View Full Version : Hello from Mastic, Suffolk County

08-25-2009, 09:47 AM
:o) Hi, my name is Jorge. I'm looking forward to getting my first welder soon and going Rambo on my first project. I've decided to build the Kyoto Cruiser for my daughter and I. Jacqueline is autistic and this will be a special project, once the build is done our family will be able to ride together. Once that's done, the Warrior is next. I also live near the water, so I am trying to figure out how to build a folding, tow-able; catamaran. I want something to strap my current recumbent onto and go water biking! Guess I better learn to weld first!!!

08-25-2009, 10:39 AM
Hi Jorge and welcome! You'll fit right in here.

08-25-2009, 05:45 PM

The folding part of the catamaran is easy, the towing part is easy, the powering of the catamaran is easy, it is just making the cataramaran that is the harder bit :boat:

Looking forward to the progress reports and pics on this one!


08-25-2009, 07:10 PM
Welcome Jorge! I'm about an hour away in Baldwin, Nassau County. Richie Rich is in MA now, but hails from Queens.
I've also been kicking around the idea of a bike/boat for a few years now. The beauty is, since it's human powered, it doesn't have to be registered. The challenge is getting components that are impervious to salt water, unless you plan on sailing in fresh water only. Out there in Suffolk, I guess there are some lakes and rivers, like Lake Ronkonkama. Here in Nassau, there are no fresh water bodies that allow boating.
When I was a kid, we added some wheels and hand cranks to a kayak, which worked well for a while, but even after thoroughly rinsing everything and drying with a hair dryer, the steel components only lasted a couple of months. Nowadays, there are a lot of stainless steel and aluminum components available, so it may be more feasible. I'm thinking maybe alloy hubs with sealed bearings, and replacing the bearings and axles with stainless. I've been looking for a stainless freewheel and rear derailler, but haven't found any. There are stainless chains and aluminum cranksets, so at least that's half the battle. A better solution might be to use a belt system. there are some good ideas on the Net, if you look around. Google human powered vehicles, and human powered boats.

09-01-2009, 08:23 AM
Hey Peter T, if you see this post-it turns out I'm kinda stuck figuring out the folding part. I have what I think is a decent drawing so far, but no idea how to fold it yet.
Kidd, if you're interested we can swap ideas. It would be nice to have someone close by as a sounding board.
Thanks for your replies, finally nice not to get the "He's crazy, you know!", looks!!.

09-01-2009, 09:31 AM

The folding part is simple....

Work out how far apart you want your hulls, then make a simple hinge joint in the centre of the distance, and two similar hinges close to the hulls
The central hinge should fold up, yet have clamps over the hinge, so that when locked in the extended position, and the retracted position the hinges can't move anywhere.
The outer hinges should also have a cage that allow the outriggers to be locked in the open & closed positions.

If you mount your trike rear wheels on a set of rollers, which in turn are connected to a chain drive, connected to a chain-driven propellor, your forward pedalling will rotate the rollers, and drive your propellor, pushing you forwards!

Your front wheel rests in a support frame that operates the steering on the catarmaran, so everything that functions on your trike (quad) will still function out on the water! Apart from the brakes being an anchor :jester:

For towing, see this thread

For drawings of this idea, see below

Any more questions, send 'em this way! Looking forward to seeing it afloat! :boat:

Email me your drawings, if you like: tremlett@emailaccount.com

09-01-2009, 09:57 AM
Further refinement to idea!



09-01-2009, 04:32 PM
Pontoons sounds like fun for the most part. But here in Florida you share the water with other players ... like snakes & gators. Not the friendly playmates that you want to share a ride with.

Lunas'Harold :sunny:

09-01-2009, 04:44 PM
So make the hulls out of clear polycarbonate plastic, you know the bullet proof stuff, they can't see your hull till you have past them, and you get to see them as you pass them, through the hull! Mobile aquarium, trike & boat all rolled into the one nice lil' toy!

PeterT :boat:

09-01-2009, 04:47 PM
Here is what I have so far. I would like the pontoon frames to fold where they meet the center frame.

09-01-2009, 05:10 PM
Hey Peter,
The clear pontoons is a cool idea. A while back I found a website with instructions on how to form a wind screen for a recumbent. I think it would be adaptable for forming boat hulls around a form. It involves building a shed that retains heat and using BBQ gas to heat a plastic sheet mounted in a frame and hung in midair. Too involved for me to try, tho.

