Human Powered Ocean Crossing Boat Design - "Concept 1"

Human Powered Ocean Crossing Boat Design - "Concept 1"

I started with a traditional ocean rowing boat model from the FreeShip application:

I removed the angular top section and scaled the boat to 24 feet long x 24.5" tall including a rounded top (top is just below my eye level). A removable canopy with a clear dome takes to total height to 34". I also added a seat, pedaling station and retractable outriggers:

This image shows the outriggers in the retracted position. The purpose of the outriggers is to provide
more stability when standing up or moving about the boat. The normal position when I am sitting in the
pedal station, or sleeping is retracted as shown above. The buoyant outrigger hulls in the retracted
position should also assist in up-righting the boat upon a capsize.

This image shows the outriggers in the extended position. This configuration is for when I need to stop
and attend to other duties aside from peddling - like standing up, moving about the boat, preparing meals,
performing maintenance, bathroom, cleaning, etc. A net could be strung from the main hull to one of
the catamaran outrigger hulls.

Since the boat is less up-rightable with the outriggers extended, the outriggers should only be used during
relatively calm conditions. If the boat were to capsize with the outriggers extended, the mechanism for
retracting them should allow for underwater operation. I would envision a rope, pulleys and hand-crank
type of mechanism for extending and retracting the outriggers (like the mechanism used for sails).

This image shows the canopy top in the retracted position. Note that this current design does not allow
the canopy to be open while the outriggers are retracted, which is something that needs to be re-thought,
as I would want to be able to sit at the pedal station with the canopy open AND outriggers retracted.

This image shows one option for compartments. The rear compartment is water-tight when the door between
the rear compartment and the pedaling station is closed. This could be used for some equipment and supplies
storage as well as sleeping. A disadvantage of using this configuration to sleep, is the inconvenience of having to
open the hatch to look out for ships through the bubble.

The pedaling station would be water tight with the canopy top closed, and could have drain holes for allowing water
to run out when operating with the canopy top open. If the boat is being operated with the canopy top open,
it would be important to make sure that both hatches to the forward and rear compartments are closed and sealed,
in the event of a capsize.

The forward compartment is water-tight and accessible through a hatch door. This would be where most of the
food and equipment would be stored.

I wonder if the entire rounded top section of both the rear and forward compartments could be sealed-off and air-tight
for extra capsize proofing? It would be advantageous to be able to use the rounded top as head-room for crawling into
these compartments.

This image shows a different sleeping configuration. The advantage of this is the convenience of getting up
during a sleep to look through the bubble to look for traffic. There is also more room to sleep. The disadvantage
is that is the pedaling station is allowed to get wet when pedaling with the canopy top open, water would get
into the supplies and equipment in the rear. The far rear (back from my feet) could be enclosed in a separate
water-tight compartment. I think sleeping configuration A would work better because it would ensure that the
sleeping area is always kept dry. Perhaps a second small bubble could be placed over the rear sleeping
compartment, or some small windows in the rounded top.

This animation shows 2 ways in which the outriggers could extend and
retract, along with how the canopy top would retract.

Top view canopy retracted

Top view canopy in place

side view outriggers retracted, canopy in place

side view outrigger extended, canopy retracted

Concept 1 - monorigger

The dual outriggers may be more complex than this stabilizing system really needs to be.
This concept uses one single outrigger hull that extends with a swing arm from behind
the canopy bubble. Operation of it could be ropes, pulleys and a hand crank.

The animation shows how the mono outrigger swings into extended position
via the swing arm.


I didn't add a rudder because I wasn't sure where it should go.

3 or 4 solar panels could be fastened along the rounded top at the nose and the tail.

I am creating a list of supplies and trying to get an estimate of sizes, power requirements and weight.
so far, following is a table of supplies and equipment what will be required.

