8in to 5ft sides. This determines the height to the inside corner of sides and deck.

    A 36ft hull is 4 1/2 sheets long (48inx8ft each). That means twice that number of strips to extend the sides upward. So nine strips. Already an ugly plywood number.

    We can get six, 8in strips out of a sheet, so we'd need a sheet and a half for 4ft8in sides.

    We can get five, 9in strips out of a sheet, so we'd need most of two sheets for 4ft9in sides.

    We can get four, 10in strips out of a sheet, so we'd spill into three sheets for 4ft10in sides, but with significant, odd leftovers.

    We can still get four, 12in strips out of a sheet, so, three sheets for 5ft, with a counter sized off-cut.

    But a sheet runs around $30, so, even if we can't use off-cuts, this isn't going to be a big consideration.
  • Seat Heights  -- 18in is standard, kitchen chair height. Lets assume the cushions will compress out to that. We don't want to play with this too much. Lowering cuts into storage, under. Gotta keep tote sizes in mind, too.
  • Crowding (Sitting) -- This is where mockups really help. If the overhead is low enough to crowd us, we slouch away from it, which is uncomfortable and downright bad for the back.
    This is one of those that can't be looked up in a book. It's subjective.
    For me, it turns out that 4ft9 sides (six inch crown) is the comfortable minimum. I'm sure I can get by with 4ft8in, but my relief is palpable when it goes up that one, measly inch.
  • Crouching (Standing) -- This is advice paraphrased, as I recall, from
    Boatowner's Sheet Anchor: A Practical Guide to Fitting Out, Upkeep, and Alteration of the Small Yacht by CARL D. LANE.
    Don't let your sitting headroom be high enough to tempt you to stand, or soon you'll develop that hang-dog feeling.
    He's referring to the bad effects of standing just out-of-line, hunched due to inadequate standing headroom. Believe me, this is a pearl of wisdom! Better to zip in and sit, with dispatch, low headroom discouraging delay.

    In our case, that rules out 5ft sides... down the centerline, the 6in crown makes 5ft6in; Anke's exact height. Crowded into a crouch.
  • Windows -- Taller the better! Furnishings push the bottom edge of the cutout to 3ft3 1/2in. The upper edge is going to be 2 1/2in from the upper corner between sides and deck (more on the whys another time). Together, the non-window portion of the sides adds up to 3ft6in.

    Looking at our extremes:
    4ft8in minus 3ft6in equals an opening of 1ft2in... tolerable.

    5ft0in minus 3ft6in equals an opening of 1ft6in... yeah, baby!
    Both are under the 2ft 'limit' (half a sheet of plexi-glass), beyond which waste gets expensive.
  • Line of Sight -- Anke, standing in the galley, would like to see forward over the deck, whose height off the bottom will be side.height + deck.thickness + crown.height + window.lip.height (the height of the lower lip of the trunk cabin windows). Her height of eye is 5ft2in.

    Deck.thickness (2 1/4in), crown.height (6in)  and window.lip.height (1 1/2in) are known, and together they equal 9 3/4in.

    Now, we're going to be raising the galley sole, to lift her eyes up and over the centerline galley window lip, but the lower the better, with 8in being about max (for other reasons for later). Let's say 8in... that raises her height of eye to 5ft10in off the bottom.

    Again, looking at our extremes:

    5ft sides + 9 3/4in = 5ft9 3/4in, so her eyes clear, but barely. Has to tippy toe for a view.

    4ft8 sides + 9 3/4in = 5ft5 3/4in... we could even drop the sole to 6in and she'd have 2 1/4in clearance.

    Room to negotiate.
  • Sheer Height -- Since the top of the off-centerboard guards will come to 2ft, the further distance to the sheer with 5ft sides is 3ft. That's a bit of a clamber. It's near my crotch height on tippy toes, but well over Anke's (2ft7in).

    At 4ft8in (4in lower than 5ft), Anke is in tippy toe range. Of course, with a 3/4in caprail, it's that much higher.

    We could add an extra, external step (especially as we age), and may have to, even if we went for the low extreme.

    And, if we have to add the step, any old height will do.
  • Windage, Thermal Volume, Hull Weight, Surface Area (Cleaning and Painting) -- These guys all agree. The lower the better. 

Sooo... we've decided to procrastinate this decision. 

We're likely to settle on 4ft9in corner headroom, aka 5ft3in centerline headroom. Low as I (the tall one) find comfortable. Or 4ft10in.

But for now we're keeping it open. 

Big windows still sound good, and may make Anke's standing on tippy toe to look over the centerline worthwhile, and she could learn to resist temptation to stand in the salon. The extra work and heating involved probably won't push us over any edge. A step up over the sheer may be inevitable, anyway.

In practical terms, that means ordering one extra sheet of plywood, to cover the 5ft option.

Big whoop.

22 December 2013

Small is Beautiful vs Bigger is Better

Small is Beautiful vs Bigger is Better

So we're looking at our T32x8 LUNA. Small(ish). Beautiful.

