T26x7 (Slacktide) FAQ Page


Anke and I have just launched our new home, Slacktide, which is a T26x7. As of this writing (January 2009) we have yet to furnish the interior and fit her out for sail. We hope to be sailing by May or June of 2009. Please be aware that many concepts in this design are as yet untried (see below)—we hope to have put them to the test by the end of summer, 2009. Stay tuned!

Here's a quick run-down of reasons for building Slacktide to replace Luna (31'x8' Advanced Sharpie):

  • Insulation (built Luna without... like, helLO? We live in Alaska?)
  • Containerized storage (see below)
  • Settling into a smaller configuration (Luna allowed too much stuff to accumulate)
  • Bigger windows with good view from the sleeping area (to ease checking anchor ranges)
  • Separation of water-tight compartments (redundant positive buoyancy)
  • Filleted interior angles (for ease of cleaning)
  • Hard, dynel/epoxy-over-plywood decks (vs. Luna's soft latex/glass-over-cedar)
  • Transom space for a Seacycle Pedal Unit (see below)
  • Slacktide will allow us to gain first-hand experience sailing a TriloBoat.

Frequently Asked Questions

Aren’t those weird numbers for TriloBoats?
What are her other numbers?
What materials did you use?
How long did it take you?
How much did it cost?
Why sheath a boat in copper?
What was your intended purpose with this design?
How is Slacktide laid out?
How are the decks laid out?
How are you going to rig her?
How about auxiliary power?
What special gear will you be carrying?
What elements are untried, and why are you trying them?
So you've launched her—what are your initial impressions?

Aren’t those weird numbers for TriloBoats?

Yes. Slacktide is out-of-formula in several ways.

First, the hull sides are only four feet (one sheet) tall, vs. six feet (one-and-a-half sheets—the TriloBoat formula standard). This reduces windage considerably at the cost of sitting-headroom-only throughout the cabin. A consequence is that, as no half-sheet upper panels are used, they can’t be canted inboard to provide the slack necessary to crown the deck. The T26x8 variation (which uses a full, thwartship sheet of ply for the hull), the cabin deck requires the next-size-up ply or extra work piecing sheets together to cover the crown and eaves.

By reducing the beam to 7 feet, we improve the length/beam ratio, still maintain a standard bunklength athwartships, shorten the unsupported bottom span and gain a foot of slack for the deck. This is more than enough for Slacktide's rather extreme deck crown, and we used the extra for an overhang (more on that later). Incidentally, she’s well within trailering limits, though rather heavy. The downside is that every thwartship hull piece required layout and cutting, wasting time and some material (much of the waste material can be used as framing or for drawers).

Originally, we were going to build 24 feet (three sheets) long, but decided (given our party-animal natures) to add two feet to the cockpit. This requires one extra butt join per side and a tad more material, but is relatively harmless, construction-wise, and further improves length / beam. If ten foot sheets are available, you could eliminate the extra scarf (using two eight- and one ten foot sheets to total 26 feet).

What are her other numbers?

Our target draft is 10 inches for 6720 lbs of displacement. We can load to the 13 inch mark, for 8736 lbs displaced (after that, we risk dipping a corner of the bow transom when heeled). Interior beam is 6 ft 8 in (after insulation) and 4 ft 9 in of headroom along the cabin mid-line, 6 ft 6 in in the scuttle.

What materials did you use?

The hull sides and foredeck, as well as all bulkheads are ½ inch AC fir-like plywood, the bottom is 1 1/4 inch (½ + 3/4 inch ply) sheathed with 1/16th inch copper plate. The aft deck is 3/4 inch ply. The mid-deck is a layer of ½ inch ply topped by 1 ½ inch blueboard and 2x red cedar framing and a final layer of 1/4 inch ply. Cabin walls are similarly insulated, but with an inner face of 1/8 inch mahogany ply (in place of the 1/4 inch ply).

The decks are sheathed with Dynel (acrylic) fabric set in epoxy. The hull is painted with latex primer and topcoat (we would have like to resin coat, but ran out of weather).

Outside windows are 1/4 in Makrolon (scratch- and UV-resistant polycarbonate) bedded with BigStretch (latexy stuff) and fastened with stainless steel screws with finish washers. Windows are doubled, inside, by 1/4 or 1/8 in acrylic.