Estimated weight:

Leven Browns supplies weighed 595 pounds (150 days).
Tinys boat + supplies weighed 2000 pounds (100 days)
Around-n-overs boat weighed 550 pounds with 770 pounds supplies and 330 pounds of ballast
Fedor Konyukhovs boat weighed 771 pounds and 1100 pounds for supplies (this may include water ballast?) (4 months)
Zeeman Challenger boat weighs 880 pounds and 1325 pounds of supplies (9 months)

Electronics Other Safety Emergency grab bag
lap top (Panasonic Tough book) freeze dried food for 75 days lifejacket EPIRB
backup computer
(hand held device like pocket PC)
tookkit + small spare parts safety harness & line strobe flashing light
Satellite Telephone (voice and data) spare drive unit EPIRB signalling mirror
VHF radio water maker medical kit whistle
backup VHF radio back-up watermaker liferaft foil blanket
batteries sea anchor emergency water 2 flares
solar panels compass flares 6 light sticks
solar panel controller sponges oars knife
Sea Me Radar Transponder clothing fire extinguisher small compass
fixed GPS navigation lights fire blanket flashlight
backup GPS (hand held) water containers throwing line 2 bottles water
backup GPS (2nd hand held) eating containers and utensils signalling mirror chocolate
battery monitor cooking gas (propane)
mini first aid kit
video camera navigation charts
emergency fishing kit
still camera mask and flippers

iPod extra foam padding

spare iPod seat and sleeping harness

satellite radio camelback/water bags

amp and speakers epoxy and fiberglass repair

spare headphones, earbuds


Argos beacon

small hand axe

Radar reflector (activ-echo) flashlight

fishing kit




cooking stove

back-up cooking stove

sleeping bag - blankets

matches, lighter

Ocean Rowing Statistics

Number of attempts to cross an ocean by rowing: 275

Number of completed voyages: 176

Number of rowers lost at sea: 7

Risk of death: 2.5 %

Risk of failure: 37 %

Project Plan:

I think my steps are as follows:

1. Continue to refine the 'rough' design of the vessel as per Ricks suggestions

2. Continue to refine the specifications that the vessel needs to have (equipment list and weights, performance expectations, etc)

3. When both Stevie, Rick and Leven are satisfied with the design,

4. I would like to have Ben model it in Solid and run balance, speed and testing calculations in Cosmos.

5. I would incorporate the feedback from the Cosmos testing into the model and check it with Rick

6. I would like to build a scaled version of it from a K1 kayak hull and do some actual water testing with that version. The only thing in that version that won't be scaled down a bit, is me, but it should be fairly close I would think. We can incorporate feedback from the scaled version to the model.

7. If the scaled version is good enough, I would use it to do some small ocean expeditions to gain experience in ocean conditions and to learn more about living aboard and what I would like to see in the final expedition boat.

8. Then, provide the final design to a professional boat builder and have it built.

EMAIL discussion:

9-22-06 Rick on the test boat and the donor kayaks from Steve at Numbus:


I have looked at proposed possibilities for a test boat(TB1) based

on a body weight guesstimate of 160lb.

The Skana ends up at 313lb (142kg). Will do 9.8kph with 150W at 75%


The NJAK ends up at 263lb (120kg). Will do 10kph with 150W at 75%


I produced an optimum hull with Godzilla for 120kg and minimum beam

of 500mm. It ended up being 6.8m (22.3') long. It would do 11kph

with 150W at 75% efficiency.

This gives you some idea of the compromises. The optimum hull for

150W input would be much narrower than 500mm but I think this is the

practical limit for actually operating in. If you think you could

work in something narrower then I can do numbers on that.

There may be a bit more optimising based on actual ballast required

but the above will allow you to make a choice. Given that the prime

aim of the exercise is to gain experience, I would favour the Skana

as it does not give away a lot of speed and I think the length will

improve ocean operation. If you are really serious about the 24hr

record in the boat then you could think about the optimum hull as

this should do it easily. The Skana might take a bit more effort.

Of course if the hulls are in very different condition then that

would be a factor as well.

9-20-06 I summarized some problems i have been reading about:

After going through a number of ocean crossing web logs, and a least 3 books, I have narrowed down some problems that everyone seems to have, and I would like to make sure we address these either with the design of the boat, or equipment, or proceedures....

1. unwanted backward progress due to head winds. I think the solution here is a good sea anchor and a VERY aerodynamic shape.