In Inner Space: Some Thoughts on Interior Design, I wrote about this interior layout we favor for a furnished cruiser:

Our favorite layout on 8ft beam

This diagram shows no linear dimensions. From forward, the linear allotments run:

4ft Foredeck / 6.5ft Bunk / 6.5ft Salon / 7ft Galley / 8ft Cockpit = 32ft Total

This was the layout from LUNA (AS31x8), with a bonus foot thrown into the galley. Its 20ft interior was snug and comfortable for the two of us.

But our wishlist makes it feel a little cramped...

Anke's brother (who comes sailing with us every few years, for a month or two at a time) is just a little to long to fit comfortably on the made-up dinette (6.5ft). So he likes to sleep diagonally. Which means squeezing past him on our way fore or aft. An extra 6in in the salon would straighten him out.

 The galley would benefit from yet another foot. It would allow...
  • Anke's garden on the workbench (1ft x 3ft).
  • Extended wood storage under the workbench.
  • Extended galley storage and counter space. 
None of these are critical... but an extra, extra foot would relieve the squeeze of ambition. Especially, our goal of doing more foraging / hunting / processing is more easily met with the extra counter space and elbow room. The wood storage lets us be less miserly with heat, a factor as we age. The garden will be there in any case, but it squeezes the workbench without that extra foot.

Outside, we've been happy with a (nominal) 8ft cockpit for years. But. If the yuloh is going, the other person has to squeeze around its forward end. An eight foot project (such as an oar) won't quite lie flat, so we have to fudge around. Can't carry plywood, either.

The end curves of a 32ft TriloBoat are also 8ft, which scrunches just a bit abrupt. Nothing serious, but an easier curve makes an easier driven hull.

Meanwhile, LUNA maxed out our sail plan for junk rig on masts of a comfortable height. Yet we're upping displacement over 20%. If we want to keep our SA/D ratio high, we have to go with taller masts and higher aspect ratio sails (problems with that we'll discuss later), or we have to increase boom, battens and yard. Since we don't like to overhang the hull, for handling reasons, that means we're inclined to lengthen the hull under the sail.

The T32x8 LUNA displaces about 10.5Klbs @ 1ft to 14.25Klbs @ 1.3ft. That's plenty of room to grow, but at a cost of about 1in / 1Klbs.

Soooo... lets add it up:

4ft Foredeck + 7ft Bunk + 7ft Salon + 8ft Galley = 36ft


That's a 22ft interior, slightly eased in each of its sections.

The T36x8 LUNA displaces about 12Klbs @ 1ft, with 15% ballast. This is as much as we ever hope to use, without giving up an inch of draft. And it's still a light boat, for length. If we ever need to, we could sink her down to about 16Klbs @ 1.3ft.

Just to compare, a Benford 36ft Dory displaces about 13.5Klbs @ 3.5ft (shoal option), 40% ballast. A Hess 28ft Bristol Channel Cutter displaces 14Klbs @ 5.5ft with 33% ballast.

Mmm. Waffle, waffle, waffle.

In the end, the pluses won out. The minuses don't add up to that much on such a shoal boat, and some are one-time costs. Handling is very close to comparable, and pays its way with added performance. Maintenance will be the equivalent of an extra, 4ftx8ft space. Not a happy thing, but doable. It's possible the extra elbow room will make it easier across a wider area (don't have to crawl into such tight spaces to clean or paint).

So, a T36x8 LUNA it is... we have a winner!

T36x8... We have a Winner!






27 November 2013

Baseline: The design against which all others compete

 
This is the one to beat.
(Imagine a rectangle, imposed on her extreme dimensions.)


For this reason non-rigid reference bodies are used, which are as a whole not only moving in any way whatsoever, but which also suffer alterations in form ad lib... . This non-rigid reference body... might appropriately be termed a "reference mollusc"... .

From Relativity: The Special and General Theory by Albert Einstein


BASELINE: The Design against which All Others Compete


All along, the design to beat has been some close variant of LUNA, the Bolger inspired Advanced Sharpie that was our home for a dozen years.

Any prospective candidate has to improve on her gestalt: footprint, roominess, ability, ease of construction, operation and maintenance, windows, social continuity, thermal dynamics, storage, rig possibilities, deck layouts... all of these, mushed together, embody a single, quasi-morphous reference mollusc. A baseline.

Otherwise, we'd just build her again, with the benefit of hindsight.

As we saw earlier, Curvier Dogs spike some of these qualities, vis a vis square boats, but dip in others. For the mollusc that is Anke and myself, square boats won out. Here I want to take a closer look at why we're choosing a box barge over the equivalent Advanced Sharpie.

We believe that LUNA's design is 'improved', for the gestalt of our needs, by translating the AS to a TriloBoat. We came to this conclusion by mulling the comparisons across a number of headings:


Capacity  - Profile and plan view curves are formed by cutting away from the slab formed by maxLength x maxBeam x maxDraft. These cuts remove large amounts of interior volume, squeezing interior spaces and dropping a quarter of potential displacement.

The barge, on the other hand, maintains full value in plan view, and merely cuts a wedge from the underside at each end.

For both displacement and volume, the box barge wins by a wide margin.