09-02-2009, 02:19 AM

Your design looks good, any chance of seeing the side/front views as well, make it easier to get the bigger picture.

You should couple both sides of the roller to drive your paddle wheel to share the load on the axles, then you could use rubber v-belts and v-pulleys to drive the rear wheel.

The folding bits would be exactly as I drew them, only make the centre pivots at the edge of trike support frame, and the outer ones just inside the outside edge of the pontoon, so that the pontoons remain square to each other for transport, with the main frame and your total transport on road width being an inch or two less than half the extended width of the total boat.
That would also lift your rear paddlewheel above the pontoons for land transport.

Mount some wheels inside your hulls, and you could roll into the water or drive out of the water.

Make your trailer hitch removable, by mounting it to a brace bar that would go across the folded uprights, and remove when the cat is prepared for water.


09-02-2009, 10:03 PM
Workin' on the side view, I'll post it when done. The paddle wheel is actually supposed to double as a transport wheel. I figured to use two bike wheels and pop rivet aluminum sheet metal to the spokes for paddles. Now that you mention it tho, I should mount two caster wheels up front for launching.

09-03-2009, 01:15 AM
Made a few improvements in the original drawing, and a quick and dirty three quarter view. Didn't draw it in, but I like the idea of dual belt drives.

09-03-2009, 02:35 AM
Looking good Jorge, any ball park measurements yet, or just drawing it as you think will work? :boat:


09-04-2009, 08:12 PM
Hi Peter,
I drew this using Inkscape, (free download). I actually did measure out all the parts, but didn't label it 'cause I can see the measurements with a mouse click. Here's one with measurements-much more useful for you!
I based it on the dimensions of a flotation billet. (http://building.dow.com/na/en/products/specialty/billets.htm)
I've been trying to decide whether to shorten the length, and if I want to make it a totally amphibious vehicle; rather than tow-able.

09-04-2009, 08:14 PM
Oops, helps if I include the drawing!!

09-04-2009, 08:21 PM
Actually, I wonder if the Kyoto Cruiser would make a suitable platform. I plan on building one anyway....

09-04-2009, 11:29 PM

Looking good so far!

???? how many people are you intending to carry ????

If you are only wanting maximum of two people, then the Kyoto may be the way to go, however, if you build a floating Kyoto, and only have one operator, you must be aware of the load imbalances that you have now created, all the weight will now be loaded onto the driverside pontoon, causing your cat to go in circles!

Whilst the Kyoto is balanced on the ground, there are soooooo many more variances once you take a stable road vessel and put it onto a moving , floating structure.

A Kyoto would serve the purposes well, you would just have to make the pontoons fold up or be detachable, so that you can ride on the road once you have finished :boat:ing


09-05-2009, 12:30 PM
Ha ha!
That would be hilarious if it wasn't happening to me! Seriously tho, it does bring up the issue of one rider/two drive trains. Unless I use the method previously mentioned in another thread for "positraction", or maybe just tie the pedals together.Probably would have to do that, anyway-unless I also arranged for two waterwheels or propellers. The rudder should take care of the imbalance caused by one operator. Still, it would bug me. I'll stick with Plan A for now... Speaking of propeller, how hard do you think it would be to set that up vs water waterwheel?

09-05-2009, 07:07 PM

For your waterwheel, take two 20" front steel rims, or if you can get them the plastic BMX rims, place in a holding device, at the required distance, and then join the rims with equal lengths of either rod or timber... use steel rods to weld to the rims and attach your water scoops to them, or use timber runners to join the wheels together, and fit your waterscoops to the slats.

Make a couple of flanges to attach to the outside of the joined rims and mount your drive line to those.

Have a read through all the threads here, I do several times daily!, there is so much wealth of information here. Also read where I have typed how I am setting up the gearing on my Downunder F-RQ (Fast -Recumbent Quad), as I have a centreline drive line, driving two secondary axlesvia a live axle.


Odd Man Out
09-05-2009, 07:43 PM
Have a read through all the threads here, I do several times daily

Amen to that -- so I am not the only one addicted to this forum!?!?!