2. failure to make forward progress during storms. The solution here could be a water tight pedaling station with secure seat restraints. As I said before, ventallation would be a key issue. I would also want to be able to steer from the sleeping cabin to keep the bow pointed into the on-comming waves.

3. close-calls with ocean freighters and sea trawlers. To my knowledge, nobody has ever actually collided with another boat, but by the number of close-calls I have read about, it is only a matter of time. Typically, a radar detector will ring an alarm if it picks up another ships radar signal. The rower (or pedaler) then makes visual contact with the vessel, tried to make contact via VHF radio, and holds his (or her) breath and crosses fingers.

There must be a better way! I've been wondering about a radar that would plot the traffic and it's vector. Once the vector (direction the traffic is going) is known, I could simply pedal my boat away from the vector in a perpendicular line.

Any other ideas???

4. Desalinator breaking. Seriously - I don't think I have read one single account of an ocean crossing without desalinator nightmares! There must be some logical solution to this problem. Even if it means learning how to build one from scratch and carrying enough parts to completely re-build one on-board

5. Capsizing during violent storms. I think if the boat is designed to capsize - to roll right around, it shouldn't be a problem as long as there were adequate restraints for the occupant either in the drivers seat or sleeping cabin.

Any other problems that you can thing of for the list?


9-19-06 Stevie on the route and time of year:

Canaries to the first island you get to (depending on how far south you are

dragged) in the Windward chain, I would guess. Just pedal your ass off heading due west, and see where you end up, don't waste energy and time correcting your heading for a specific destination. Current is about 0.5 knots. Time of year will be November-December.

Im glad you give the ocean that respect (wanting to get from A to B as quickly and safely as possible), but if a speed record is not important then I'd recommend building something a bit more comfortable. If youre going to spend 40-50,000 dollars and a few years of effort to be out there, I just think it makes sense to think a bit more about what you're going to get out of being there, not just about making it to the other side. Why are you doing it? (I don't need to know the answer to that, but I hope the question is helpful).

9-17-06 Rick with a new optimized hull design predicting 5 knots (over 9 kph) speed!!!!


I have been playing with Godzilla to determine what an optimum hull

would look like for a 1000lb vessel powered by 150W at an overall

efficiency of 80%. The only constraint was that the length should

not be less than 6m and not more than 8m. The optimum ended up

being 8m long. The beam limits were set at .35m to .9m. It ended up

600mm (2ft) beam. You will see the ends have very little buoyancy so

my original hull was not far off. It has a slight rocker which is a

good thing.

The resistance data produced indicates that it should be capable of

5kts with a slight margin for other drag such as keel and rudder.

This is in smooth water so not sure if there is a better shape

allowing for waves.

I have attached a jpg file of the hull and the fbm file that you can

feed into FREEship and extract the hull data for your 3D work if you

wish- up to you. There are a few bumps in the hull and these may be

anomalies or for wave cancellation. I did this to get more assurance

that 5kts will be possible and to look how close the design is to my

original effort.

I also looked at the optimum boat for 230lbs and 150W input. It ends

up 6.8m and should achieve 6.5kts. This would easily set a 24hr

record. I may build a prototype of this boat as it would be good for

my Murray Marathon race. It will also let me see how good Godzilla

actually is. I have been trying to get hold of Godzilla for about a

year so was surprised to see that it is available at no cost.

If you can get hold of a hull we can start to do some performance

predictions as well as test the stability with buoyancy.

I will also remove the 8m limit to see what shape the optimum ends

up. I do not think it is practical to have a width less than 2' but

it will be interesting just to see what the fastest boat would look


9-16-06 Rick on advantages to a ballast keel over outriggers:


Boats that rely solely on form stability for staying upright such as

cats and tris are not allowed in many ocean races because they are

regarded as unsafe. You need a big boat and a lot of seamanship to

feel reasonably safe in a multihull. So give me gravity every day in

rough weather. Gravity is not fickle- it is ever present.

Pilot is a relatively large volume boat and I expect would be

substantially slower than Concept 1. It obviously combines both

form for stability and ballast to ensure it is self righting. The

problem with using form is that the hull will want to follow the

surface so this adds to instability when the surface is irregular.