We generally fastened with bronze ring-shank nails, and used a medley of glues: 3M5200 for all exterior hull joins, combining with SikaFlex to glue copper to ply. NOTE: the SikaFlex failed drastically once we got her in the water! We had to screw the copper to the hull after launching to secure the sheathing.

Weldwood Plastic Resin for flat lumber glueing, Henry Cove Cement (experimental... mixed results) for the foam, System Three epoxy for sheathing, fillets (thickened with white, bleached flour) and general pucky Special thanks to Gorilla Glue (liquid polyurethane), which continued to function into 20°F weather, and was used whenever we needed a quick glue job.

As a retrospective note, we should have glued all the blue board with epoxy, despite the cost. The time savings (of using a single glue) and end-result (we had a little separation with the cove cement) would take the sting off the price tag.

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How long did it take you?

Four and a half months (15th August to 30th December, 2008) start to launch, with no interior or rig. Two of us worked full time. I’m hoping that we’ll be finished and sailing in the next five months, working at a much more sedate pace, and with considerably less infrastructure.

It was supposed to have been a two to three month project, excluding planning and shopping. Circumstances included these, and we were cursed with material issues (non-standard plywood, poor lumber and irregular copper plate) and the coldest, wettest summer and autumn on record (which includes a lot of cold, wet years!). This slows glue and made me slow and stupid. My guess is that, otherwise, we would have gotten much farther on our original schedule. There were no surprises in the construction.

How much did it cost?

Roughly $10K (Sitka, AK dollars... things generally cost 10 to 25% more, here, or to get them here) in materials and space rental ($1200 for rent, $500 for tent materials). About half of that went to the copper, bronze and aluminum, which we appear to have purchased near peak price (copper plate was $5.35 / lb). We probably have $500 to go in sailcloth and miscellaneous expenses.

Why sheath a boat in copper?

Elemental copper is non-toxic [possible factoid alert] (as opposed to cuprous oxide, which is toxic). I've read that it generates an electrical field, or ‘taste’, which discourages growth (fact: growth is discouraged). We've had to lightly scrub a thin, slimy growth from LUNA’s sides two or three times a year. Rumor has it that a night in fresh water kills the slime, which washes off next time underway. Hasn’t worked for us (Southeast Alaska has a lot of freshwater on the sea surface after frequent, heavy rains—could be that growth is adapted for reduced salinity?).

The main advantage, to our mind, is mechanical protection when dried out between tides. Copper plate is wonderfully abrasion resistant. Backed by plywood, thin plate resists deformation. Secondarily, as toxin based paints must now be scraped and renewed in containment facilities (expensive haul-outs), the copper pays for itself in a few years.

We covered the chines, where the plate edges meet, with 1/4 in bronze angle, screwed and glued. This should protect them from rocks when settling down on rocky ground in windy conditions (boats sweep laterally at anchor... the chine will come up hard against anything standing even a bit proud, just before settling or floating free).

Other hats include ballast, lightning dispersion plates, skim ice protection, inflation hedge, cool factor.

What was your intended purpose with this design?

We wanted to live-aboard the smallest sailboat with ample space and capacity for ourselves, gear, possessions and a year’s supply of staples. Small is easy to handle, maintain and berth. In emergencies (beached, say), small is easier to move by mechanical means.

We wanted to test a larger TriloBoat hull under sail. While sailing barges and scows once carried a majority of the words freight, much of their handling lore has vanished. We don't expect these to be stellar sailers, but I predict that they'll be enjoyable and reasonably able. Slacktide will give us some first-hand experience.

Sailing without an engine is very important to us. Conditions can pipe up abruptly in Southeast Alaska, and with little to no warning. Our run-from-weather technique is to run down-wind until a promonotory is reached, duck into the lee behind it, and beat back up to shelter. Thus, the minimum requirement for Slacktide is that she be able to beat, deep-reefed, in the moderate chop of semi-sheltered water in up to 45kts of wind. Slow to weather is OK, but has to be reliable. (The backup plan, seldom used, is to drive her up the first reasonable beach and ride the high-water mark up with the tide.)

Downwind, we expect sleigh rides.

Most of the time we’re poking along in nil to moderate winds, and hanging out in shallow bights and deltas. The large windows let us drink in the beauty around us from within the cozy cabin.