09-05-2009, 07:45 PM
My order of reading:
AZ forum
books on leadership


09-05-2009, 11:56 PM
I will track down the thread of which you speak. Out of necessity, tho, I have to try to make this as simple as possible. I don't have a lot of room or tools to work with. I consider that a good thing. Simpler design will make it less prone to breakage at the wrong moment! I've already decided to use 1x4's instead of 2x4's; and glue them into the tops of the hulls, rather than the sides. You gave me an idea for the water wheels. Just span aluminum between the spokes, fold the edge over a spoke on each side; and pop rivet the metal on. I would love to find pulleys made for toothed belts at the junkyard, so they don't slip when wet. I can also narrow the center section from 2ft down to 1ft, and shave about 5" off the beams to the hulls.

09-06-2009, 06:37 AM

To give you an idea of what can be built in a smallish area, may I present my work space:




and this is from inside the garage


09-06-2009, 09:38 AM
I will track down the thread of which you speak. Out of necessity, tho, I have to try to make this as simple as possible. I don't have a lot of room or tools to work with. I consider that a good thing. Simpler design will make it less prone to breakage at the wrong moment! I've already decided to use 1x4's instead of 2x4's; and glue them into the tops of the hulls, rather than the sides. You gave me an idea for the water wheels. Just span aluminum between the spokes, fold the edge over a spoke on each side; and pop rivet the metal on. I would love to find pulleys made for toothed belts at the junkyard, so they don't slip when wet. I can also narrow the center section from 2ft down to 1ft, and shave about 5" off the beams to the hulls.

grab a couple of timing belt pulleys from the junkyard. The early toyotas and datsuns have good pulley's to loot.

09-06-2009, 07:42 PM
Peter, that is one very tight work space!
Macka, thanks for the tip.
I am currently starting yet another redraw of the cat.
New information has arrived via the web!

09-09-2009, 04:56 AM

Take your drawing, and on the front view, draw a parabola from the outside edge of one float, to the outside edge of the other float, and then mark the centre point.

Then go to your side view, and mark another parabola from the shape of the front of the float to the shape of the rear of the float, and then mark the centre point.

Transfer both centre points to the decktop plane, and mark it as Bouanacy Point (BP).

Next figure out the Centre of Gravity (CoG) for the trike unladen/fully laden
see http://www.jetrike.com/why-does-tilting-matter.html for more info on CoG.
Printed below for all to read.

For non tilting trikes the rider Center of Gravity (CoG) must be low, and the track (the distance between the contact patches of the two outer wheels) must be wide, certainly much wider than the profile of a standard bicycle and rider. The reason for this is dynamic stability. For a non-tilting trike to be safe, it needs to handle corners at normal speeds without the risk of rolling over. If however you wish to construct a trike with a narrow track and/or high seat, then the only way for it to be dynamiclly stable is to make it tilt.

What causes a non-tilting trike to roll? Well, it turns out that there is an optimal (safe) place where the rider CoG on a trike should be.

Calculating optimal CoG

Looking down from above, if we draw a triangle between the three contact patches and at the mid point of each line we draw another line to the opposite corner, then the intersection of these three lines is the optimal point where the rider CoG should be.


Calculating the lateral tipping point

Now looking from the front, if we take the track measurement B and we divide it in half we get A. We use A to construct an isosceles triangle between the contact patches. This triangle represents the tipping point for the trike. If the CoG is inside the triangle, then the trike will skid when it looses traction while cornering, if the CoG is above it, the trike will tip.


Calculating the longitudinal tipping point

You can also draw a similar triangle on a side view of the trike using the wheelbase measurement for B to derive A. You can then use this side-on triangle to calculate where to place the CoG in order to prevent the trike from tipping forward when breaking -- more of a problem for tadpole configurations.


Calculating the actual tipping point

The previous two calculations would be fine if the CoG on either axis was directly between the two wheels, but its not. The optimum place is 1/3 of the wheelbase length back from the isosceles triangle's base. At this location, the triangle is only 2/3 of the track width.


The optimal CoG tipping space

Now we use this 2/3 track measurement as B to derive A which is 1/3 of the track width. We then use A draw a vertical line up from the optimal CoG point. We then use the point at the top of this line to create a three sided pyramid. This pyramid represents a 3D view of the tipping space, inside which the rider CoG must remain for the trike to be stable.


Optimal CoG simulation

This simulation confirms the theory (download the Juice file here). As you can see, on a non-tilting trike you end up needing an very low seat or a very wide track to keep the rider CoG inside the tipping space. Find out about running Juice simulations here.



09-09-2009, 04:56 AM

Sub-optimal CoG simulation


Spend any time playing around with this simulation and it soon becomes clear that raising the CoG by as little as 100mm has a big impact on handling. Raise it by 200mm to 500mm -- the CoG height you would end up with if he seat height is 250mm and a trike with a relatively narrow track of 700mm becomes seriously dangerous!