Ability - LUNA was nimble and fast as her rig allows. Her only vice was rounding up in heavy winds (the downside of nimble). The barge is slightly less nimble (but is harder for gusts to force into the wind) and a bit slower in a chop.

The slow-but-steady form of junk rig we favor evens the playing field. Off the wind, we're not seeing any differences, and that's how we prefer to make tracks.

I'd give a slim edge to LUNA.

NOTE: If better performance under our (slow) rig were a high priority, a Curvy Dog might possibly smoke 'em. But not by as much as one would suppose!


Ease of Construction - TriloBoats dominate on this score, being as near optimal as possible. Their large deadflat and preponderance of parallel lines and whole or even-fraction-of-sheet-materials radically simplifies construction. Good thing, as they've bartered away some other qualities to achieve it!

Of particular note is that AS, plan view curvature cuts across a section-of-cylinder deck, climbing its crown as the sides curve inboard. This complicates lofting/layout and requires more side material to accomodate the upward sweep of sheer. TriloBoats, with parallel sides, sidestep entirely. We'll revisit this when looking at TAB options.

The barge has a slight advantage in that flat pane glass (the real stuff, as opposed to flexy plastic) installs easily along the planar hull. An AS hull must be faired out to a flat landing. Ditto the guards.


Ease of Operation  - The big, rectangular decks ease operations, big-time, and the foredeck has ample room for a high-power winch. The deadflat simplifies many on-the-beach operations.

Advantage, barge, by a wide margin.


Ease of Maintanence - Box barges, tend to have larger, interior spaces which ease access for cleaning. With more surface area, however, they take proportionally more elbow grease and paint, inside and out.

This one goes to LUNA by a nose.


Everything else is a wash betwen LUNA and translation. Their rigging, layout, gear and hardware are identical.

Tot it all up, and, for us, the box barge version (I'll call TLUNA from here on out) wins hands down. LUNA's advantages are slim margin; TLUNA's are wide. Curvier Dogs would certainly gain ground if we had offshore aspirations, but we don't.

For our inshore cruising needs, sharpie beats Curvier Dogs, and barge beats sharpie.

TLUNA is the one to beat.



T32x8 LUNA aka TLUNA

*****

In a previous post, we mulled over the (FANCY) STANDARD layout, but without reference to our baseline. In fact, the baseline was always holding the fort, and I should have presented it from the git go.

Let's backtrack a bit, then, and compare TLUNA with the FANCY STANDARD (FS). Hulls are identical, so we're mainly looking at interior and superstructure considerations.


Ease of Construction - Close to a wash. Choice of window materials might sway it one way or the other, but it won't be decisive, either way.


Windows - As you may recall, those huge, glorious FS windows were ever so tempting! But with windows comes doing windows. That takes lots of water and very clean, soft rags if polycarbonate is involved (no squeegee, either). Plus, do I sound like a the kinda guy who does windows?

TLUNA has ample windows - nearly contiguous - in salon and bunk. SLACKTIDE's view is purty durn good; TLUNA's windows are the same length albeit a little less tall. But, in the PH/galley, we double down with 360deg view and again as much window length... better, even,  from the counter sitting position than the FS.
 

Still, TLUNA is ample, but the FS gains an almost unassailable lead.


Thermal dynamics - TLUNA's galley cabin is a heat chimney. Heat rises and dissapates relatively quickly. Its windows are harder to insulate; the companionway is unclosable, ruling out accidental asphyxiation, but venting heat. 


The cabin of FS has more volume (more to heat), but is a single space. Heat can circulate freely within that space, without crowding a small region of it.

I'd give the edge to FS.




The Bunk - As discussed in a previous post, the low foredeck and forward position of the FS bunk cramps its style. There are solutions, but they're not pretty.

TLUNA's bunk is positioned further aft, so is not clipped by the bow bottom curve. It has considerably better headroom, with a large hatch with good placement that doesn't interfere with deck traffic. It is fully integrated with the salon, so extends the social space and open sense of inboard spaciousness.



Solid gain for TLUNA.


Windage (related to ability) - This one is tricky. My intuition is that the FS has more. But TLUNA's decks are broken up, so turbulence may eliminate any gains. TLUNA can carry a dinghy on deck, which pretty much fills her profile in to as-much-or-more than the FS.

Being ignorant of the facts, I'd flip a coin. My guess is that it's a wash, anyway.


Rig possibilities - I'll go into these in a later post. The main point is TLUNA's shorter foredeck makes better use of the airspace above the boat... she can set more working sail than the FS.


Lateral Resistence - TLUNA can go skegs or boards, FS can ONLY go skegs (deeper draft). Of course, skegs have some advantages of their own, but at the end of the day, we prefer ultra-shoal draft.

NOTE:  I did figure out a working board system for FS, with no clunking when stowed. But it's somewhat complex to construct, in comparison to the other two, and requires antifouling inside an outboard trunk. We decided, given its novelty and remote building realities, that it was a no-go.


*****

So TLUNA, our new baseline - our mollusc. It wins out against all comers. We've narrowed the field to the point that, from here on, we'll only be considering variations within this single design framework.

