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. |
8/20/2005
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. |
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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.
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| 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 |
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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. |
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8/21/2005
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. |
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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! |
8/23/05
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.
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8/24/05
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.
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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. |
8/27/05
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. |
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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. |
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8/28/05
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.
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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.
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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.
8/29/05
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.
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8/30/05
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! |
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9/05/05
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. |
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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... |
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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... |
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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! |
9/12/05
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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