It is stable in good conditions but more unstable in rough conditions.

The good thing about relying primarily on ballast is that the surface

can roll around but the boat does not try to follow it. More beam

does not mean more stability in rough weather. I think once pilot

got rolling beam on down a wave it would be a bit like a big ball. I

think Concept 1 will be more inclined to get knocked down and skid on

its side down the wave rather than continuing to roll.

A ballasted keel has good and bad aspects. It allows you to improve

stability without adding a lot of weight. It improves tracking and

steering because the boat has more lateral grip in the water.

However it does increase the risk of skidding on its side down the

face of a wave if you get caught beam on.

Without actually comparing Pilot and Concept 1 side-by-side I would

only be speculating which is better from a rollover perspective.

That is why you should test the idea before building a full-scale

boat. The IHPVA site has debated ballast for stability. For calm

water, floats have an advantage. For shallow water, floats have an

advantage. I expect for your scale testing the deep ballast will

work best.

It would be worthwhile doing lines for both Pilot and Concept 1 in

FREEship and compare the hull resistance. The Michlet program also

has Godzilla included. This is a hull optimising program and might

produce some useful results. I would expect that Concept 1 will be

capable of 9kph for the same power input as Pilot doing 7kph . Does

not seem a lot but makes a 50 day trip 14 days longer- not accounting

for assistance or hindrance from waves/current/wind. Do you remember

where we placed speed on the list of priorities? It is a major

safety feature.

My frame of reference is limited to give really good advice. The

numbers will give some idea but there is nothing like experience to

gather knowledge. What I do know is that I hate my OC1 as soon as

the waves get over about a foot high. It would be better if I had a

paddle to help stay upright. I would not recommend a single

outrigger. I can go into the detail if you like. Twin outriggers are

very comfortable in moderate conditions but I have never needed to

see if I could right a boat in deep water. I cannot even use a racing

kayak- I have never had the practice to keep one upright. Canoes are

OK but I have never tried to right one in deep water and then board

it. Catamarans are very secure but they have their limit when beam

on and you could never right one without some form of inflating

device. A 3 tonne yacht with a 1.5 tonne keel is very comfortable

and stable up to gale conditions. The motion is much more severe

without a sail up but you rarely feel unsafe. I have been beam on in

6ft high breakers in the yacht on a river bar and amazed at how the

boat handles these conditions. Only concern was whether water was

deep enough for the 6' draught.

I have attached a photo of the expedition360 boat during righting

tests. The hull is still wider than Concept 1 but looks finer than

Pilot. Concept 1 just takes it closer to the extreme limit of

fineness and therefore speed.


9-15-06 Rick on the outrigger-less design


I had a much more pleasant experience than you. I have just finished

2 hours at the lake in a balmy 20C (say 70F). Did 10km and then sat

in the sun just watching the glassy water and contemplating my boat

steering and your toilet arrangements. I managed a PB sprint speed

today. I got 17.8kph to register. I will look at the track log to

see what the highest averaged reading achieved.

My inspiration with the toilet is to place it below the seat. Tilt

the seat to the side and you have an inbuilt head below. The rim of

the head would be an inch or two above the waterline. You would have

a valve to let water in and there would be a self bailing nozzle

fitted to the bottom. Your seat would seal down and you could air-

blow or pump the chamber to assist the self bailer. The volume of

the head would be very small so filling it with water would not alter

draught much. This is one way until a better comes along. I don't

think you want to take a crap in the living space. Certainly not

using a bucket. Think about being able to crap while still powering

along- what bliss.

Your body weight will be an important consideration in designing the

ballast. I believe you should be able to walk along the deck in good

weather or slide along in bad weather. If it is fitted with high

rails to allow you to walk along in rough weather then I think you

are starting to require the sort of ballast that will impair speed.

Just standing using balance you cannot apply the same overturning

moment that you would if you braced against a rail.

