Warren's 2005 Human Powered Boat Construction
HPB Construction 2005
I have been gathering parts for this boat for the past 3 years or so. In the spring of 2004 I acquired a twisted chain HPB drive manufactured by Seawind Boat Corp, and in the fall of 2004, acquired a used Necky 19ft sea kayak from Rich Hodgkins. It weighs about 30lbs, and has a Kevlar hull.  The Hydrobowl 2005 HPB races are now only about 3 weeks away, and I have to work hard to get the new boat ready for the event.
Here's my drawing from 2002. The new boat will be very similar to this. I'm going to take the drive unit and slam it into the kayak, right through the bottom of the hull.
I'm hoping that since I sit so low in the boat, and  the drivetrain makes the boat bottom-heavy, I will not need additional stabilization hulls. At low speed or in corners I may need to use a kayak paddle to help stabilize the boat, but at speed the low center of gravity plus the added stabilization of the drive unit "fin" should  keep it pretty stable. On the other hand, the first test rides may be very wet...

Here's the drivetrain I will be using. I obtained it from Seawind Boat Corp. It's made of stainless steel, weighs about 15lbs, and uses 1/4" pitch chain (or it's metric equivalent). It's designed to be filled with oil to keep everything nice and lubed up, and to keep the water out. I mounted some MTB cranks after cutting off the chainring spider.

Here's the cast aluminum prop I received with the drive unit. When I got it, it was painted black and pretty rough from the sand casting process. I sanded it smooth and painted it yellow. This smooth finish should make it more efficient
I'm planning on mounting the drive unit similar to how a dagger board mounts in a sailboat. The unit will be able to slide into the drive well from the top of the boat. This way I'll be able to remove the drive unit when mounting/dismounting, to clear weeds from the prop, or to negotiate shallow areas.

Here's the start of the drive mount that will be epoxied to the drive unit itself.

Meanwhile, out in the barn, the kayak awaits the jigsaw. I will be cutting the cockpit much larger, using the recumbent seat pictured rather than the old kayak seat, and cutting a large hole through the bottom of he boat.
In the interest of expediency, I decided not to use the recumbent seat. Instead, I cut a plywood seat back, and bolted it to the back of the seat and cockpit. Oh, and I made the cockpit a little bigger, to accommodate spinning feet and flailing legs. The cockpit hole was cut to just shy of the front bulkhead.

I measured the boat to find the center of buoyancy, and found it was a bit forward of where the core of my body will be sitting, which is good because there will now be extra weight pretty far forward.

I glued together the drive mount, using epoxy and cotton flox to make a thick glue, then painted the whole thing with epoxy. It's pretty heavy duty already, so I don't think it will need fiberglass reinforcement. The drive unit now weighs 14 lbs.
I built up the drive well box, and temporarily screwed it together to see how it fits. It was too tight, so I added some washers in-between one of the side plates and the spacer boards to give it a bit of breathing room. It's still snug but now I don't have to worry about the drive unit getting stuck in the drive well! 

Lesson learned: When making items that slide together, make the inside measurement of the outer item at least 1/16" wider than the actual inside piece!
Last night I glued the drive well box together with epoxy and flox, and covered it in a coat of epoxy to make it waterproof. Though it looks pretty in wood grain finish, I will need to (eventually) paint it to protect the epoxy, as it's slightly UV sensitive. 
The drive well is all nice and solid now. I sanded off the epoxy flashing and irregularities, and checked the fit of the drive unit into the drive well. Still fits, whew! 

Then, using the drive well as a template, and measuring multiple times, I carefully marked the cut lines for the hole in the bottom of the kayak. I cut the hole with my jigsaw, and it was not too traumatic. I had to make some extra cuts to accommodate the keel rib which actually took longer than cutting the main hole. 

I epoxied the drive well into place and called it quits for the night. 

Right now it's just "tacked" into place, I'll need to use fiberglass, cotton flox filler, and epoxy to make a nice fillet, reinforce and seal down the sides and on the ends. The front of the drive well is epoxied to the deck of the kayak to make sure it's nice and stable. 