Another goal is to be able to ‘unfold’ various scenarios from the boat’s stores; ways, workshed, smoker and canning, laundry. This should allow us to stay remote from towns as much as we wish.

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How is Slacktide laid out?

At the very ends are two large, self-bailing anchor wells. Forward will be a pair of struts with rollers for a brace of ‘self-launching’ 25lb Manson Anchors, with two, smaller inline anchors on stand-by. Aft are two mid-size anchors for a total of six. We’ve standardized our gear and connections for more flexibility, and hope we won’t regret having dropped two anchors from LUNA’s repertoire. We’re hoping to make a mount for a Simpson Lowboy Capstan Winch that can be moved fore and aft as required.

Forward and aft of the cabin are two large holds, each with watertight bulkheads. These will hold deep-storage and second-tier supplies (to replenish, say, small galley containers). They also contain the gear for different project configurations.

The idea for SLACKTIDE was to containerize almost all her contents. Each hold takes a row of five, 18 gallon containers topped by a second row of 14 gallon containers against the inboard bulkheads, leaving about half its volume for dry-bags and the like. When cleaning in the wilds, we can divide-and-conquer (we hope), cleaning area by area, contents of which are contained, controlled and protected from the elements by their water-resistant storage.

Containerization is a response to LUNA’s more traditional locker system. These worked great until cleaning time, when their otherwise loose contents needed to be evacuated, usually without reliable temporary shelter. Temporary containers were required, usually boxes (only available in town), and makeshift shelter (tarps) improvised. Any serious down-turn of weather would abort the whole effort. The result was that we ended up chasing dirt (and eventually mildew) from locker to locker... never completing the bow to stern sweep that should be done each year, while sucking up weeks of the best cruising weather.

The fully insulated cabin is built around the ‘flexi-space’ concept (I believe the term was coined by J.Wharram, but was well known to most everyone before the advent of stone floors). The open, 10' x 6'8" platform area (directly on the inner face of the hull) has a 2' strip, aft at the companionway, for boot and wet-gear removal. The fwd 8' will have an inch of close-cell foam with carpet over. A double van-(sleeping)bag with mattress will roll up into a long cushion for daytime lounging. We can sleep three longships or five (if we're crazy enough) thwartships, before spilling onto the decks. Starboard is a small table surface which stows flat against the hull when not in use. Most of the time, we foresee sitting, kneeling or lounging directly on the carpet, but also have a pair of foldable chairs for western-style seating.

Forward is a 2' deep ‘strip-galley’, with a counter-top at 16", hanging and shelf storage along the walls and bulkhead. To port will be a large drawer with a ‘bread-board’ lid... when drawn out, it will provide extra counter-space while the bread-board gives access to its contents without having to clear it. A shallow drawer for flatware, a medium one for miscellany, and a small woodbox complete the under-counter storage.

One amenity that we’re foregoing is a sink. Dishes will be done, standing in the companionway, sheltered by the scuttle overhang (and possibly a buggy style extension). This system worked well on ZOON, and discouraged the stockpiling of dishes in the sink. We have a whale-gusher pump which’ll provide salt-water to the back deck for utility, and a large, dedicated coffee pot for heating wash water. Port and starboard of the galley (forward of the windows) are small, gasketed, opening ports for ventilation.

The starboard bay of the galley will have a small woodstove. We hope to build a small, airtight firebox with a relatively large cook-surface and a kindling sized rocket stove ( integral to the box. This should let us produce an efficient hot spot for warm-weather cooking, efficient long-term heating in the airtight portion or any combination between. In addition, we want a charcoal-burning Lenihan heater for heating without cooking.

Aft, and extending under the aft deck is a 2'x3'x6'8" alcove housing a chest-of-drawers. Each of us will have three drawers, outboard, with the middle being communal. All drawers will have lids, which make them weather resistant and function as seats or tables. The lower drawers will hold heavier items (books, tools, batteries, etc) and double as seats for inside steering. The mid-drawer will triple as a step up to the companionway. Above that is a bin to absorb footware, and a shallow navigation drawer under the center deck.

You may have noticed a certain lack of privacy. We need to be pretty comfortable with the folks we invite aboard for long, and visa versa. This will be a bit more acute, even, than on LUNA, which didn’t have large windows overlooking the foredeck. A daily ‘constitutional’ can usually be coordinated with a trip ashore, and the rest is a piddly affair. We plan a curtain to slide around the scuttle cut-out, which will afford, at least, some visual privacy, and help keep rain out off the central carpet on wild days, running.