The first three feet at either should be solid foam. This gives

crash protection and adds to solid buoyancy. The boat MUST be able

to stay afloat even if it is completely swamped. If I recall

correctly this is the #1 priority. You will develop an affinity for

the sea but you will not develop gills. It would be good to have a

bilge that runs under floor boards with drains tubes from each cabin

area down into the crank pit. The floor boards would be free

draining to the bilge.

I do not think it is a good idea to store water within any hull

compartments. I have had most success with rubber bladders or

stainless steel. Drinking water held in hull chambers becomes

tainted. The rubber bladders will conform to the shape. They can be

placed through a small hole into a chamber. They can be removed for

flushing if the water goes sour. This is something to ask others

that have done more ocean miles in little boats.

I have also given more thought to the cockpit layout. As noted

above, make the seat above the waterline. Then there is a crank well

that has sides also above the waterline but your feet can fit down

into the pit behind the crank and this will be a very comfortable

seating position when not cranking. The attitude is more upright

than you are used to with a recumbent. This should be a good thing

along the lines of what Dan Grow covered. It also means the crank

can go lower as your heels will not be as prone to drag on the bottom

of the pit.

The crank pit provides a point for standing and stretching. It would

be good if this could be achieved in most weather conditions. It the

cabin top can be raised with flexible see-through spray shields at

the side and front then you have a roomier but still weather tight

cockpit space. You could also place a bench above the crank that

could be used to prepare meals. Maybe a slide out portion that is

set above the knees so you can still crank while making notes,

navigating or a myriad of other tasks. Life will be good if you can

crank at a steady pace while amusing yourself with other duties. This

is a major feature of pedal power over paddle power. Long distance

kayaks use camel back water bladders for water intake but have to

stop to eat. I can keep going while eating and there is no reason

why you cannot do the same.

The more upright seating position will reduce the length from the

back of the seat to the crank. It should be possible to stand in

front of the cranks to gain access to the forward cabin. The back of

the seat could swing to the side to give access to the stern cabin.

You will be able to move throughout the hull in most sea conditions.

If the cockpit is swamped then it can be self bailing for the most

part. You may have to pump out the crank pit so you are not cranking

through water but this will be a small volume.

The deckline will need to be reviewed. I would lower the height of

the deck at the bow and stern but make it higher at the cockpit to

suit the higher seat. Aim to minimise the area of the long section

of the hull while allowing crawl space in the ends of each cabin.

You will be side on as there is not enough width to be flat when

trying to reach the very ends. It probably makes sense to widen the

hull above the waterline to make this more practical.

You should think about cardboard/timber mock ups of these spaces so

you know what is practical.

One last thing- the third-scale boat should also be filled with foam

in the ends. You should be able to recover from it being swamped

while still being strapped in.

There is heaps more that comes to mind but you should concentrate on

getting hold of a kayak to play with.


9-15-06 Level on the concept 1 design

Hi Greg,

The craft looks fantastic! She looks like she is doing

200 mph already! I think Rick has covered most


Another couple of points worthy of mention are;

All the bouyancy of the structure appears to be at the

rear and because of the narow aspect of the bow she

may tend to pitch pole as she surfs off larger waves.

Something to bear in mind perhaps add some fins which

raise the bow out of the water if it submerges to a

certain degree at speed. I would tend to make the

outriggers fixed structures - less to go wrong,

stronger and you wont have to worry about your canopy

getting in the way - the drag will be neglegible .

Only one of them will be in th water any any one time

at any rate out there.

Mechanical and moving parts - especially your out

riggers (I too favour the double out rigger design) -

What contingency do you have and how do they lock in

place? If none make sure they are up to the task and

built simple and very strong - they will take a


If the boat capsizes and you have to get out of the

boat to right it (Rick rightly says to keep the weight

of outriggers down to aid this). Be mindfull of the

volume of water that is likely to get into the hull -

it will not be calm weather if this happens and you

will need a means of getting this water out or

stopping alot of it getting in. it does not take alot

of water to upset weight calculations.

