Human Powered Ocean Crossing Boat Design

Introducing the CapCat

anti-capsizing, wave isolating, energy generating human powered boat.

Here are some video views from the front, and the rear

It is driven by a prop and pedals and rides on two catamaran outriggers. Ocean swells and waves from the side are absorbed by the pivoting outriggers keeping the cabin and prop level. If ocean conditions are severe, and the vessel capsizes, the outriggers simply rotate around the cabin and swap positions with the lower set of hulls. The constant rocking action can turn an electric generator to store power for radios, water maker, and other misc electronics.

An alternate version of this concept is to use three triangulated hulls rather than four:

A higher resolution version of this animation is here

And a third version of this concept is to eliminate the third hull and in the event of a capsize, one hull section can be manually rotated back into the water. A serious technical problem to this approach is that once the hull has been rotated back onto the water, it would need to be rotated further to lift the heavy cabin up and then locked into place to match the original geometry. I'm not sure how the operator would lever his power to lift the entire boat up 2 or 3 feet. This animation shows a capsize, but does not show how the lifted hull would rotate back into the water.

Possible Advantages:

1. Narrower catamaran hulls may be more efficient than a single mono-hull featured on traditional ocean rowing vessels due to far less displacement. According to a study by The International HISWA Symposium on Yacht Design and Yacht Construction, they found that the most efficient hull design for a long distance water bikes is a catamaran or a slender mono-hull. The traditional ocean rowing boat is a mono-hull, but most probably not a "slender mono-hull".

Further evidence that multi-hulls are more efficient than single hulls is the fact that all longer distance human powered boat speed records have been set with multi-hulled boats.

2. Because the catamaran hulls rotate around the main cabin, the cabin will never capsize.

3. Because the cabin won't capsize, this design does not require a heavy, draggy keel or center board thereby improving efficiency.

4. Vastly increased comfort for the operator due to some of the rocking motion being reduced by the pivoting cabin.

5. The electric power generation from the rocking motion of the catamaran hulls around the main cabin could eliminate the need for wind and/or solar generators.

Possible Disadvantages:

1. If the constant movement of the pivots combined with the harsh sea water environment were to corrode or damage the pivots, then the main cabin could flip over with a capsize, and power generation would stop. This could be resolved by ensuring that there is a over-ride mechanism to turn the cabin manually in the case of a pivot malfunction. There should also be some form of power generation back-up like a solar panel or wind generator.

2. The force of the hulls hitting the surface of the water upon a capsize could damage the hulls, struts or cabin - especially in the case of the quad hull version.

3. The aerodynamic drag of this design would be greater than a traditional mono-hull because there is more surface area exposed to the air. However, at typical speeds of a few knots, aerodynamic drag is a very small factor unless powering into a stiff head-wind. Because the cabin and one or two catamaran hulls are up in the air, the wind could catch it and blow it over causing unwanted hull rotations. This risk is greater with the tri version than the quad version.

4. The weight of this design would probably be greater than a traditional mono-hull and could be slower and less efficient because of this.

5. It is possible that with the drag of the prop and strut, an ocean swell would rotate the main cabin section almost as much as the catamaran hulls are being rotated thereby negating much of the wave isolating pivot effect. The side profile of the prop strut should be as hydrodynamic as possible to allow it to slip sideways through the water.


Rick Willoughby wties:


I will make sure I give you dimensions in British units. 600mm is

only 2 feet. A narrow hull. Just wide enough to get the shoulders

into. The boats I build are just over 1 foot wide at the waterline

but they are only intended to displace 200lb or so.

The stability is a matter of getting the weight low enough and having

buoyancy up high. A sphere with a small weight on the surface will

float with the weight down. The boat I am thinking of would have an

offset ellipse X-section at the cockpit. A rounded bottom coming up

to a beam of 2 feet at the waterline, a little bit wider above the

waterline to give shoulder room and then narrow above the shoulders

to take in the head.

