It's All in the Legs
by Kellan Hatch

I have been haunting the internet for the past couple of years looking for the ideal way to add pedal propulsion to my sailing kayak/trimaran. I pop up on Yahoo groups from time to time and annoy people with the topic. I think a lot of people perceive pedal-powered boats as just plain wacky. Maybe they associate them with those plastic paddlewheel atrocities that you can rent at beach resorts. I don’t know, but I had my own reasons for taking pedal propulsion seriously.

My first goal was to avoid at all costs the tyranny of the internal combustion engine. A close second was to provide an alternative to paddling. You’re wondering what I’ve got against paddling. That’s the common solution for moving sailing canoes and kayaks around when the wind dies, right? Not for me. I have this… thing. I don’t even know what to call it but it’s a condition in my arms and shoulders that I’ve had since I was a kid, some sort of muscle/tendon weirdness that very efficiently converts repetitive circular motion into searing pain. Two hours of paddling equates to twenty hours of paddling regret.

Pedaling under full steam

I considered electric propulsion: unnecessary complexity and unwanted reliance on maintaining a battery charge. I’ve done a lot of rowing lately too. It’s not as painful as paddling but I really prefer to face forward whenever possible. Oars aren’t really an option for this boat anyway; there’s no room for them when the sailing outriggers are attached. I’m intrigued by yulohs and sculling too, but that’s still an arm thing and just isn’t very practical for a kayak hull.

So my checklist always brought me back to pedal power. And why not, they tell me that your legs have the strongest muscles in your body. Legs exist for the sole purpose of locomoting. Arms are meant for things like throwing rocks, rubbing sticks together and peeling bananas. I maintain that your arms were never meant for locomotion.

I’ve been scouring the internet for some time and I think I’ve seen every pedal operated gizmo out there. Many are massive, ungainly Rube Goldbergian contraptions with belts and pulleys, chains and gears, cranks and universal joints. They either use long drive shafts to get the power aft or they sling a pylon and propeller under the hull, consequently adding a couple of feet of draft to a boat that should only draw a couple of inches. Some are fairly impressive feats of engineering, but when it gets down to trying to buy one, most turn out to be yet-to-be-marketed prototypes or the fevered dreams of mad tinkerers, just over the horizon from being an actual product that you can buy and install in YOUR boat. And the ones that are on the market tend to be expensive, often more than double the price of the boat itself.

And then there’s the Hobie Mirage Drive. As close to proof of the existence of God as you’ll find. If you haven’t seen this thing, it’ll knock your socks off. Or at least it should. No propeller. It’s driven by two smallish fins -Hobie calls them sails- that sweep back and forth beneath the hull as you pedal. It adds a little more than a foot to the draft, but the sails fold neatly up against the hull for beaching. In fact, they end up horizontal at the end of every stroke so, get this, in extremely shallow water you can feather the sails close to your hull for partial thrust. And it’s compact; a single integrated unit that you can easily carry in one hand.

It’s so small you’d have no problem stowing it on board if you wanted to remove it while sailing.

Another great thing about pedal drive is that it frees your hands for things like steering, sailing and peeling bananas. Hobie provides an optional sail rig for their Mirage kayaks, so you can pedal, paddle or sail, or any combination of those – all three at once if you’re coordinated enough. I’m not.

I had the opportunity to test drive a Hobie Mirage kayak a few months ago and I knew that I had finally reached the Promised Land. I could easily maintain 3-1/2 to 4 knots for an indefinite period. And it was fun. And easy; virtually no technique to learn. The pedaling motion seemed very organic and natural. It was a comfortable motion. My hat’s way, way off for Greg Ketterman, Hobie designer and inventor of the Mirage Drive.

The obvious hurdle for retrofitting the Mirage drive onto another boat was that the drive was designed specifically to power a sit-on-top kayak. It just drops through a big, open, wet slot in the bottom of the boat. It appeared that, even if I could get my hands on a Mirage Drive, there would be no way of sealing it to keep the water outside my hull.

Then I realized that it’s essentially the same problem as putting a daggerboard in a trunk. I could mount the Mirage Drive in a well in the floor of my cockpit. I just had to make sure that it was deep enough to keep the water from flooding into the cockpit, plus a few inches of safety margin.

The trunk with drive in place

I went to the local Hobie dealer to see if he could order a Mirage Drive for me and he actually sold me one right off his stockroom shelf (a bit reluctantly – he’d have preferred to sell a boat to go along with it). I had already worked out the installation details on paper.

I think it was the same day I bought my drive that I found out that a member of the Yahoo Proa File group, Gary Lepak was also in the process of mounting a Mirage Drive in a small proa that he’s building. Ok, I have to make a bit of a guilty confession here. Gary lit the fire under me to get mine on the water first. A bit childish, I know, but thanks to Gary for the added inspiration.

