Pedal Boat Design

Thats how I am gonna do my top. The Yellow one, not the teal lol.

After reading Greg's blog and his findings on how little the wind effects the boat with and w/o a fairing...why not add a top. South Texas son is BRUTAL.

Greg--

My day was loaded up by 7 this morning. I will get that email off to you as soon as I see a little daylight.

 

Sun protection is a consideration. I have a foreign legion cap and full length snow white Skins for long days. I look a true picture. With skins and fresh water you can actually get cold on a hot day.

http://www.skins.net/au/en/Products/BioAcceleration_Technology/sport

Rick

 

Wow...those seem pretty cool. And UV 50 protection certainly can't hurt. As soon as I shave off about 20-25 pounds I will have to get some.

As for hats, here it's the straw sombrero =)

 

The thing with the Foriegn Legion style cap is the ability to just dip in the water and moisten the back flap. The evaporative cooling is quite effective.

The one race I have competed in a couple of times covers 404km and I have experienced temperature to 48C so cooling is a must.

Rick

 

Yeah, we actually use a very similar item. It's a cotton cloth flap like piece that goes down to just bellow the shoulders that is sewn onto a stretchy material skull cap. It's like that biometric concept in the Skins you linked too as it squeezes the head increasing blood flow to the brain...



As for dipping the thing in water for some "swamp cooler" evaporative cooling action...dipping it in water would actually make it drier... swamp coolers are not much good in 80% humidity lol.

How to tell your in South Texas:

Everyone owns at least one gun.
The deer are the size of poodles.
Barbecue is fine dining.
Winter Texans from Canada suffer heat stroke in January.
Bread is spelled "Tortilla"
Car is spelled "Truck". So is Sport Utility Vehicle.
You learn why the humidity can be 100 without it raining.
You have no idea what a hill looks like.
Trees only come in two varieties. Palm and Mesquite.
You mow grass once a week 11 months out of the year.
Wearing a foreign legion hat or Skin suit is an excellent way to insure a beating.
The exception to the above is "ol' One Nut" who gets a pass because he has been to France.

The good news is I think I have FINALLY sussed out my down struts WOOT!

 

In Australia we have oil/gas and water close to par on price - at least it seems that way. You cannot wash your car unless it is with recycled water. You cannot water the garden unless the water has been already used for things such as washing - so called grey water. In Brisbane they are drinking their recycled sewerage water. Rinsing dishes before putting them in the washer is frowned on. A 4-minute shower is regarded as excessive. You do not flush for a #1.

We would just love to have more water here.

This link shows our largest water storage:
http://conservewater.melbournewater.com.au/content/thomson.asp

Just before my first visit to Texas I was told don't touch their beer or women for obvious reason you have stated.

On one visit to the US some years ago I was in a small town in Utah standing at a road crossing and this odd looking vehicle pulled up. It was narrower, higher and shorter than everything else around it. It got my interest so took a closer look and was staggered to see it was a LWB Toyota Landcruiser. In Australia that is a big vehicle. In Utah it was oddly awkward and tiny.

Just this year I was in Montana and learnt the lesson that two Hummers require 3 parking spaces. If you park between them you cannot open the doors. In Australia they would need 4 spaces - imagine Paris or Milan!!!

I forecast North American cars will get smaller or just disappear. Our two large carmakers are struggling for volume of the Australian produced large cars.

Now I'm right off topic.

Rick

 

Plank's constant vs. Rick constant

Hi everybody
you may not remember the exact value of Plank's constant, but we all are certainly familiar with Rick's constant of 40% more power required by catamarans than monohulls.
Rick is a fine PPB builder and an inventor, and he doesn't miss the engineering point that choosing and architecture means to address a trade-off between different goals, and comparison ar well done if all the specifications are stated.
Rick's constant is correct (if a bit crude) for boats of the same displacement boats without any other constraints. If length is a constraint (it is if you need to transport the boat on a car, for example), the cat architecture can be the better choice (it depends on the other specs) as Rick himself noticed.
Other issues can be user friendliness, stability, maneuverability et. al.
Comfort, too, can be an issue. Monohull require lower seat level, and this can lead to less-comfortable and inefficient positions.
So, Rick's constant is not a constant after all; the issue is more complex and for a start we need a set of specifications.
We are trying to do just that within the Open Waterbike Project here:
http://www.openwaterbike.com/architecture/the-open-waterbike-requirements. We believ these specifications are just common sense for recreational high performance PPBs.
Please give us your opinion.
Best regards
Beppe
Founder, The Open Waterbike Project

 

I think that when comparing boats efficiency the 40% more power required for a cat than a monohulls is not the best measure to use, as you don’t set out on a pedal powered boat to achieve a certain speed. You set out with a specific power available (depending on how fit you are) and the speed is a product of that power available.

Therefore a better way to present an optimization is to say that for a specific power say 150w a monohull can achieve x% higher speed. That x% will be nowhere near as impressive a number as 40%. Rick do you have the Drag versus speed charts of the optimized monohull and catamaran so that your optimized hulls can be presented in that way.

