Rouleur’s canting dagger boards: balancing lift & drag in small R2AK boats

An interesting aspect of helping Matt build his Race to Alaska boat is learning from him, the boat designer Rick Willoughby, and other contributors how important aero- and hydrodynamics are to creating an efficient boat.  When you can only provide ~250 watts of propulsion power (or 500 in Matt’s case), rather than the normal 3600 watts you get from a 5 hp outboard, you need to minimize drag in order to attain admirable boat speeds.

Matt’s boat is version 16 of a pedal boat designed by Rick.  This V16 R2AK is modified for the Race to Alaska in many ways, but one key one is the canting daggerboards.  These foils are designed to be elevated above the waterline so that Matt can pedal without any water drag from them, and then  lowered during sailing to to provide lateral resistance and lift that helps keep the boat from heeling.

When lowered to the maximum angle of about 55 degrees below horizontal, the leeward daggerboard will help with upwind performance.   On a reach it could be raised to provide more lift, while on a run it can again be pulled up clear of the water.

Here are some photos of the dagger boards — both during construction and initial sea trials.

We ended up deciding to shorten the struts from about 63 cm to 58.5 cm LOA.  This allows the struts to come up above the water line (and hopefully many of the smaller waves) and be lowered down to near 55 degrees below horizontal.

Here are the struts after being shortened experimentally to about 60 and 58.3 cm LOA…



It was clear during testing in the lake that the bare aluminum struts were creating a LOT of drag.  Rick explained that fairing them (with a symmetrical foil shape) would reduce the drag by about a factor of 20.  Sailing with them immersed was equivalent to pulling a second Rouleur hull behind us!

Here are a few more photos of the fairing of a second set of struts (made with slightly thicker walled aluminum tubing, too, I think).  This set was faired with cedar, though we may fair the original tube with foam insulation to have a backup (lighter duty) second pair.

The astute reader will notice that I drilled the holes 90 degrees off in the ends of the struts!  This was remedied by re-squeezing the ends (I did this in the vice already without cracking any epoxy, thankfully) and re-drilling (much easier to line up the holes when you’ve got the faired foil shape behind the bit in the drill press!).  Any strength lost from the initial errant holes I hope to regain by injecting silica-epoxy plugs 2-3 cm into the tube ends.

I’m excited to see what these faired struts do for Rouleur’s speed.  So far she’s not quite attained the sailing speeds that Rick expects from his modeling…

Human-powered boat speeds at the start of the 2015 Race to Alaska

While most of the 2015 Race to Alaska (R2AK) was rather breezy, the very beginning of stage 2 (from Victoria to Ketchikan) offers an opportunity to compare the speeds of the diverse boat types in the fleet.  Not only is sailing not allowed in the inner harbor of Victoria, but there was virtually no wind during the first couple hours of the Race.  As the ebb tide weakened and the bulk of the fleet made the big left turn from the Strait of Juan de Fuca into Haro Strait, a light southerly filled in and the sailboat race began (see plot of wind speed at Kelp Reefs below).


Not until 2 p.m., a couple hours into the 2015 R2AK, did the southerly begin to flow up Haro Strait.

This near-calm period affords an opportunity to compare the speeds of the many different types of human-powered propulsion that were utilized by the 2015 fleet.  Boats with a wide range of designs and displacements used oars while others tried 1- or 2-bladed paddles.  A hand full of technological innovators used pedal-powered propellers or adaptations of the Hobie Mirage drive.

The fleet under human power along the shoreline south of Victoria.

The fleet under human power along the shoreline south of Victoria.  (Photo from

While a more quantitative assessment is warranted (maybe with GPS Action Replay?), with the excitement of the 2016 upon us, I tried a simpler approach.  Assume that everyone started at about the same time (high noon on Sunday June 7, 2015), that the whole fleet cleared Point Gonzales before any meaningful amount of wind set in, and that everyone experienced about the same set from the ebb. Here’s the current situation at Race Rocks for that day:

2015-06-07 Sun  5:14 AM PDT   Sunrise
2015-06-07 Sun  5:38 AM PDT    0.6 knots  Max Flood
2015-06-07 Sun  6:47 AM PDT   -0.0 knots  Slack, Ebb Begins
2015-06-07 Sun 11:12 AM PDT   -5.3 knots  Max Ebb
2015-06-07 Sun  3:05 PM PDT    0.0 knots  Slack, Flood Begins
2015-06-07 Sun  6:09 PM PDT    5.3 knots  Max Flood
2015-06-07 Sun  9:11 PM PDT   Sunset

With those assumptions in place (and with the caveat that any ebb current would reduce the apparent speed of the R2AK boats as measured by their SPOT transceivers), I next measured the point-to-point distance from the Empress marina in the Inner Harbor of Victoria to Point Gonzales (just NE of Trial Islands).  It’s ~10.5 km.  I then used the R2AK tracker re-play function to estimate the time that each boat passed Point Gonzales.  (This is a little tricky due to the 15 minute location interval, but if we assume constant speed during those 15 minutes we can approximate the time at which a boat passed the Point to within a minute or two.)

Here are the results (also available within this Google spreadsheet of Inter-annual R2AK Statistics) —

Team Human power (primary) Victoria – Gonzales Pt. (10.5 km) speed (kts) Victoria – Gonzales Pt. (10.5 km) speed (kph)
Broderna oars n/a  n/a
Barefoot Wooden Boats oars n/a  n/a
Soggy Beavers paddle 5.00 9.26
Hexagram 59 pedal 4.00 7.41
Sea Runners pedal 3.70 6.85
Turn Point Design pedal 3.66 6.77
Discovery mirage 3.58 6.63
Mike’s Kayak paddle (2 blade) 3.40 6.30
Pure & Wild pedal 3.27 6.06
Boatyard Boys oars 3.15 5.83
Mau pedal 3.09 5.73
John paddle (1 blade) 3.04 5.63
Elsie Piddock oars 2.93 5.43
Puffin pedal 2.91 5.38
MOB Mentality oars 2.88 5.34
Kohara pedal 2.86 5.29
Un-cruise mirage 2.79 5.16
Blackfish oars 2.77 5.12
Grin oars 2.77 5.12
Por Favor oars 2.77 5.12
Golden Oldies oars 2.68 4.96
Coastal Express oars 2.52 4.67
Excellent Adventure oars 2.50 4.63
Real Thing pedal 2.38 4.41
Free Burd oars 2.36 4.38
Y Triamoto oars 2.36 4.38
Super Friends oars 2.36 4.38
Seawolf pedal 2.00 3.71

The range of speeds (5.0-2.0 knots, or 9.3-3.7 kph) is not that big — though it feels substantial when you’re getting passed by someone on the course, or trying to catch up to a boat that’s “just ahead!”  I certainly recall being appalled at how fast the Soggy Beavers (44′ OC-6, mean speed 5.0 knots) overtook our 17′ catamaran (pedal+paddle power, mean speed 3.7 knots) in the first few minutes of the race (see below)!  [There’s no data for 2 boats that had SPOT trackers that weren’t working during the start.]

Six-minutes after the bell, the Soggy Beavers pass Team Sea Runners on route to set the Point Gonzales speed record:

Six-minutes after the bell, the Soggy Beavers pass Team Sea Runners on route to set the Point Gonzales speed record: 9.26 kph.  They passed Point Gonzales just one hour and 8 minutes into the 2015 Race to Alaska.

The fastest boat (Team Soggy Beavers) was a long, narrow, lightly-loaded hull propelled by Canadians using the most tried-and-true technology on the Pacific Northwest coast: the canoe paddle.  The next three fastest boats used pedal drives, assisted in some cases by a paddle: Hexagram 59 was relentless in their use of a supplementary SUP paddle (always on the port side!); Sea Runners occasionally took vigorous strokes with a canoe paddle.  Turn Point Design had a carbon fiber cat driven by the largest prop among the pedal-powered boats.