Stay tuned!




21 November 2013

Those Who Live in Glass Houses

T32x8 Fancy Standard

Those Who Live in Glass Houses

When the tarps came up from Andy Stoner's MARY ELISABETH (T32x12), Anke and I nearly swooned from the view!

She's what I call the standard TriloBoat design, meaning half her length being standing head-room cabin, with end curves limited to the end quarters of hull length. This, in a standard, is achieved by sides composed of a cross half sheet over cross whole sheet (with 4ftx8ft ply sheets, that means 2ft over 4ft for a total of 6ft at the sides... overhead crown adds more). 


Very efficient of time and materials. Good living space to length ratio. Sedan-like aesthetics. And the windows... did I mention the windows?

One minor drawback of the type; being flush deck, one has to go forward over-the-top. When things get woofy, it seems a long way up and far from the axis of rotation. But all things are relative... many fine boats are 'worse'. We figure we'd get used to it, quick.

That upper, half sheet can be plexiglass. In a 32ft hull, the cabin is 16ft. Windows along each side are 2ft x 16ft huge! That doesn't count the smaller end and bunk windows!

Inspired, we designed SLACKTIDE around 2ft x 8ft windows in a 'kayak' view... sitting on the floor under low headroom solved the eye-level problem. And it has been wonderful!

So now, we're looking at the standard design in T32+x8, with mid-ships stowage in a furnished interior. 


Problem to address: their 4ft height means window lower edges are above eye level when seated in standard furnishings, built on the inside of the hull. This doesn't hurt, really, but the whole point is to relax and look around.

Andy chose to raise his dinette 10in, clearing the view from there while seated. The settee, opposite, stayed low in the hole. This worked for Andy, who was looking to sleep eight. The back of the low settee folded up and locked to make an upper bunk over the one at seat height.

Anke and I - more concerned with the view - could have raised the whole sole 10in, but that would sacrifice full standing headroom, and force up/down to the forepeak bunk. But we like the bunk area to be part of the salon social space, and, while we like to sleep on the cool side, the lower level might make it downright chilly at times.


Raise the setee? That leaves a full-headroom gangway between settee and dinnette, with views from both. Hmm. Feet are left to dangle. A fold-up footrest could work, but on 8ft, would cramp the gangway. Boo.

Well... if we lower the bottom edge of the windows 6in it solves the eyelevel problem. And it grows the windows (now 2ft6in)! Only draw-back (a considerable one) is that we can no longer use efficient half sheets of plexiglass. Some of the 1ft6in offcuts are usable, but it's gonna cost us.

But OH! To sit at the table with the mornin' cup o' mud, looking round with 360deg view through those giant windows!! I call this type (with lowered windows a fancy standard.

And another consequence. The leeboardy, off-center-boards we favor are already squeezed by a standard standard (assuming blocking the view is not an option). Lowering them reduces leverage above their fulcrum, requiring tricky engineering, both of board and hull. And, when stowed, low boards can't clear the water, so clunk in any slop. 


In SLACKTIDE, we addressed the problem with travelling boards, which roll all the way aft for stowage, clear of water and windows. But they have to pull clear of the slot and they're heavy suckers! I haven't figured out any way to get sufficient, travelling mechanical advantage to help. It won't be long before they're beyond my strength to stow. The only options would be to build them lighter, or put up with blocked windows and noise at anchor.

Skegs would be our next choice, but they double our draft. Only to two feet, but that's the difference between boots and hip-waders. And that extra foot would exclude us from manys the skinny and interesting perch along the high tide marks. Boo.

On the other hand, we don't have to handle them, 'specially as we age. They raise the bottom, when grounding, a foot proud of nasty rocks. Copper bottom plating can be much lighter, saving thousands of dollars. Hmm... there's a coupla yays to balance that boo.

One perk of the design is that, since it has flush sides (and a wet-locker arrangement that can act as a mud-room... get to that later), we could cut a door into it. It may come to pass, as we get older, that we might want to haul ashore. Diminished agility to climb in and out of the boat would likely be a big part of that decision... a sole-level entry could come in handy.

Hmm. Hmm. Nice foredeck... 8ft square!.

But the bunk has to go under it and headroom is low. There's plenty for sleeping, and enough to sit and read. But kneeling would be bad for the back, if you know what I mean. Could always limit the repetoire or take it elsewhere, but it breaks up the moment. Boo.


We prefer to sleep longitudinally, rocking side-to-side on rolly nights. Oriented so, the bottom curve competes with the foot of a full-length bunk. To get more length, the bunk has to stay high (can't lower it for more headroom).

We could live with a shorter bunk (but, alas! I'm 6ft). Or we could make the bow curve slightly more abrupt to clear the foot. Or lower (bigger bow transom). Or we can add structure for more bunk head-room, such as a pop-up hatch, but that's kludgey, blocks the view and imposes on the foredeck.
And no storage (aside from the anchor well) forward of the bunk. Boo.