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How are the decks laid out?

The fore deck has its two hatches proud of deck level, accessing anchor well and hold.

The cabin deck has a small galley hatch forward and the scuttle, aft, with drop-boards. We’d like a solar panel or two running down the middle. Large, outboard footrails (shaped like handrails), along with jacklines help keep us onboard.

The aftdeck’s hatches are set flush, to minimize toe stubs and provide a more comfortable outside sleeping platform. A thwartship bench is fixed dead aft, and it, with a movable one matched to it, can be used for seating or workbenches (the movable one also can be used as a rather short fenderboard). Two fat, cylindrical fenders stow under the bench, and can be used as low, soft seating.

How are you going to rig her?

Slacktide will be a junk ketch, with mainmast stepped in an aluminum tabernacle at the forward cabin bulkhead, and the mizzen at the aft cabin bulkhead in a wooden tabernacle.

Sails will be identical with the following exception: the main (foreward sail) will have one extra panel, and be spread by three pairs of battens, its sheet led aft. The mizzen (after sail) will have five battens, and its sheet led forward along the lowermost (boom), then down and aft. Both will be handled forward of the person at the helm.

We'll put both of the junk (lug) sails to port, this time. This puts maximum efficiency on the starboard tack.

This time, we’re going to try a fabric called Top Notch, which is made for sail covers (not normally used as sailcloth—rumor has it that Tom Colvin has been using it or similar materials for his junk rigs). It’s polyester with a UV-resistant, acrylic coating, and claims to have the stability and chafe resistance of the former and the longevity of the latter. We never cover our sails at anchor (most of the year), as, without a motor, they need to stand ready for immediate use in (very rare) emergencies. We hope the UV-resistence will extend their lifespan considerably.

We’re using off-centerboards, again, but ‘bearing plate’ style, this time. This means the pivot is in the middle of a bearing plate which fetches up against the hull chine on the lee side and the cabin overhang on the windward side (leeboards can only be used on the lee side, and must be overhauled every tack).

The pivot will travel with a ‘car’ along aluminum, C-section girders mounted just under the windows. Top pivoting boards, while much simpler, block the side windows, when stowed - something must be done! We’re hoping that the extra cost and effort will pay for itself with the added benefit that we can radically adjust Slacktide’s Center of Lateral Resistance (CLR). This is especially important as the windows push the boards and therefore the CLR rather far forward (there is no foresail to do the same for the sails' Center of Effort (CE)). Also, when running in gusty, gale-force wind, a brief pickup in wind speed can overpower the rudder, rounding us up. Hauling one or both boards aft will help us track down wind, reducing round-ups.

Meanwhile, the girders overlap the cockpits and provide boarding steps. Their transverse stiffness, along with the 2x4 framing which backs them interior to the composite wall, will help support the cabin walls (which have no interior furnishings to support them).

The rudder will be outboard and kick-up, but (hopefully) an improved design over those I've seen and used. Its rudderpost will angle aft (rather than vertical or forward), improving the balance (area forward of the rudder’s turning axis) for easier steering. It will be rather large, to help counterbalance the area of the boards (when in forward positions). Its forward curve will come almost to its trailing edge, eliminating the flat section along the bottom of Luna’s rudder (if one forgets to raise a flat-bottomed rudder and the boat settles down with the tide, it may not roll forward, but rather take on a whopping chunk of the boat’s weight). Lastly, the radius from the pivot to the tip of the ‘hook’ at the forward, upper point of the rudder will be a few inches less than the height of the pivot plus the draft. Thus, when set horizontal in shallow water, the hook (now pointing down) has less draft than the hull and won’t drag bottom.

How about auxiliary power?

We’ll still have a yuloh (Chinese sculling oar) for quick grab and short hops. On Luna, we could go all day at a knot and a half, with 15 minute (or so) sprints to a smoking two knots. Over long hauls (windless days with a schedule to meet), though, it's hard on the elbow joints.

A twenty foot pole scoots us along shallows (what fun!). More importantly, one of us sits with it, forward, and forces the tack in tight situations where an edge or the bottom can be reached (and, I mean, really... when else is it ever 'tight'?).