One interesting pattern is that the next 7 top speeds were obtained with less traditional methods (not rowing).  After them, came the three fastest boats that were rowed: the Boatyard Boys (small boat, strong rowers; coincidentally almost matched by Team Mau with an athwartship pedal system), Elsie Piddock (the winners of the windy 2015 R2AK), and MOB Mentality.  This pattern hints that there are still speed gains to be made by both rowers and technological innovators.  This year Colin Angus and Mathieu Bonnier will bring a LOT of rowing experience to the race.

And Matt Johnson will bring some serious pedal power.  His interest in pedal-powered boats is partly fueled by an interest in breaking the World record for 24-hour distance in a human powered boat.  This Google spreadsheet of human-powered boat speed records and measurements shows how high the bar has been set over the years — primarily by pedal boats and kayakers.    The speeds maintained over 24-hours have been creeping up over the decades.  Kayaks have gone from 8.04 kph in 1988 to 10.15 kph in 2013, while pedal-powered boats have increased dramatically from 3.76 kph in 2000 to 10.22 in 2008.

Overall the 2015 R2AK boat speeds over those first 10.5 km bracket the speeds maintained over long distances by rowers and kayakers (3-5 kph; e.g. Colin and Julie rowing across the Atlantic averaged 3.9 kph).  But the upper R2AK speeds aren’t far from the World record paces of pedal-boater Greg Kolodziejzyk (10.5 kph) or Bellingham-based kayaker Brandon Nelson (10.22 kph).  The top sprinting speeds achieved historically indicate an upper edge of what current technology may soon deliver over a long course like the R2AK (ignoring factors that limit human endurance): 17.6 kph for Gordie Nash in a pedal boat; 20.55 kph (11 knots!) for Olympic kayak men’s K4 sprint.

Who do you think will beat the “Point Gonzales record” (of 5 knots) this year?

For the competition to be “fair” from year to year, the current situation should be about the same.  It looks like Jake did a good job of leveling the playing field:

2016-06-26 Sun  5:14 AM PDT   Sunrise
2016-06-26 Sun  5:26 AM PDT    0.0 knots  Slack, Flood Begins
2016-06-26 Sun  6:47 AM PDT    0.9 knots  Max Flood
2016-06-26 Sun  8:24 AM PDT   -0.0 knots  Slack, Ebb Begins
2016-06-26 Sun 12:18 PM PDT   -4.2 knots  Max Ebb
2016-06-26 Sun  3:57 PM PDT    0.0 knots  Slack, Flood Begins
2016-06-26 Sun  6:55 PM PDT    4.5 knots  Max Flood
2016-06-26 Sun  9:19 PM PDT   Sunset

The slack will come about an hour later this year, but the max ebb is about a knot less than last year.  May the best technology and most powerful racer win!


Solar electric systems for small boats in the R2AK

The Race to Alaska (R2AK) is an un-supported challenge in which reliable communication and navigation is important, but energy supplies are often limited.  Many of the smaller boats want to be light to make sailing or human propulsion faster, so taking tons of batteries isn’t an option.  Solar charging systems can be limited by inclement weather.  And getting wet is pretty much guaranteed on a small (<20′) boat.

Electrical system for cruising 21′ cat and Team Puffin (R2AK 2015, ~9.0 kg):

Here’s the system that Team Puffin used in the 2015 R2AK.  This set-up was derived from systems that were used aboard the same Wharram Tiki 21 sailboat (“Milagra”) during summertime cruises over the last 5 years.

Here’s some pictures of it in action during the cruising era:

Typical cruising loads as well as the loads required by Team Puffin were served through USB chargers that fit the cigarette lighter jacks.  The main power demands were for:

  • iPhones (with Navionics, MarineTraffic, and other apps)
  • VHF radio (plus a back-up)
  • iPad (only aboard with Team Puffin, and not used much as iPhones sufficed)

Electrical system for Team Take Me to the Volcano (R2AK 2016; ~7.8 kg)

The Tiki 21’s electrical box is being modified for use by Team Take Me to the Volcano in this year’s (2016) Race.  Matt’s main charging needs are:

  • VHF (plus a back-up)
  • Phone
  • Lithium-ion battery pack (a 20,000 mAH one costs ~25$ now! that’s 20 AH, so seems cost effective compared to larger motorcycle-sized lithiums…)


Most other items will be powered by disposable (mostly lithium AA) batteries:

  • GPS
  • Flash light / anchor light
  • Head lamp
  • Running lights
  • R2AK SPOT (lithium only)

Here’s a spreadsheet that compares the mass, cost, and other factors for the Tiki 21 system and the modified system for the V16 R2AK.