And such a big foredeck involves the rig. I won't go into it deeply... main point is that it pushes the foremast aft. To fill that space, one needs a high balance junk sail or some sort of foresail arrangement. If we try an unusual rig (stays'l rig, say) we'd be pretty much committed unless we had a workable back-up. Boo.

Turns out, after months of fiddling, we could address each of these problems to the point that they were no longer boos. But not quite yays, either.

We could sleep thwartships (easy bow curve, forepeak storage vs narrower bunk, reduced bunk lockers and book-space, and some discomfort in rolly conditions). We could extend the cabin 4ft forward (excellent bunk headroom and improved mast position vs fugly appearance and increased windows (already ample, now just expensive). The skegs... erm... not first choice but call it even.

But those windows... what would we sacrifice for those??? The windows held us in dithering limbo.

What we finally decided, after months of waffling back and forth, is that - for the way we live - the fancy standard would be great in harbor vs good-but-not-great underway. Great for old age vs good-but-not-great while still up-and-at-'em. Great windows vs a handful of compromises.

So, reluctantly, we decided to abandon those wonderful windows.

Boo hoo.




I could'a been a Contendah!

19 November 2013

Footprint

Some are too small.
Many are too big.
ONE is juuuust right!



Small is beautiful.  - Leopold Kohr


Footprint

How much space do we want? Do we need? Can we manage? Each chases the other's tail. Like Goldilocks, we're looking for not too small, not too big, but juuuust right!

Anke and I lived on ZOON (ex Bolger LONG MICRO at 19ft6in x 6ft6in x 10in... ~2000lb displacement), with our dog, Scups, for two and a half happy years. Minimal galley, with all-purpose, on-the-floor living. The only complaint with the space was that our raingear hung in the bunk.

Small was beautiful!

Pros:

Easy to work -- No more than double purchase required, anywhere. We could stick out a leg, safely, to fend her off in most situations. Light anchor gear.

Easy to heat -- A tiny box stove took her to 70degF in all weathers in five minutes. Any condensation released with warm air when we opened her up for the night.

Easy to maintain -- Relatively little surface area, with few cabinets or 'tucked away' stowage.

Inexpensive -- To run, maintain, berth and, if ever necessary, to replace.


Cons:

To make a very small boat work for long, one must be a natural-born minimalist. Few possessions. Hand-to-mouth living from the land. Treading light in every way. If not, one is ever compelled to break up the drift and head for town for provisions. And the margin of safety in sustenance in case of illness or incapacity is passing fine.

Going larger works against all those pros, however. Everything takes more material, gets heavier, grows surface area and complexity. Everything costs more in time and energy. We want the benefits of increased footprint, but have to weigh them against the costs. It's easy to get crazy!

SLACKTIDE (T26x7x1 at 7300lbs displacement) got the raingear out of the bunk. We can carry enough provender and tools to stay out as long as we like, virtually indefinitely. But the galley is still tiny. Many of our older friends find sitting on the floor to be uncomfortable (will we stay limber with use, or not?). And for the long term, the foodstuffs we can carry are supplemental to only small-scale forage; handfuls of dried goods, diminutive rock cod, a jar of this or that.

So, while we dabble with minimalism, it ain't us. We want to put by some stores. We like our books and pots and pans. We want to process some big fish and game (well, salmon, halibut and deer); smoked, dried or canned. Buckets of dried greens. Vats of fermented this and that (did we mention that we're making wine?).

What we want is a SWAB (SWissArmyBoat... like the knife). One we can fold out into any number of configurations. A BOATyard, a fish / hunting / processing camp, a guerrilla garden center!  One that can carry tools of preservation and the larder gained!

LUNA (AS31ft x 8ft x 13in at 8300lbs displacement) came the closest. If we'd insulated her, and made her another 5 or so inches deeper, we'd be sailing her, yet. 


LUNA's footprint gave us a large galley, useful for indoor processing of wild foods. Her mid-ships stowage made the most of a salon-style layout (dinette/settee), and allows a dedicated bunk. Her longer hull allowed higher speeds for faster transits. She has enough stowage space (volume) to carry the tools to support living at large in the SE Alaskan archipelago.

But not the displacement.


In part, this was due to overestimating her ballast requirements (about 20%) and heavier gear required by a larger vessel, but also to loss of displacement and volume to her sharpie curves. These cut almost a quarter away from a barge on the same footprint. In fact, we sailed LUNA about 3in low on her lines... roughly a ton overloaded.

One solution is simply to increase draft (increases displacement but leaves maximum beam and length the same). But we do so love that ultra-shoal draft! Every inch is a loss of cruising opportunities, and we begrudge it.

Another is to go longer. Hmm... we might come back to this at a later date. 


Or wider. Not without leaving easy ply dimensions.

But it just so happens that a box barge on the same footprint adds a whopping third again as much volume over the AS hull! 
And SLACKTIDE showed the box barge to be a sufficient sailor for our needs (wants, schmants!).

Translating LUNA's AS31x8 shape to a T32x8 pretty much does it.

NOTE: Both are four, 8ft sheets long. The plan view curves of an AS are 32 feet, measured along the curve, but only 31ft and change, measured along the centerline. In construction terms, I consider them to be the 'same length'.