When you are in the ocean the water is rarely level so a boat that

relies on gravity for stability rather than hull form is often

better. You could set your drive leg up to get weight down low to

help with stability. You may even add some ballast below the prop.

It would also be handy if you can lift the drive leg out of its well

to inspect and work on. Something like Warren B has done with his

Necky Kayak.

You would need to strap into the seat in rough weather so that if it

rolls you stay in the right place. For sleeping you collapse the

back of the seat. You are then even more stable because the weight

is lower. Again strap in so the boat can do a complete roll without

you smashing the canopy.

I am not sure if you are aware but sailing monohulls are normally

designed to have a positive righting moment throughout a 360 degree

roll (apart from the 180 position). Some modern ones with flat decks

are stable upside down and this is a safety issue. The small boats

in the Sydney to Hobart ocean race might roll through 360 degrees up

to 4 times in a race. The bigger boats often destroy masts if they

suffer a complete 360 but they usually get upright and stay afloat.

I am certain that if you continue with this adventure you will be

thanking me that I talked about righting moment and it is a design

feature of your boat when you are facing 5m cresting waves in the

middle of the night 1000km from anything. You need a very large

multihull to feel secure in such conditions.

The boat would be built for speed and is not intended for lounging

around. It is intended to work well IN water and not designed for

sitting ON the water.

Another advantage with pedal power is that you do not need to operate

a paddle over the deckline. In fact you can site below the deck. If

the deckline of kayaks was made higher then you would start to

improve stability. It becomes more like a Canadian canoe with high


I have attached a sketch of this concept. The proportions are not

correct but you should get the idea.

Draw it up and seek comment from people on the IHPVA boat site. I

think it will look fast. The hull needs to be about 500mm wide at

the crank so you have clearance for the pedals and heels.


Stevie writes:


A word about your designs. Lovely ideas. Having pedalled 6,500 miles on the ocean I look at the idea of remaining so beautifully stable with great envy!! I'm no design expert, so Alan Boswell or another marine architect's opinion is more valuable than mine, but my two pence-worth of advice is to keep it simple. Build a nice sleek, strong monohull, enclose yourself inside a cockpit you can seal but also give you plenty ventilation when you want it. Pedal power beats rowing power every time - I'm sure you'll be able to beat any rowing record over the same route. Use bearings and solid shafts to transfer power from feet to prop - not chains. Build a stainless steel version of the MicroMarine units we used, so you can easily replace and repair. Monohulls are horribly tippy and uncomfortable, but a self-righting monohull desgn is safest bet for you. I assume you want to do the northern route from Newfoundland, 2,000 miles. The North Atlantic is cold and the weather can be bad, even in summer. Have a very supportive custom-built pedal seat with racing driver seat belt, and a place to wedge your neck and limbs in tightly to sleep.

The ocean is a terrifyingly powerful place, you can't stop, you can't get off if things go wrong. When I look at your design I see a lot of windage to slow you down and make it hard to steer, I see complicated engineering, three right-angled changes in direction of power to get to the prop, and a lot of elements that could snap or seize up and be extremely difficult to repair at sea. Also I see your prop being out of the water as much in it.

In essence: minimize windage, keep your design low in the water, round heavy hull and light tapering deck and stores stowed low for ballast - all this will ensure self-righting safety. Monohull, enclosed cockpit, all-in-one pedal replaceable units to fit into a central well - thus power delivered midway along hull.

Cheers, Steve

And rich writes:

The ladybird is a nice design. I would say the hull has been

optimised for the speed the rower can sustain in good conditions- say

5mph. It would be difficult to maintain that sort of speed once it

gets a bit rough. The average speed will depend a lot on the chosen

route to take advantage of wind and currents. AND some luck that the

weather is kind.

The concept I have sketched should be possible of sustaining maybe

5.5mph but I would need to check this based on the actual

displacement you think you will need. However the proposed design

should not be bothered by sea conditions as much as ladybird so you

can sustain a higher average. The concept would move very fast in a

following sea with very little effort.