Reduce your capsize risk by keeping the boat pointing

down wind in the same direction of the waves. You

could afford somne legal windage towards the bow to

help keep her pointing down wind whilst asleep or

resting - consider autohelm if you are carrying enough

power - I am convinced for solo row thins device would

not only save distance but if you were able to keep

your boat pointed down wind this would also increase

boat speed during down time. The Woodvale boats

sometimes popped along at 2.5 to 3 knots by pointing

them downwind with their natural windage.

You will need a means to deploy and retreive a sea

anchor from the bow or stern of the boat - in this

design the stern looks more bouyant and therefore it

would probably be best to deploy from there - again,

in my opinion this emphasises the case for making

these structures as failsafe as possible. Calculate

the right size of sea anchor for the weight and

bouyancy of your craft - to small and its not worth

having as it will not bring the craft perpinticular to

the direction of the waves - too large and it may

start dragging you under. Err on the side of large -

but not rediculously so. If you get your sea anchor

deep enough you may even find you are able to MAKE

ground against the wind with it deployed - this

happened to me at Cape Finisterre. Great feeling!

Think about your toilet facilities and the logistics

of sitting on a bucket and getting the stuff out of

the boat without it going everywhere! Cooking is

another thing to consider - force10 gimballed single

burner stove is good and takes standard propane 500g

propane- each gas bottle lasted me a week to ten days.

use a mini pressure cooker - this preserves gas and

saves spillages which can lead to severe burns -

Always protect your whole body whilst cooking - on

four occasions I was swamped by large waves when

cooking - not in terribly rough conditions either it

is potentially dangerous especially with open pans or

pans with lids that come off if upset.

I would also condsider making the floor out of a

honeycombed sectional sandwich. This is probably

stating the obvious again but the canopy should maybe

flip backwards and up with some goretex or canvas

sprayboards at the side -this will give a degree of

protection to you in larger breaking following seas -

again this needs to be very strong if it is your only

means of keeping the water out. The canopy should also

have some form of emergency release incase it jams -

or you build another means of escape.

Your EPIRB should be of the GPS variety so you can be pinpointed in the worst case scenario. Batteries in EPRIB's only last for 48 hours max - I would put 20, not 2 flares into your grab bag (the military have very good lightweight miniflares) and a mini hand pumped watermaker may weigh less that emergency water. Stay attached to your boat at all times especially in heavy weather. Have the means to stay attached to your boat even during an escape scenario. It wouldn't hurt to have a few rope handgrips on the outside of the hull - you may need to get out and clean of razor barnicles in the last week or so. Antifouling, regrettfully, does not seem to keep these little critters off terribly effectively unless you have stronger stuff state side.

I hope this helps.

Best wishes


9-13-06 Rick on the test boat

The attached sketch shows what has to be achieved with a Kayak to

make it self-righting. The sections are almost round and it will be

designed to float with the rounded sections just submerged.

To get self-righting the CoG needs to be below the roll centre. The

roll axis for a round section is the centre of the circle. If the

hull has flatter sections then the CoG can be above the waterline and

it is still stable. This is the situation if the hull is on its side

but the analysis is not as obvious as a circle.

Overall you are probably better playing with a ballasted kayak than a

canoe. It would be a faster boat as well. You should be able to

cruise at around 7mph with your power level so you could use it to

set 12hr and 24hr records along the way.

The CoG with you in a pedalling posture will be say 4" above the roll

centre (waterline in this case). We assume the total weight is

220lbs so the unstable moment is 880inch pounds. If we use a ballast

of 22 pound it must be set 40" below the waterline to get stability.

It could be mounted off the bottom of drive leg to reduce the amount

of appendage drag.

This sort of stabilising keel requires relatively deep water for

operation hence it is not suited to normal kayak usage. Normally a

paddle is used to stabilise a kayak. Outrigger canoes are even

narrower than kayaks. So narrow that the paddler cannot sit into the

hull hence the need for the outrigger. They could be stabilised with

a keel but it would be a greater penalty than the outrigger and not

practical for use in the surf.

I think the ballasted kayak is the best option for testing as it will

be a fast boat and you can easily play with the ballast to optimise

fore/aft trim as well adjusting the righting moment. The only

penalty is the minimum depth of water you can operate in with the

keel fully deployed.

