River run

Being in Minneapolis, we are only a few miles from the Mississippi River, and also close to several others.  It gets tricky in this area because there are a series of locks and dams through here, and there are very few launch areas, but I have definitely been thinking I needed to get out and boat on the river.  With foliage in full color, this seemed like as good a time as any.

I launched from a public area near the Minneapolis Rowers Club boat house.  I headed up towards downtown.  The photo with barge is right at the next lock near downtown.  You can see the very new looking bridge in the middle is a freeway bridge that was replaced after a collapse several years ago - before I had moved.

It was a very nice trip.  A couple barges went by, but because of the locks, not many pleasure craft head up this way.  I definitely like the ease of heading to our nearby lake without car topping, but a little variety is nice too.

If only every day was like this

Calm, clear, and cool.

Not much more I can ask for.

For Sale!

While I would say technically anything I've made is for sale, I'm not necessarily writing this referring to my boat.  I have continued to enjoy taking it out, and I can't believe the leaves are changing, and it will be put away before too long!

Instead, I am writing this because as I design and test components for my next creation, I plan on listing them online in case anyone else with a human powered boat project might want the same or similar part.  It is a chance to advance my own boats while also helping to get more people out on the water.

I don't expect to create any sleek online storefront in the near future.  For now details are here.

If you contact me, I would be happy to discuss whether there is an opportunity for variations or additional designs.  My goal is to focus on parts that are most likely to be common sizes or accommodate the variability of home-built boats and can be shipped with standard carriers.  For example, basic aluminum drive parts and stabilizers (ama/aka) and mounts.  I will be adding more parts to the list as new designs become finalized.

Thanks, happy boating.

Ready to enjoy

Well, the past few weeks have involved building and then working a few bugs out of the new gearbox.  It is a 6.5 ratio using two stages (chain then bevel gear) of the design shown earlier.

It is installed on the boat and I have had a few outings.  I have been trying to tweak the chainline and a few other things to decrease what seemed to be more noise than I was expecting.  I haven't done a full sprint, but it has held up to brisk cruising.

The new prop from Rick is also on and this was  designed for the new gear ratio.  Rick has a mold for steel core, carbon fiber blades, and he is able to adjust the pitch somewhat to accommodate various boats by changing the root angle in the folding blade hub design.  For me cruising has been about 5.5-6 mph at about 72-78 rpm, and I find this to be quite comfortable.  Tiring but sustainable for an outing.

Everything is back together and I have also built a new dolly for walking to the lake.  The boat is balanced with maybe 10lbs to hold at the stern.  I need to watch for potholes, but so far it is going without incident.  I have met a lot of people who are really interested in hearing what it is all about.

I would say I am still quite pleased with the result.  I would also say that now that I have indulged my fascination with steerable props, I would be very happy to go towards a simpler drive design.  I am thinking of tackling an ultra light weight version next, whenever that might be.  Two boats is never enough.

Nice and shiny

Well, the sanding is done and the varnishing is underway!  It is always a really satisfying process to start with the dull sanded finish and instantly see the final result.  I have two coats on and will apply a third later in the week.  Overall, I am happy so far.  It isn't perfect, but I'm getting better.  I only wish it wasn't at the very end when I am more impatient to get it back on the water.

I have ordered the final parts for the new gearbox, and I'll get hopefully make progress on this soon.  The weather has been perfect for boating, but I guess having nice weather for varnishing isn't a bad thing either.

Sanding at last

When I first had the new boat assembled last fall, I knew my warm days were numbered, so rather than miss another week doing the sanding and varnishing, I decided I would wait and do that in the spring.  Well, warm weather is here at last.  I have put the garage back into workshop mode, and I have even taken the catamaran out for a cruise since the new boat was disassembled again.

I have been able to use my fancy new sander.  I also decided to try and hook up our indoor vacuum cleaner as a dust collector, since the shop vac has an oversized hose.  It worked remarkably well, and I'm sure as long as I change the bag when I'm done, it won't be any worse off.