Anyway, a few days later I had the thing installed and ready to test. Anyone who’s cut a hole in the bottom of their boat can attest to the degree of psych required to make the first cut. You stand there, tool in hand, feeling like you’re on the verge of committing to a DIY appendectomy or something. I built an eight-inch deep trunk around the hole. Said hole is actually a diamond-shaped slot that fits closely around the drive’s nether regions. My boat typically draws about 3 inches, but I made the trunk about as deep as I could without interfering with pedaling. That brought it almost up to the cockpit edge, which will certainly help if I find myself in need of bailing out. Anyway, by the next day the fillets had set up and I could see no reason not to try it out, so I loaded everything onto the roof rack and packed the family into the pickup for a drive up to the nearest reservoir.

The boat in question is a kit-built CLC Mill Creek 16.5 open cockpit kayak. I’ve rigged this boat to also be configured as a sailing trimaran (see my article: A Curious Boat for Questionable Adventures in the Duckworks archives) but it strips down to its basic paddling hull, leaving only a couple of bronze cleats to indicate that there’s anything more than meets the eye. I built a kick-up rudder that’s operated by means of a push-pull tiller.

Easily beached with drive installed

Once the boat was in the water I dropped the Mirage Drive into the well, flipped the latch bolts and I was ready to pedal.

Hobie claims that one man pedaling a Mirage Drive is equivalent to two men paddling. They even have a movie on their website of a one-on-two tug-of-war against two strong paddlers. I’ll have to take their word for it, but I can tell you that I was sure getting a lot of forward movement for the amount of energy I was putting into it. On my initial test I pedaled for about two hours, stopping only to pick up and drop off kids, without any appreciable fatigue. I clearly could have kept it up for hours. I’d say the effort needed to maintain around 3-4 knots (I haven’t bought the optional speed indicator yet, so I’m guessing based on how fast I was passing surface bubbles and floaters) is about the same as pedaling my mountain bike up a slight incline. As far as I could tell, my Mill Creek seemed to move about as well as the stock Hobie kayak. When I test drove the Hobie boat a few months back, speed indicator attached, I could easily stay in the 3 ½ to 4 knot range. I maxed out around 5 ½ , but it took extreme effort to keep up that kind of speed. 3 ½ knots will get me anywhere I need to go.

Skipper in front, engine in back

There’s no room in the trunk for the turnbuttons that Hobie uses to lock the Mirage Drive into their boats. The trunk is big enough as is, and that would add unwanted inches to its width, so I opted for a slide bolt arrangement. I was hoping to find something in stainless steel but ended up with a pair of brass cabinet latches.

I do have a few minor negatives to report:

First of all, there’s no reverse gear, so I use a paddle when I feel the urge to go backwards.

Also, the sails tend to whack against the flat bottom of the Mill Creek’s hull. No big deal, but kind of annoying. I quickly learned to moderate my stroke to eliminate the thumping. I’m not sure why, but this slightly reduced stroke also seems to be slightly more powerful. Probably something to do with reducing vortices between the sails and the hull or something.

Finally, the pedaling posture raises the boat’s center of gravity and reduces its stability. Fortunately, the Mill Creek has a very wide beam for a kayak, so stability isn’t nearly as much of an issue as it would be with a narrower hull. I may build a pair of small stabilizing outriggers like I’ve seen used on some prop-driven HP boats, just for some additional confidence on rough water and longer crossings. Of course, it’s a non-issue when I’m in trimaran configuration.

All in all, the trial run went as well as I could have hoped for. I was very, very pleased with the result – in fact, I can’t remember the last time I was this pleased with ANYTHING.

The following weekend I was on the water again, this time with the goal of getting good enough data to calculate my pedaling speed. I made a five-mile run, part of which provided very accurate time and point-to-point distance measurements. With the use of a topo map I was able to determine that the return leg of the trip averaged 4.4 MPH, which works out to just a little more than 3.8 Knots if we’re keeping it nautical. Not bad.

I’d like to cover a lot more distance on another excursion before the weather turns too cold. I’m hoping to make a round trip out and back to an island in the Great Salt Lake, about 15 miles of open water, if I can get way for a full day. I should probably build those stabilizers first.

I’ll let you know how it goes.

Follow-up

Approaching Fremont Island

My trip to Fremont Island in the Great Salt Lake went off without a hitch. It was a glassy-smooth day; the kind I've cursed a hundred times when I was trying to sail out there, but ideal for this pedal-only shakedown. The whole excursion took about five hours, including a stroll on the island before I headed back. The Mirage Drive performed very well in every respect. My average speed (although I don't have any kind of accurate measurement) was definitely less than on my initial tests. I'm not sure if this was simply because it was a longer trip and I was being careful to keep plenty of stamina in reserve, or if additional friction from the denser water - four times the salt content of seawater - had something to do with it. Probably both. The main thing is that I proved to myself what I can expect from the Mirage. In combination with my sail rig it should take me just about anywhere I want. And I can't tell you how good it felt to get a good night's sleep rather than spending the night nursing throbbing arms.

There's another island about 20 miles out (40 miles round trip). I'm hoping to make that a destination for an overnighter next year when I've finished upgrading my sail rig.