Based on these comparisons, here are the main modifications and improvements we are making:

  1. Lighten up the whole system by switching from lead-acid to a lithium battery, and possibly by using a less rugged waterproof case (new Pelican Air 1485 of sufficient outer dimensions is 2.1 kg, saving about 800 grams over current case)
  2. Add energy storage by using “bricks” now mass produced for recharging phones/etc that are charged via the USB ports
  3. Solder, stabilize, and marine-ize all wiring, terminals, and components

How will you power your R2AK? Here’s the system undergoing transformation from Team Puffin (2015) to Team Take Me to the Volcano (2016).

Here’s the final result.  This may still be too heavy for Matt to use in the R2AK, but it is an incremental improvement in the cruising system I’ll use aboard the Hitia 17 or Tiki 21.


The new and improved electronics box.

The main changes were:

  1. Lowered total mass by about 2.0 kg overall.
    1. The big savings of 2.1 kg was from switching from Pb-acid to lithium iron phosphate battery.  We take a little hit in capacity (going down from 12 to 9 Ahr), but presumably that can be supplemented by adding a USB lithium battery brick.
    2. Considered a Pelican Air, but the mass savings for the smallest that would fit the 10W panel was only 500 g.
    3. The Bioenno charge controller added ~110 grams over the BatteryTender one (but I hope it handles load vs battery maintenance more intelligently…
    4. I re-sealed the holes in the case with Tap Plastic’s recommended 2-part glue for polyethene (adding some glue mass, but simplifying the seal of a big historic hole in a way that reduced mass a bit).
  2. Testing extra capacity with Matt’s Aukey 20 Ahr brick, but may end up using a smaller one that I own…
  3. All wires are now terminated, soldered, and heat shrink tubed.  Battery, controller, etc are also much more secure — either lashed, screwed, or velcro-ed down.  I was surprised to see how much electronic complexity is inside the charging base for the VHF.  In a feeble effort to protect it, I added some shoe-goo to the perimeter of the base cover which is otherwise just held on by a single central (tiny) screw.  An added benefit of glue-screwing the base to the wooden board (which I moved and glued to the handle/edge) is that now the VHF can be used (for listening to weather, or even transmitting while plugged into the charger…

It’s not a simple connection of the 12V wires to the radio!

LiFePO4 battery details

I ran into two tricky bits in implementing the lithium battery upgrade.

First, not all lithium iron phosphate batteries are the same.  Some are aimed at maximizing lithium cranking amps (LCA) while others can tolerate deep cycling.  While offered an attractive lithium option (12V, 120 LCA, 0.5 kg, $100), they emailed to say that it really wasn’t appropriate for deep cycle use in a marine setting.  After searching around (and finding this very interesting Canadian electrical engineer who is making a solar charge controller for lithium PO4 battery banks), I ended up at BioEnno Power looking at their 12V series of LiFePO4 batteries about which they say:

These are Deep-Cycle Batteries for extended continuous use, not to be confused with High-Rate Batteries which are for starter applications only and not for extended continuous use.

I ended up choosing the BioEnno Power 12V, 9Ah Pb-acid equivalent LiFePO4 deep cycle battery.

Though it is only ~1/2 the mass of the current Pb-acid battery in our system and still costs ~4x as much, I’m excited for the weight savings and to try this new technology.  I was also motivated to go with them since they sell an AC charger ($22) and a 12V/10A solar controller ($40) that specify having a charging algorithm that is appropriate for LiFeSO4 batteries, though it’s not clear to me whether or not they use a 5-stage LiFePO4 charging algorithm that Battery Tender recommends.