You should draw up the ballasted kayak and look at the proportions.

9-13-06 hard chine vs a rounded one, kayak for the test boat vs a canoe, tipping

I wanted to give you an idea of the penalty in going to a hard chine

compared with rounded sections. The increase in wetted surface is

12%. This will equate to a speed difference of almost 6% for the

same power input. In a 50 day crossing without current assist it

would mean a difference of three days.

The general consensus is that a hard chine will assist with roll

dampening. This is something you would need to experience to asses

the merit. I think there are other ways of improving the sea keeping

qualities without suffering the full 12% penalty.

The other aspect you should be aware of is that I am a fan of

straight rocker. You will get divided opinion on this. I have one

authoritative analysis which proves it is good for speed and it is

standard design for rowing shells. However the latter are intended

for calm water usage and others would argue that the ocean is a

different matter. I feel you have enough buoyancy in the ends to

avoid pitchpoling without the need for some rocker to give lift when

running down waves.

Some detail on the actual hull - If you consider the plan view as

three sections made up of foreward triangle, middle rectangle and an

aft triangle then I expect there to be an advantage in making the

forward triangle say 11ft, the middle 5ft and the stern 8ft. Thus

making the bow taper finer than the stern taper. There is some

scientific background to this but I have not verified it

conclusively. It should reduce wave making at the top end of your

cruising speed. If you look at the plan view of a K1 you will see

similar asymmetry between the fore and aft plan view.

Another bit of detail concerns the deck. If you need to walk/crawl

on it to get to hatches then it will need some rails.

I have reviewed my thoughts on the canoe versus the kayak for a test

boat. To get an idea of stabilisation using gravity you need a hull

that will sink down in the water when loaded normally. The kayak

will be better for this than a canoe. It will need to be ballasted

to achieve a positive righting moment and this would be best done

with a keel with say 20lb and 4ft down. The keel could be lifted for

approaching the shore as is done with a sailing dinghy. There is a

problem of scale with the smaller boat because the body height is

fixed so the test boat will be rather slab sided.

To look at self-righting we should start calculating the righting

moment so you know what works and what is too twitchy. There is a

risk that the test boat you build will be more stable in its side

than right way up. This could also be the case with Concept 1

without doing some numbers. Ideally the CoG should be below the


Concept 1 will become twitchy when unloaded so this aspect needs to

be considered. With rounded sections it is suitable for more than

1000lb. displacement. There may be a case for narrower waterline.

9-13-06 Ricks comments regarding a test boat made from a kayak


I think it essential that you gain sea experience. You should aim to

build good relationships with local authorities, recreational boaters

and fishing boats. All can be sources of ideas and accelerate your

learning curve.

You could probably get hold of a two person Canadian canoe that would

be closer to Concept 1 than a kayak. Here are some examples:

The longer ones are generally wider than ideal. You should be looking

for a hull 24" to 30" wide and around 16' long. I an certain the K1

kayak will be too tippy to give you a realistic feel. It would be

impossible to operate without outriggers and then it is no longer

self-right. Adding a higher deck will lift the CoG. Also you will

not have the reserve buoyancy to carry any provisions. The Canadian

canoe will not be an outright speed machine but it should be OK for

traveling long distance at respectable speeds.

I think you should be designing for 150W based on the power readings

provided. This may give slightly higher speed numbers than I have

given but my numbers are for smooth water and waves will help or

hinder. On flat water is it very steady effort unless there is

wind. What cadence do you like at 150W output.

Another thing you could do is build a timber and cardboard mock up of

the Concept 1 hull to give you an idea of how cramped it will be.

It will help with placing things you need to get at and laying out


The drive leg for your test boat could be made very similar to that

for the larger boat. The engine is the same. The resistance may

also be very similar as the canoe will make noticeable waves around

5mph. You should see if MicroMatine are still working. I can

provide suggestions on gearboxes that would allow you to quickly make

a drive leg if you need to. Components are not stainless though so

corrosion would eventually become a problem. You should try to get a

gear drive having 4X cadence as this gives close to an optimum prop.

You could nominate a displacement based on what others have done.