Peter Heal of Australia, who also has a couple of these drive units, sent me a note expressing his trepidation over cutting a hole in the bottom of a rowing skull he had acquired to build his HPB. Pete refers to the drive units as "Penguin drives" in a nod to their maker, Chunhong Peng. I think that's a great name for them. 
Glassed in the sides of the drive well. That clearance issue bit me again and I had to spend some time sanding the sides of the drive unit as it fit too tight in the drive well. 

Now that I could actually mount the drive into the boat, I tested the clearances with pedals and shoes. I found that the MTB cranks I put on the drive unit were a little too wide, and had to change them out for some road cranks. I also had to cut out the hull at the front a bit more.

Here's the drive unit actually mounted in the hull. Cool! I need to find some body of water to try it out!

As seen in this picture, the hull of the kayak needs some work. it's a bit fuzzy and white with material sticking through the resin, and has a some rough patch work. It feels very rough to the touch, and leaves my arms itchy when I brush up against it.  I tested and it seems to sand fairly easily, so I will hand sand the entire hull and use the belt sander on the patches to get them as smooth as possible. I will probably find more areas to patch, and will patch the cracks from the inside if possible. If the outer layer of the hull is Kevlar, it will be extremely difficult to get smooth. I then need to coat it with paint or epoxy to bind the fibers in the outer layer and allow a final sanding.

Here's a nice blurry shot of the boat in my dark, dusty and messy workshop.

I worked on the steering. The boat's cable controlled steering was designed so that your feet could control the rudder. I need to change it so that it can be controlled with one hand, so I had to add some pulleys up in the front of the boat, and a cable to complete the cable loop. Without that, a one hand control could only turn the boat in one direction. 

I now need to make the handle to control the steering. I am also making a larger rudder, as I am unsure about the boat's turning capabilities.

After closer inspection, it appears that the hull does have a layer of fiberglass on the outside, and that's what is "showing thread". On the bottom of the kayak, it look like some of it may be worn down to the Kevlar. 

Before making the hull all sticky, I took the boat off the stand and sat in it to figure out where to put the steering lever. I found that the straps used to adjust the foot steering controls will work great to steer with. Sort of like holding the reins on a horse. As long as I don't shout Yee! and Haw! while I'm running through the slalom, it should work out fine.   
Whatever the case, I sanded the whole thing, cleaned up the patched areas and painted a layer of epoxy over the whole thing. I looks much better now, but I can see that there is some roughness where fibers are still sticking out. Hopefully I can hit the whole thing with some fine grit sandpaper and knock that stuff down.

I bought an el-cheapo kayak paddle to use as an emergency balance, turning and propulsion device, but I'll bet the paddle that Dan Grow offered to let me borrow for the races is much nicer so I'll probably use that. Bill Godwin is sending me a couple of Wavebike water leg floats, which I'll probably use like George Tatum did as a fold away balance device, though I don't know if I'll have time to implement that this year. 

The drive unit will be held in with bungee cords, and the cranks are just high enough that when the cranks are parallel to the surface of the water I can unclip. Unclipping while upside-down may be another issue, and possibly one I should practice for. I do know somebody with a pool but don't know how they'd feel about my kayak in it... I think the kayak with the drive unit installed should be self-righting, and if (when?) I tip, as long as I'm wearing a life jacket I shouldn't get more than over on my side. As there is a bulkhead in front and behind the engine compartment, and water tight caps to seal the access holes, even if I do capsize or I get swamped, I should be able to climb back in and pedal (slowly, spash... splash...) back to shore.

Tonight I'll try to sand a small portion of the hull and see if it smoothes down, if not, I have a wallpaper scraper (big razor blade on a handle) that I'll use to knock down the nubbies. I'll probably need to re-coat the hull with epoxy after this work, it only took 6 squirts of epoxy to do the whole hull last time so that's not too bad. 


I sanded the hull a couple times then recoated it with epoxy. Still not perfect, but good enough for this year's races. The epoxy is really too thick to make a completely smooth outer coat, so when I'm ready to make it better, I'll have to sand more, then paint or wax it. 