Our conclusion is that a T32x8x1, weighing in at about 10500lbs (plus a reduction to 10 to 15% ballast) gives us ample volume and sufficient displacement on a reasonably small footprint.

We got us a baseline!


06 November 2013

Want, Need, Can Manage: Core Considerations

Problem-Space Diagram


The only rules that really matter are these: what a man can do and what a man can't do.
  -- Cap'n Jack Sparrow


Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away
  -- Antoine de Saint-Exupery



Want, Need, Can Manage: Core Considerations

Design always begins with what we want

How could it be otherwise? Some vision - the azure lagoon of a South Pacific Isle, a quiet slough up Lazy River, glaciated peaks towering over wind-torn waters - some vision arises of ourselves, on-board in some place.

This vision won't be ignored. It takes over our dreams waking and asleep, urgent to make itself real.

Soon enough, it takes over our very lives! We find ourselves doodling the vision onto the margins of the morning paper, on napkins, on any odd scrap we come across. Dreamy doodles - what a friend calls 'cartoon boats'. Beautiful. Impractical. 

But, deep inside, gears are turning. 

We frown at our latest; erase here and there and redraw. This or that could never work, but this could! Hmm... we invest in some graph paper and begin to scale things out, pacing them off in our front room. We start carrying a tape measure with us, noting the dimensions of spaces, furniture, ourselves. Some of our wants clash, pull in opposite or competing directions. We weigh them and write our lists of pros and cons.

We are designing the dream.

Under melody and counter-melody of want - need starts to thump out a base-line. We need a place to sleep (hammock, cot, single berth, double, rumpus room?). We need to prepare food. We need to carry stores and gear. We need to work the rig. We focus and refine our ideas.
 
And, finally, there comes what we can (or are willing to) manage. What can we afford? What physical resources are available to us? How about temporal ones? What skills do we have, and which to acquire?

It's the dynamic tension between these three that makes up most of design. In the Problem-Space Diagram (above), Each corner represents a limit: maximum want, minimum need, maximum ability to manage. A particular design is a point within the 'space' created by these three attractors.

 If you plotted successive solutions, you'd likely see that point wander around. Our paths through this space often loop, blooming from need toward want, then collapsing abruptly back toward need. Occasional spiky forays toward the higher end of what we can manage, too.

Eventually, this tendency to wander settles down. It starts to tread in very tight circles as the big picture settles down to details within it. Of course, some minor detail can blow a whole design and set us back on our peripatetic course. 

But we narrow in.




*****

Anke and I want the usual, huge on the inside, small on the outside. 

We sail year-round on rough waters, without an engine, so we like a simple form of junk rig and shoal draft (both are great safety factors). We have to be able to work it as we age, so long as we remain reasonably healthy.

We carry a lot of food (a year's supply to keep us out as long as we want), gear (anchor gear, jacks, clothing, books and tools). We want to add some collapsible field kitchen gear, SWAB style (SWissArmyBoat) and be able to carry several cases of canned goods. We'd love to be able to mount a winch big enough to haul us above the tideline.

We both love to cook, entertain and slug a-bed.

Budget is a major factor, for us. We only want to put so much energy into the boat, be it earning the money for it, putting it together or maintaining it. We don't want to skimp, but neither wish to be lavish.

Economy and hull shape considerations are complicated by our strong preference for copper-plated bottoms. While we believe the copper pays for itself, it's a hefty initial outlay. And, being sheet material, its inclusion constrains hull shapes.

Our current boat, SLACKTIDE (T26x7), meets our needs, and then some. We're building to push closer toward satisfying our wants. Fortunately (for us), we're simple folk, and many of our wants stick close to the need line. Generally speaking, we're looking for a minimum solution, and are not tempted by maxima.

But. There is that pesky issue of efficiency-to-windward.

When we have a schedule to meet (way more often than we'd like), we find ourselves pushing 'uphill', sailing against the wind and working the tides. Our strategy has been get there ASAP and play around at that end, if early arriven. But hoo-boy! Do we sometimes wish we could slice our way into it!!

Four solutions (which can be applied seperately or together):
  1. Ditch our obligations -- Easier said than done... family, guests, work, bureaucracy. 
  2. Windward Rig -- Trade simplicity, economy and quick-reef for improved efficiency.
  3. Longer WL -- Increased WaterLine = higher HullSpeed for a more easily driven hull.
  4. Curvi(er) Dog Hull -- Improved hydrodynamic efficiency relative to the box barge.
First two are non-starters, for us. The rig is sometimes tempting, but the simple junk rig satisfies our needs like no other (more on this later).

A longer boat is a consequence of our expanded wish-list. Come what may, our hullspeed is going up. So this will be more of a tipping factor between solutions competing for other reasons.

Curvier Dogs, eh? We've got the skills and the means...

 In coming posts, we'll take a look at some of our contenders.

Considering Curvier Dogs

Phil Bolger's ROMP... one Ideal Hullform.