The boat is close to the minimum size to actually operate in and

should be able to displace up to 1000lbs with some efficiency. This

should be ample to get by with. I think you have to decide on the

position of the drive leg and seat rather than having adjustment.

The trim can be set by where you place gear. I would aim to have the

middle of my bum just behind the middle of the boat. So the leg is

about 2' or so in front of this. A few pounds shifted from bow to

stern would correct the trim. If you want to keep most of the

provisions in the bow then maybe have the seat further back.

Remember you will probably want to use the boat lightly loaded as

well so you cannot always rely on provisions being in the one place.



Ricks feedback to the Concept 1 design:


Your drawings are outstanding. I would be surprised if the images

will not be attractive to potential sponsors. I will look forward to

a post on the IHPVA site. It will give people that lurk there a

lift. Some comments:

1. The sections are flatter than I intended but this could be a good

thing. It will give you some form stability that will help staying

upright. The hard chine also dampens rolling motion. There is a

penalty in wetted surface though. You need to do a calculation on

the wetted surface for the intended load. The actual weight should

reduce as you consume provisions so it would be worthwhile doing full

provision and light provision waterlines.

2. I do not think the sleeping position A is practical. You may

find that you will need to have the seat further back when fully

provisioned to get the trim. This boat will be very sensitive to

weight distribution. You should always aim to be able to achieve a

slight bow-up trim. By the time you get the seat in the right place

I doubt that you will be able to get enough width for your feet.

Position B is probably more practical. You may be able to keep the

sleeping chamber separate by actually having a combination of A and B

with your head below a sloping bulkhead behind the seat in its normal


3. I like your idea with the three chambers. However you should

design the boat to have enough solid buoyancy (in the skin and ends)

to keep you and the contents afloat. This should not take a lot of

solid buoyancy such as expanded foam as the SG of you and most

provisions is less than 1. Ideally you should be able to recover if

all three chambers are flooded.

4. I think it would be desirable to be able to open the cockpit

hatch while the outriggers were stowed. There should be many

opportunities to open up and keep moving at top speed.

5. I prefer the 2 outriggers to one. In the end you may find it is

better to operate with them deployed in all-but survival conditions

when there is high risk of capsize. I expect that the boat would be

quite stable with outriggers that displace around 40kg. If you can

keep the outrigger displacement around half your bodyweight then it

should be possible to right the boat with them deployed by standing

on one of the outriggers and foring it below the surface. A single

outrigger usually makes the boat easier to right but it is no where

near as secure from a stability perspective. In fact it is more

likely to promote a capsize.

6. I envisioned the foredeck having more slope to reduce frontal

area but the fine entry should be OK. It will also give you some

lift if you are riding waves.

7. I expect a rudder about 12 inches deep and 4 inches long mounted

about 2 feet from the stern will do the job. Run steering cords in

tubes along the inside of the hull within the sleeping chamber. The

boat should track well anyhow. I find a steering arm mounted below/

behind the seat to be most relaxing.

8. Your drive leg is bigger than I think is possible. You should be

able to keep it less than 3/4" thick and about 5" long. The prop

tips only need to be swinging an inch or two below the hull. The

prop can be pushing or pulling. If the leg is fat then you get

vibration from a pushing prop. There is a very slight improvement in

efficiency if the prop pulls as it does not work in the wake of the

leg. It is slightly more prone to damage from striking something if

it is pushing. I think a two bladed prop will make it easier to lift

the leg for inspection than a three bladed prop. Also the two bladed

prop reduces draught for boarding from the beach.

9. The storage space in the ends is very small as the hull is very

narrow. Probably better just to fill with foam to give collision


10. You should be thinking about a low spot in the hull to catch

runoff. This is probably best around the drive leg. It needs to be

deep enough to pump down so the water does not slosh around the rest

of the hull. I have only ever seen a dry bilge once in my entire

life and it was in a land locked power barge that had huge diesel

engines generating high temperatures. Always too hot to get


Look forward to getting into more detail. Remember you should be

thinking about a specification. Useful design stuff is to know what

power you hope to be able to sustain from your engine.



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.

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