Second, the weight savings seemed to vary a lot depending on the LiFePO4 battery manufacturer, or possibly the intended application: deep cycling vs high-rate.  For example the Battery Tender 12V/120LCA battery (which they bill as equivalent to a 7-9Ah Pb-acid battery) weighs 0.5 kg which is is ~1/7 the mass of the current Pb-acid battery’s 3.3 kg.  In contrast, the BioEnno 12V/9Ah battery has a mass of 1.18 kg — about 1/3 of the Pb-acid mass.  Even the 240LCA () Battery Tender option weighs only 0.8 kg (1/6th Pb-acid mass).  What could account for this factor of ~2 difference in LiFePO4 battery mass?  (Bolted vs welded connections between cells?)



First salt water launch and initial speed data

IMG_0325On Sunday (5/22/2016), Team Take Me to the Volcano launched the “V16 R2AK” at the Secret Beach in Ballard, Seattle.  Around 6pm Matt, Mark Dix (Team The Windsurfer, Stage 1 R2AK, 2015), and Scott finished bolting iakos to amas, having leveled the main hull and amas before drilling the final bolt holes in the inboard end of the iakos.  We loaded up the main hull on Mark’s car and the amas on Scott’s and headed (carefully, remembering Colin’s tragedy) down the curvy road to Puget Sound.

At the beach Chris and Mik met us and helped unload onto the sandy beach.  High tide was approaching, so once we re-connected the amas and main hull with some help from Sam (of Team Puffin, R2AK 2015), set up the seat and other gear, it was easy for Matt to pull the boat into the sea.

With Matt aboard and a fair amount of gear, the step out from the lower to upper hull was 95-105 cm above sea level.  We tried loading 50 pounds of weight behind the seat, but thought that pushed the rudder assembly a little too deep.  When Matt was pushing hard the steering arms on the rudder were mostly submerged.  With the 50 pounds removed, the rudder arms were clear of the water (except when waves passed over it).  Overall, it looks like it will be helpful to get some more weight up forward — which of course will happen when the sailing rig gets stepped (just forward of the forward beam).

With the initial trim set and some confidence that it wasn’t leaking, Matt brought the boat back to shore for a proper Christening.  Lisa and Ciana had arrived with champagne and proceeded to help Matt name the boat “Rouleur.”  The beautiful Douglas fir bows were glowing in the setting sunlight, glistening with the recent heavy rains, and foaming with celebratory champagne as we all hailed the arrival of another fine boat on our ocean planet!

Matt then took Rouleur out for another longer spin.  A few minutes after he had disappeared “upstream” toward the Ballard locks, it was an awesome sight to see him blaze bast a couple cruising kayaks.  It seemed he was suddenly off towards Ketchikan at high speed!  But he eased off on the power at the last-minute and circled back to us.  Near the beach a set-screw gave in to the tremendous torques Matt was pushing through the right angle drive, so our sea trials of the pedal propulsion system had to cease.  It was easy to return to the beach with gentle pedaling, and earlier it was clear that the back-up human power method of a SUP paddle was also effective.


Matt takes a seat he’ll sit in a LOT.


The view seaward from the hot seat.



Map of the 2nd test run (w/50 pound weights).


Speed vs distance plot for 2nd circuit.  Cruising speed was 8-10 kph.

The initial speed data suggest that in flat water and no wind, Matt should be able to keep this boat in the 5-10 kph range pretty easily.  Remember for the ~1200 km Race to Alaska, 10 kph mean VMG will get you to Ketchikan in about 5 days; 5 kph will get you there in 10!  Averaging 15 kph 24/7 will beat Elsie Piddock’s record handily; you’ll be there in 3.3 days!

For comparison, when Greg set the world record for distance in a human-powered boat over 24 hours, he averaged 10.22 kph.  Here’s a spreadsheet of long(-ish) distance speed means for human-powered boats.  While sprinting kayaks can hit 17-20 kph, a huge question in the 2016 R2AK — especially if there are extended windless periods — is whether Matt’s cycling prowess and the Rouleur’s pedal-propulsion system can sustain ~10 kph over significant stretches of the BC coast.


Longer 3rd run (50 pound weights removed).


Speed vs distance for 3rd, longer circuit. Top speed was about 13 kph, average about 10 kph!