The finish quality should be another incremental improvement over previous boats.  At least I would say the sanding results are an improvement.  I will be varnishing when I return from a trip next week.  Someday I will hopefully get professional quality results, it is a good challenge.  Maybe someday I will even get a spray gun.  Until then my brushing and rolling will only get me so far.

I have also spent some additional time on the drivetrain.  My previous posts showed a few images of a new all bevel gear design.  I would still expect this to be an improvement, but I have moved towards yet another iteration.  This one is a hybrid chain and bevel gear system, but it is still housed in a similar sized box.  The crank arms attach to a first shaft with large ANSI 35 sprocket.  An intermediate shaft has both a small sprocket and a large bevel gear.  This has the advantage of a higher gear ratio, I should hit 1:6.5 with this design.  It also uses a 1:2 bevel gear set which is significantly cheaper than a 1:4 set (enough that the cost of the sprockets is still cheaper overall).  Lastly, this means that the torque on the bevel gears will already be reduced by the chain gear ratio, so this will improve gear life.  With the lower torque, I will likely test a slightly smaller diameter shaft tube (5/8"), and I am eager to test a prop with carbon fiber blades made by Rick Willoughby that has been sized for this approximate gear ratio.

My budget will hopefully be stretched further by doing a greater amount of machining myself.  I have found a local "makers" organization with a shared workshop and inexpensive dues.  This should allow me to do most of the milling myself.  I have found a space with power for my welder, so if I brush up with a little practice, I can do this as well.

Cabin fever and new designs

The lakes might be frozen here for the next few months, but at least the holidays have given me some time to kick around some ideas I might be able to try in the spring.  I get to wait and see how much is in the piggy bank once I'm ready.  I've also been able to watch what others have been up to.  Rick and Mike have both tried new ideas and have had positive results.

I don't expect to do any major work on the hull.  My focus is improving the gearbox stiffness and maximum torque and increasing the drive leg durability with a stronger chain.  I have some new designs worked out in CAD, and I'll think it over for a few weeks before doing anything in case I change my mind.

My original gearbox used a 4" x 6" rectangular aluminum extrusion.  This was oriented so the top and bottom were open and had cover plates.  Under load, the only features to prevent the sides from flexing out were the cover plate fasteners, and clearly this wasn't sufficient.  The new design uses a 4" x 4" extrusion with the fore and aft sides open.  The aft side with the output shaft will have an extruded section welded on as a cover plate and and also serving as a mounting area for the shaft bearings.

The second CAD image shows a cross section with the top cut away.  This shows two additional machine screws positioned as close to the gear interface as possible to provide additional reinforcement against flexing.  The final forward side is covered with a third piece of extrusion sized to nest inside the main housing.  This cover has a cutout for the large gear and is screwed to the housing near the crank shaft spindle.  This should effectively create reinforcing ribs on the side opposite the output shaft.  The crank shaft is also slightly larger diameter and is available as a ground high precision rod, so that I can more easily achieve a tight clearance with the gear.

I am working on new designs for the drive leg as well, although this is not as critical.  I considered various options of using a double chain loop or upsizing a ANSI 35 chain.  However, potentially the easiest option to increase durability is to create a sealed assembly so the chain can be plain steel rather than stainless steel.  The stainless steel chain has a significantly lower strength, but I had chosen it to simplify the design and because the miles I put on the boat shouldn't wear it out anytime soon even if it runs in water not oil.  Production drive legs such as the Wavewalker, use a mineral oil bath to lubricate parts and help prevent water inflow.


The new leg design uses two standard bicycle bottom brackets with machined end caps to house shaft bearings.  I can add o-ring grooves and o-rings to the shafts to seal against the bearing ID.  The top and bottom each have standard tubing welded at right angles and these nest similar as before.  In addition, I can now order steel chain in a continuous riveted loop (no connector links) because the bottom bracket shells are large enough to slide the chain loop on over the sprocket.  The current leg was too tight to allow this and required a connector link.  The continuous loop is rated at approx. 170 lb. working load and this should be more than sufficient.