We also have a Seacycle Pedal Unit, which is like an outboard motor, but with bicycle type pedals at the top. This is a nice looking unit that develops quite a bit of push (no numbers, yet). We’ll mount the unit from the aft deck and straddle the boomkin (with maybe a banana seat?) to sit and pedal. With luck, we’ll get three or more knots at moderate rpms. Three knots, if we get it, exceeds most open-water currents (constricted passes, no), and will take us to an anchorage in a reasonable amount of time, most places.

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What special gear will you be carrying?

The special gear is mostly for moving the boat in dire straits.

A screw jack (hydraulics are easier to use, but prone to failure in salty, sandy environments).

A Maasdam Rope Puller (like a come-along, but for rope, using a clutch which allows ‘endless’ line—fits our anchorlines).

A chain hoist for short, heavy duty pull.

If we can stand the weight, a cable clutch puller and cable. These things, sometimes called ‘elephant ears’ are heavy duty pullers with a long reach. ‘Bout a hundred pounds of ironmongery, though.

What elements are untried, and why are you trying them?

The large, open interior of the cabin has more unsupported space than I've encountered. I call this type of bottom a 'trampoline' structure; like a trampoline, deflection of the surface (wave pressure or drying out on a lump or rock, say) pulls all along the perimeter of the unsupported space (along the chines and main bulkheads, in this case). The inherent strength of the bottom plays a role, as well (being flat, though, it's not nearly as strong as a convexly curved- or V-bottom of the same thickness). I estimate (note that I am neither a naval engineer nor an architect) that the edge structures are sufficiently strong to accept the stresses reaching them.

I'm trying this because the open interior doesn't allow structural furniture, and, as displacement is limited, I'd like to avoide the extra materials weight for a raised sole (with stiffening framing below). A non-liveaboard (unburdened by the 'unbearable lightness of being') might well consider the raised sole/stiffener approach. (NOTE: the bottom feels plenty stiff afloat—we have yet to let her go dry).

The moveable bearing-plate off-centerboards have a number of details which may do better on paper than reality, including the engineering of the car, or travelling block (carrying the pin fore and aft along the girders) and moveable leads for the board-hauling line.

A particular problem arises dropping or raising the windward board. It's upper end is forced inboard, toward the delicate windows and under the eaves. A strut from girder to the upper bearing strip along the eaves guides it and protects the windows. Being movable, however, I'm considering up to four struts, at various common positions, in order to cover accidental kick-ups (i.e., when encountering unexpected bottom).

The boards are moveable for reasons explained above (clearing the windows and CLR adjustment).

Sailing this type of barge hull has been done, but the techniques and body of knowledge has become diffused (at least I've had a hard time tracking it down). TriloBoats appear closest to the pontoon-barge-to-yacht conversions, which were both somewhat common and reportedly beloved. Within appropriate expectations, I expect them to be fun and able, making up for a lack of dazzle in bang-for-the-buck and creature comfort in harbor. To get the best out of her, I expect a learning curve with a relatively gentle slope.

So you've launched her—what are your initial impressions?

She's sitting above her target DWL (8 1/2" now, 10" target with about 650 lbs per inch of immersion... about 1000 lbs to go) so will be able support the rig and various interior components (most of everything is already aboard).

She's very stable for her size, depressing about an inch when I step aboard, then recovering with no further roll. I can set her rocking, if I work at it, but can only go so far (no apparent 'death roll' dynamic).

The view is most excellent (we have Mt. Edgecumbe—a dormant volcano—to starboard and the forested slopes and snowy peaks of Gavan, Arrowhead and the Sisters to starboard).

No big chop, yet, but a four inch ripple makes a pleasant chuckling sound similar to Andy Stoner's T32x12. He reports zero pounding at anchor. My theory is that the "pound" is like hands clapping and occurs when wave pitch matches that of the salient bottom at the bow. The steeper angle of the barge in comparison to an Advanced Sharpie means that wave pitch would have to be much higher before pounding occurs... a pitch unlikely to be found in a sheltered anchorage.

Towing her to the harbor, she slipped along well, though there is an odd curl port and starboard where the wake along the chines collapses inboard. We'll see if this creates significant drag when running upright. The wake appears nice and flat, otherwise. I'll be watching closer when the next barge comes to town.

All in all? First impressions are favorable.

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