My favorite part of the evening was seeing Rick Willoughby‘s design assembled and afloat.  The curved iakos seemed to connect in a near-circular arc.  Rouleur seemed perched on the water’s surface, wings outstretched — both embracing the sea and poised ready to streak across it.

IMG_0310 IMG_0318

Canting twin daggerboards

One of the unique features of my new Race to Alaska trimaran are the canting dagger boards. They were designed by Rick Willoughby. Not only will the boards provide lift, but they will help counteract the heeling forces from the sail.  I have very low volume stabilizer floats, so this lift will help keep me sailing level in a moderate breeze.

Canting daggerboards near front crossbeam

Canting daggerboards near front crossbeam


The daggerboards can cant from 60 degrees off horizontal to about 10 degrees,  where the tip of the board is clear of the water.  The adjustment is made by moving the inboard end of the brace up and down the guide rod. Originally this control was going to be with control lines, but now I believe I will reach forward and do it by hand. It pays to have long arms.
When sailing you lift the windward board and lower the leeward board each tack.  When reaching both boards could be lowered to provide lift. The boards will also have a friction release of the board on the hinge plate so it is not fatally damaged in a collision. While these foils are not designed to fly the main hull, in the right conditions there will be some lift, and increased speed.
Daggerboard control rods along the side of the hull

Daggerboard guide rods along the side of the hull

Daggerboard hinge plates

Daggerboard hinge plates


Cutting a big hole in my boat

Tonight I tackled the installation of the pedal mast and gearbox. Just another challenging job that I couldn’t afford to mess up. First I had to cut a big hole in the boat where the Mitrpak right angle gearbox will go. The shaft in the photo runs between a pillow block inside the pedal mast, and out to a coupling to the gearbox. The lower 14 tooth cog will attach to it.

Hole for mitrpak gearbox

Hole for mitrpak gearbox

Next I did my best to line everything up




The prop shaft will actually run along the side of the boat. The hole is cut in the cockpit sole which hangs over the main hull about the width of the gearbox.


Here everything is epoxied into place. The Pedal mast aluminum plates are bedded in epoxy, and sitting on a little square of fiberglass. Tomorrow I will fiberglass over the top of the attachment plates for the pedal mast.

The boat: V16 R2AK by Rick Willoughby

Below is a drawing of the latest design by Rick Willoughby. — a custom trimaran or stabilized monohull focused on enabling Matt Johnson to compete in the 2016 Race to Alaska (R2AK).  Rick is an Australian engineer who designed the V series of pedal boats, on of which was used to set a World Record for 24-hour distance attained in a human-powered boat.  Rick has pioneered the flex shaft propulsion system and dipping rudders, and in this R2AK-specific sailing design has also included a centerboard and canting foils.



Screen Shot 2016-03-02 at 1.25.31 PM

Building hulls through the winter

Over the winter of 2015-2016, I stopped by Matt’s house in Ballard a few times to help him build the hulls for his V16 R2AK.  It was a pleasure to work in his recently re-organized shop, in part because I always get good ideas about how to improve the work space in my garage and often get to try using nifty tools — some of which I’ve never seen before!

December 8, 2015

After checking out the table and chop saw work bench that Matt built, we epoxy coated some long lengths of door skin and then started laying out the bulkhead positions for the amas.  I love that Rick’s plans are all-metric!


We used hot glue to tack the foam bulkheads in place.  It seemed to work pretty well, though you had to work fast and together to insert the bulkheads before the glue cooled too much.


The amas have a nice knife-like profile.  Suddenly straight door skin panels start to look like they might move through the water pretty fast…

January 3, 2016

After the holidays we dry-fitted the base of the main hull.  It was tricky to get the longer door skin panels to hold a smooth curve, especially between the bulkheads and near the re-curved part of the bow.


After consulting with Rick, Matt decided to add a few stringers, so we worked together to rip them on his table saw.  I also did some sanding of some a previous epoxy coat that had beaded up in an interesting pattern of stippled patches.  It was nice to have the shop vac set up to filter out the dust.


February 11, 2016

Now the main hull is taking form enough that one can imagine pedaling and sailing within it!


We weighed it and Matt portage-posed with it before settling into the main job at hand: gluing decks on the amas.