This nighttime shot in the dark barn shows how nice and shiny the hull is now.

I just need to install the bungees on the drive unit to hold it in in if I capsize and then it will be time to build a cradle for my bike rack so I can take it somewhere to float it!

Dragged the boat out of the barn. Its time to see if it floats. Well it floats in the sea of grass in my yard just fine...
Here's a good shot of the cockpit. I added some rubber edging to protect me from the composite edges of the boat's top. It gives it a nice finished look. You can see the aluminum steering slides up high on the inside of the hull, and the black strap at the rear of the slide that I will use to steer the boat with. Also you can see the bungee cords that are used to hold the drive unit in, in case of a capsize. 
In this picture you can see the steering pulleys at the front of the cockpit. They attach to the steering slides to allow me to pull the straps to steer, instead of pushing the steering pedals. I removed the steering pedals. You can also see that the front of the drive is epoxy/flox/fiberglassed to the top of the hull to make it nice and solid.
Here's the kayak upside-down with the drive train mounted. Plenty of clearance for the prop. I may want to try other larger props in the future...
Speaking of larger props, here's a blade (mold) for a sub-prop designed by Charlie Ollinger. Garrie Hill will be building a prop from this mold. Interesting...
Ok, enough digression! Build the bikerack HPB adaptor! Put boat on car! Take car to pond! Float boat! Pedal forwards and backwards, no room to turn! Whoa, be careful not to tip over...
Well, here I am still dry, but the boat is pretty tippy. I don't think I can pedal like a madman and not capsize without a lot of practice. Since I don't have a lot of time, I set up the training floats that Bill Godwin sent me (Thanks Bill!). They are mounted on the seat brackets and can be raised and lowered. I hope to be able to run with them out of the water most of the time, but can lower them if I need more aggressive balance control. I'm ready for Hydrobowl 2005!
Hydrobowl 2005 has come and gone. Saturday morning, HPBers began to show up at about 8:30 am and were busily carting their boats down to the lake and putting them together. The day quickly turned sultry and even on the lake, the sweat was flowing without provocation. We reached critical mass at about noon and the races were started. 

The new Necky HPB performed well, and I raised the floats as high as possible as it didn't seem to take much to keep me upright. The new boat was definitely faster than the Sidewinder, but did not turn well. That was not surprising as I was using the tiny stock rudder. I'll make a bigger one for next year. Also the straps did not work out well for steering, I need to rethink the steering controls for next year. The drive unit performed well, and was very quiet. I ended up having to use the floats to help me steer in the slalom and 2K race. The seat ended up being the most limiting factor, as I was too upright, and too close to the pedals to do a good sprint (my fastest 100 meter sprint was 26.50 sec). I ended up with some nice bruises on my back from pressing the middle of my back into the seat. 

Jake Free came in 1st place overall again and won the 2K race This year Dan Grow pulled an upset by winning the 100M sprint in  an incredible 22 seconds, and came in 2nd overall. Paul Niederman came in third overall, winning the slalom, and turning in respectable finishes in the rest of the events. I was 4th overall winning nothing, but I did come in 2nd in the 2K race. Bob Buerger got his tandem catamaran together and had a fast 24 second 100 meter run with Len Brunkalla before destroying the drivetrain, then raced his single HPB for the rest of the event. Dan Roche showed up with a new Catamaran with 10 foot hulls and a very nicely machined drivetrain built using extruded aluminum channels. He had some issues he was able to resolve during the races, and others like his small rudder and too short 10 foot hulls that he vowed to have resolved for next years races.  Full results soon.

After the races I removed the floats and rode the boat around a little without issue (I didn't get wet!). It is much more stable at speed than when stopped, so next year I'll just use some floats placed up high enough that they will not contact the water unless I am tilted waaaay over. That should speed me up a bit.

We finished the races before dark, cleaned up, and made our way to the Thai restaurant for dinner and announcement of the Hydrobowl overall results


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