If you want a trike with a higher seat and/or a narrow track, then you have a problem, you simply can't take corners at full clip without tipping. However if the trike tilts you can have a higher seat, because even though the rider CoG may be above the pyramid, as long as the CoG leans to the inside of the outer pyramid plane as it corners, the trike will be stable while cornering. Paul Sims parallelogram based leaner (pictured above) was able to out corner other non-tilting trikes competing in a 24 hour OzHpv event.

Banking angle under uniform circular motion

This leads to another factor to consider in all this, the banking angle. It turns out that objects under the force of gravity have a constant banking angle at speed regardless of the objects weight. The formula above is used to calculate this angle. v is the velocity (speed divided by time), r is the corner radius and g is gravity (9.8 m/s2).


Using the formula, this first graph plots this banking angle as a product of speed. The lines in this case represent the corner radius in meters.


Using the formula, this second graph plots banking angle as a product of corner radius. The lines in this case represent the speed in kph. You can download the Excel spreadsheet here.


On any trike, if you construct the frontal triangle described above using the actual rider CoG (assuming it is above the tipping point) and measure the angle from the outside contact patch to the rider CoG, you can look up this angle in these tables and derive the maximum speed on a particular corner radius the trike can handle without tipping over. Depending on the grip and surface, a tire will generally loose traction at around 45 (1g), so angles beyond this are meaningless.

This of course assumes that the road you are riding on is actually flat. In my area many of the arterial roads are properly engineered, so all these calculations have been used to grade these roads. You can turn a corner on a properly banked road at the posted speed without needing to tilt at all. But they are a double edged sword. When you ride fast down hill a banked corner is helpful, but when you ride slowly up hill, a banked corner is a nuisance. Its one of the many reasons why tilting should always be independent of steering."

Once you know the CoG of the trike, then calculate the CoG for the boat, and then super-impose your trike's CoG over the boat's CoG and superimpose these over the boat's BP and you will see if your vessel is stable or not.

Then change things till they align with each other


John Lewis
09-09-2009, 09:14 AM
I think Julian Edgar has done some articles on this . May find them if you search this site.


25 Hz was extolling the virtues of leaners on this forum a little while back. He was having great success with one based I think on the Sims design. Certainly helps stability. I've seen a trike motor scooter round here with 2 close together front wheels. It is a leaner.

John Lewis.

09-11-2009, 02:04 AM
Holy cow!
That's some technical stuff, but I'm game. This stuff gets deeper and more interesting than I thought. Don't blame me if my wife comes after you guys! I have to build a scale model and test for stability, but the COG material is a great head start...

09-27-2009, 07:22 PM
Well if your wife comes after me, make sure you get to carry the bags,....
'cos I live in Australia!


ps. how is the model coming along?

Dr. Smooth
12-03-2009, 06:39 AM
Jorge, do you have your welder yet? I could give you a welding lesson to get you started. I live right by you in Mastic Beach. Some Saturday morning would be good.

12-03-2009, 07:00 AM

How is your Aqua-Firma :boat:cat coming along ?


12-05-2009, 06:51 PM
To Peter T:
Hmm, now that you bring it up; I think StreetCat would be a nice play on words. I don't want to start on that one yet, I still need to get some welding time under my belt. When I start work on it tho, I will definitely let you know.

To Dr. Smoothie:
Thanks for the offer. As a matter of fact, I just got the welder. It would be great to benefit from your experience, and I think having someone nearby to talk "shop" with would make the builds more enjoyable. My first bike will be the Kyoto Cruiser, then the racing trike.


12-05-2009, 07:22 PM
How about KyotoCat?
or Catyoto?


Dr. Smooth
12-10-2009, 12:42 PM
I have many years of welding and fabricating experience and will help you out. let me know and I'll show you one Saturday after the holidays. If you got a MIG, use 90% argon and 10% CO2. Pure CO2 gives very good penetration, but too much spatter. At work, we use 75% argon and 25% CO2. It is a pretty good compromise because we weld thick angle a lot. The 90/10 will be great for nice clean welds on thin tubing. Use .025 wire so you don't burn through so easily.

12-14-2009, 11:29 PM
Nothing fancy, just a stick welder from Harbor Freight. I like the sparks. Oooh, shiny.....