Baby, you can't love just one,
Baby, you can't love just one.
You can't love just one and have any fun,
Baby, you can't love just one!
  -- New River Train by the Monroes


Considering Curvier Dogs

Despite going to great lengths to avoid curves in TriloBoats (slogan: Avast, ye Curvy Dogs!), I love 'em! 

Why curves? They tend to improve hydrodynamics, reducing drag and turbulence so that the hull is easier to drive (this is the one that counts, especially to windward). Curvy surfaces are stiffer than flat ones, so require less structural support. And they're oh-so pretty!

Why not curves? On a given footprint, they carve volume and displacement from the hull, and deck area. The only way to regain that displacement is to go longer, wider or deeper, upping initial costs and long-term maintenance. And the curvier a hull, the harder it is to copper and/or insulate with sheet materials. The further storage areas vary from rectilinear, the more problematic they become. The harder it is to jack, block and roll.

To pay their way, relative to boxier hulls, curves have to overcome those why nots for a clear, net gain.

 In our case, since we're practically married to dumbed-down versions of the junk rig, the prime advantage of curves (speed to windward) is moot. A slow rig won't be helped much by a fast hull. As curves are inherently more costly ($, time and energy), they push much harder against our low budget ceiling. And in a bad chance, should we lose the boat, smaller investments are easier to walk away from.

But it's worth a look! 

There are a few ways to approach hullforms (I'll defer types such as sharpie, dory, barge, etc. for later):
  • By section -- V-, U-, Y-, wineglass, multichine, flared, square, etc..
  • By construction method-- carvel, lapstrake, strip-plank, sheet plank, molded, quick-molded, etc..
Hmm... let's try a process of elimination by applying a filter:  

High EROEI (Energy Returned On Energy Invested) + ultra-shoal draft+ copper plate possible. 

Survivors are sections U-, flared and square. Construction methods strip plank, sheet plank, quick-molded. These are relatively quick and generally less expensive to construct.

 *****

I started this post with the lines drawing of Phil Bolger's ROMP. Her hull form is one I consider to be near ideal for an ideal world. One with soft bottoms and/or expansive, deep harbors and low dock fees.

Descended from Thames River Barges, it retains their square mid-section, so load carrying and form stability are near maximum. But the hard chines have been rounded to a severe U, eliminating cross- and near-chine turbulence, and the ends are drawn out fine for improved hydrodynamics (read speed).  

This hullform is one slippery devil! 

The strike against her is that she is not easily copper-plated. Thinner sheets can be stripped and applied in the traditional manner, But heavier ones will not follow her curves without planishing, and overlapping strips are time-consuming and create drag. If one did manage to plate the deadflat area, the transition to thinner, upper sheets would make the latter vulnerable to rocks on grounding.

There's also the problem of lofting. Lofting takes considerable time, and - more critical in our case - a lofting surface. A large, smooth, covered floor, available for an extended period, is hard to come by in our life.

Bolger went on to develop the ST. VALERIE, and later the VOLUNTEER hullforms. These each have a rockered, transversely flat plate. SV's sections are similar to ROMP's - essentially U-section, rounded at the chines). 

VOLUNTEER, on the other hand, is dory section, with sides slightly rounded in section plan. Getting warmer! The bottom plate is easily armored, and the sides quickly pull up and away from dangerous rocks. Still has to be lofted...

Hmm.

Meanwhile another thread has been working up through my id. The Master Curve Method produces a hull from a single master curve. Lofting is limited to this curve, laid out full-sized, which is then used to lay out frames to be located on stations.

And, if there is a deadflat in this hull, it can be arranged such that the sections over the deadflat are identical... all their frames can be laid out once and copied. And over the deadflat, all waterlines and buttocks run parallel, so no spiling!

******





So I worked up a cartoon. 

Don't worry about understanding all the scribble... it never reached the 'fair copy' stage, nor is the design anywhere beyond 'first stab'. Suffice it to say that this hullform could be quickly laid out and strip planked cove-and-bead (easy curves allow thick, red cedar planking for passable insulation). It can be quick molded over,hybrid copper plated (and relatively cheaply compared to a box barge!) and topsides h painted or simply oiled to finish.

Problems are that, to make up displacement on a given footprint, it must have much greater draft, relative to square sections. Deadrise, low in the hull mean that a raised sole must be added to clear furnishings, increasing work and weight, reducing headroom and/or increasing freeboard/windage.

And it's going to heel a lot more than we're used to, and/or take more ballast to make up for lost form stability.

Emm. Er... (stretch this out over months, with relapses)....

Nope. 

And ditto for the trimaran(!) designed along similar lines (I'll spare you the reasons). So much for our best shot at a truly Curvy Dog.

*****

Sharpie / Dories / Scows (less -boxy types)? Great ones out there. Culler, Bolger, Colvin, Parker, Benford, Roberts, Kirby, MacNaughton. I can even lay out these types so that lofting is held to a manageable minimum.

But they carve away a lot of displacement and interior volume with flare, plan and profile curvature. To get the displacement we would like, we have to deepen the draft or go with a wider and/or longer hull.