I had anticipated question 1. See previous email.

Regarding question 2. The boat needs to be able to stay afloat and

upright if swamped. It could be made to be self-bailing for the most

part through the open well for the drive leg. It is also a good idea

to have a closed well low down in the hull that collects condensation

and can be pumped out. The whole hull needs to have clear drainage

to the low point. You get a lot of condensation at night after a warm

day so things get wet and uncomfortable if they do not drain.

The 22" width is at the waterline so you can go wider than this above

the waterline. It would be borderline to have it stable enough to

walk around on. I think the idea of an outrigger that deploys from

one side would make life a lot better. It could actually be part of

the bow or stern fairing when folded away. It could have some

netting so you can sit on for washing and calls of nature.

It is surprising how little clearance you need above the waterline in

the centre of a boat to avoid having water come in. I expect you

could operate with the cockpit open for maybe 80% of the time

depending on the chosen route. You would need to have good weather

forecasting to leave the cockpit open while sleeping.

Your body weight will be part of the ballast. The ends of concept 1

get narrow very quickly and you do not want to widen above the

waterline in the ends to allow for sleeping. I would be thinking

about a retractable or folding seat to provide a nice bed.


3 Responses to “Human Powered Ocean Crossing Boat Design”

  1. # Anonymous Tom Lynch

    Hi Greg...
    I am enthralled by the concept of pedaling across an ocean. Having been involved with ocean rowing for many years I am concerned about your design however.
    I met Steve and Jason with Pedal for the Planet before they left Sausalito to pedal the Pacific. Moksha is an amazing boat.
    I was also the webmaster tracking Nenid Bellics fatefull row where he was lost at sea off the coast of Ireland. Similar design to Moksha with a closed cockpit; somehow he capsized, boat filled with water, wasn't able to self-right...tragedy.
    Another rower with a small craft with a closed cockpit Aussie Andrew Mcaully was lost at sea recently after a 1000mile row within sight of land. Small boat, closed cockpit...he had many problems.
    I think your boat design is too small. You need to be able to stand upright and flex a bit. I also think a monohull is not a bad idea. You need a larger cabin; more storage. All the requisite saftey gear required by the Spanish authorities would be hard to store on you boat. I am a big fan of open cockpit.
    Anyway enjoyed reading your website. Your curriculum Vitae is remarkable. With the right gear I think you could retrofit one of the standard ocean rowboats and still break the record!!

    Good Luck
    Tom Lynch
    American Director
    Ocean Rowing Society
    Guerneville, California  

  2. # Blogger Adventures of Greg

    Thanks Tom - what is your email address?

    I am familiar with what happened with Andrew, as I was following his closely during his Tasman crossing. Also with Nenid - That must have been difficult for you to be part of that team.

    Also note that Emmanuel's row boat capsized and filled with water during his recent crossing race and he was rescued within 15 minutes.

    I believe the problems with these boats, or the circumstances of the accidents were that the front and/or rear compartments were (or may have been) open at the time of the capsize. It is my intention to never leave the front or rear compartment open. If a capsize occures, the air trapped in both the front and rear should right me even if the main cockpit were to fill with water.

    Also - (and this is very important), since my angle is more of a technology/human performance one, it is my intention to travel WITH a safety boat.

    One of the reasons i am building a PROTOTYPE boat (Within), is to test some of your concerns out in real conditions. I will learn a lot from that!

    Greg K  

  3. # Blogger Mark Benton Karlsvogn

    Hi Greg

    Why not use hydrofoils?  

Post a Comment

Subscribe to email updates:

Email :

About Greg video:

    follow me on Twitter

      Adventures of Greg Home
      Motivational Speaker

      featured slide show:

      Archives (newest first)

        Web This Blog

    © 2006 | PedalTheOcean BLOG by Greg Kolodziejzyk.
    motivational speaker
    No part of the content or the blog may be reproduced without prior written permission.