We could square up the mid-sections. That would increase displacement, form stability and efficient storage. But on any reasonable LengthsOverAll  - flaring out toward the ends - we blunt the waterlines, trading the type virtues with less in return. Again, the only alternative is to lengthen the hull... this works beautifully, but we end up with more boat than we want to handle.

Nope.

*****

Another Bolgeresque Advanced Sharpie (as was LUNA)? Square sections, copper plate enabled, great handling. Do have to increase the draft, but...

Bottom line, LUNA wasn't much better to windward than SLACKTIDE, if at all (under dumbed-down Junk Rig. Having sailed both, extensively, confirms my feeling that a fast hull is no more efficient than the rig driving it.

But she was a lot harder to build, and the curves (on 31ft) squeezed us.

Nope.

*****

Over the course of time, miscellaneous counterpoints accumulated, over time, and chipped away at curves' already imperiled EROEI.
  • Pointy bows reduce the working foredeck area. Ditto aft, and, since the sides are not parallel, we lose some perks (for another time).
  • The extremely large windows we've come to favor don't fit as well to some curves, and glass is not an option. It's harder install the interior and components against curved surfaces.
  • Curves create triangular or trapezoidal storage spaces, which are awkward and often hard to clean.
  • It's easy to cover exposed edges between copper sheets if they meet in plane or at 90deg... not otherwise (short of brazing or welding). 
Add it all up?

Nope.

*****

So our curvier candidates slowly fell by the wayside. Every boat mentioned is a wonderful type that works well in many situations (most, even), returning lasting value for the energies invested. 

But for us - where we sail and how - they just don't justify their costs.

05 November 2013

Decisions, Decisions

SLACKTIDE (T26x7), our current home, sweet home

Decisions, Decisions


Keep a clean mind... change it often!
  -- Cap'n Billy's Whizbag

A foolish consistency is the hobgoblin of little minds!
  -- Ralph Waldo Emerson 


Anke and I have been living aboard for about 25 years. We've learned a lot in these years about ourselves, life on the water and how we like to live.

So you'd think this would be easy!

By this, I mean deciding on what form our final boat should take. But no. We waffle; we back-track; we renege; we head off down blind leads at full trot.

Here, I'll be writing about as much of the process as seems worth sharing. It's pretty individual, but many potential builders go through similar throes. Maybe sharing will help?

One thing; the process of finding out what one wants, needs and can manage is time-consuming. It is generally a lot of fun, but can be frustrating. Everything in design is trade-off and compromise. If we don't accept that, frustration will outweigh the joy.

My advice is to stick with it. Work it and polish it until all the jagged edges are worn smooth; until each bit pulls together as a single, integrated whole. When the whole finally emerges, it will be worth it!

*****

Why a final boat?

Well, we're not getting any younger. The physical and economic resources we can muster to build are likely to dwindle in the coming years. If we have a shot, there's no time like the present.


What's wrong with the boat you've got?

We built SLACKTIDE (T26x7) about six years ago as a proof-of-concept for a liveaboard, sailing box barge... something we could live aboard indefinitely, if we had to, but limited in size in case she didn't work out. 

As such, she's small, and laid out as a camper-cruiser, like sitting/kneeling in a luxurious tent. We figured we had roughly a decade before the lack of furniture became a challenge. And her small capacity means we can't carry some of the field kitchen gear or liquid goods we'd like (more on that later).

Her box barge hullform exceeded all our expectations. 

The box barge, in our opinion is a truly viable option for liveaboard sailors. Not for everyone, mind you, nor all waters. But they get us where we're going in comfort and a certain, rugged style.

It made the list!


Why your own design? Why build your own?

We grow through DIY, in knowledge and skill. DIY empowers us.

In design, we know ourselves better than any other, no matter how able and willing... one size fits us - not all, or most. And in finding our way through the myriad options, we come to know ourselves better, yet.

 In construction, we acquire skills that will last a lifetime, and see us and our vessel through thick and thin. On that far and perilous shore, we have a fighting chance.

We partner and understand our own creations in ways that cannot be bought. We shape ourselves, as much as we shape them. In that shaping, we and the entities we bring to life are joined.

Our boat is shelter. Transportation. A Tool. A partner. Pretty fundamental stuff. She (or he, as the case may be) watches over us as we sleep, saves our lives by 'living through the gale'. Every moment, she enfolds us within her hull, separating us from the cold abyss.

DIY is the first act of love, in all that follows.
 

So what are you going to build?

Ah. 




[As it turns out, we've got a pretty good idea (stable this last week)... but patience, my friends!]
 

About Me

My photo
Anke and I live aboard SLACKTIDE, our T26x7 ketch. We sail by wind, tide and muscle in the waters of mid- to northern Southeast Alaska. We try to maximize the joys of life, and minimize the chores. ........ We live between the communities of SE Alaska, but drop in to visit with friends. Lately, we've worked, every other winter, care-taking Baranof Wilderness Lodge in Warmsprings Bay. This has given us a window on Web. ........ We're working toward a subsistence lifestyle, somewhat impeded by addictions to coffee, chocolate and cheese. ........ We think TEOTWAWKI is looming, and while we won't be ready, we'd at least like comfortable seats.