Personally I believe a boats usability is related to its stability and in that context a cat may be more efficient than a monohull for a given stability when the stability requirement gets higher.

BG_Geno thanks for the oven information what part of South Texas are you from, I get out to San Antonio a couple of times a year.

Gareth

 

Beppe
I do not lay claim to the "constant" it is a matter of physics. A function of viscous hull drag in water and gravity wave production from the hull in deep water.

To restate for clarity - a catamaran will require 40% more power to achieve the same speed as a monohull of equal displacement when both are optimised for the same cruising speed at normal level of human power.

There is no accident that we see the exclusivity of monohulls in Olympic rowing, kayaking and canoeing. The hull types evolved for their performance, arguably a little hamstrung by certain rules of uniformity. Not a catamaran amongst this clutch of high performance boats.

My choice is to have the ability to cover the water easier than walking at 10kph for less than 100W rather than do a five minute burst of 250W to achieve the same speed. The latter is your choice. I am not bothered that your choice is different to mine. I do not see any need to agree on it. I am certainly not interested in wasting effort for others' perceptions of comfort or convenience so I can get standardised parts for slow boats. I enjoy being able to outpace sailing boats and other human powered craft. I enjoy having a boat I can pick up in one hand and easily place on the roof of my car without it being disassembled. I am not driven by the need for consensus as you are to satisfy your research project.

Rick W.

 

Open Waterbike and common sense

Please, Rick, do not refer to me intentions that are not mine. We are not interested in building slow boats, but we are not interested in building unsafe or unconfortable boats either. Modularization and standardization are different issues. Please don't talk nonsense. I highly respect you and your achievements and your ideas and I believe the Open Waterbike Project deserves the same respect form you. And I believe that the same respect is due to any colleague. I believe the concept of specifications is an engineering concept we can discuss it together without abusing each other. Please let's keep the discussion of a technical and scientific level.
The Open Waterbike Project has just started and we will see in the long run where it is headed and if it will lead to better boats or not. But a success of the project would also contribute to the succes of the ideals of human powered pedal boats.
Beppe

 

Gareth
You can read my previous post on the relative power of two examples of PPBs.

My design process is to design for the best speed I can get with my continuous power output which is around 130W depending on my level of fitness. I am hopeful of pushing this up a little so I design for 150W - ever hopeful. My objective is to go as fast as I can with this level of power. Through iteration I found 12kph was about the limit using 150W for a practical boat carrying my weight and using the best propulsion efficiency I can achieve. So 12kph is my design speed.

The boat is not inefficient at other speeds but it is the minimum drag hull for that speed. There are other losses such as windage, prop shaft, prop propulsion inefficiency, rudders, stabilisers and mechanical efficiency. The end result is that I can achieve 11kph at my continuous output or doddle along at 10kph for a tad over 90W.

If you are prepared to tolerate the inefficiencies characterised by Beppe's Open Waterbike then you must be prepared to do 7kph at a lazy 90W or push up to 220W to get up to 10kph. The 12kph that requires 150W on my V11 series boat requires 344W on Beppe's Open Waterbike.

Regarding the main point of your post, with an optimum catamaran you should be aiming for only a 10% speed difference to an optimum mono for any particular power level. This may not seem much but look at the difference between Olympic gold and 4th place in any event. In this analogy 10% would be a century ago.

My aim was to design the best boat I could based on safety, speed, usability and just being fun. Price was a factor but then I could be paying fees at the local golf club and getting a fraction of the fun. Part of the fun is burning off the Saturday afternoon sailing fleet. I was once invited to race but it was more than a little embarrassing for the sailors in light airs. Even in strong winds I can outpace a 14ft cat over a triangular course. The cat goes faster over the water most of the time but I go where I want not where the wind dictates.

Just to be clear on terminology my stabilised monohull is actually a trimaran where the outriggers normally sit just above the water level. It is as stable as a catamaran where you are sitting higher to get clearance over the water. I also find it an easier motion without the snap roll you get beam on in a cat. I can just shift body weight to balance in anticipation of the approaching waves. In the limit the outriggers have huge leverage to prevent capsize.

Rick

 

let's nip this right in the bud =)

One thing with Rick that some of you miss is that he is an engineer. Engineers deal in quantifiable absolutes first and foremost. Most of the rest of us are not engineers and as such are tinkering and day dreaming about our own personal idea of what ideal is.

I imagine it is rather hard for Rick to communicate with a lot of the tinkerers in here. I am sure it is difficult to communicate with me. Yet he is here day after day answering our questions and helping where he can. If you don't like him pointing out the hard science of your design choices then better not to ask. When you look at what he is communicating beyond the math his real meaning is obvious.

If you want a cat for w/e reason that is great. Just be aware of the limitations of the design now before you spend tons of money and time. Don't expect your cat to cruise at 12kph like a well thought out mono. Don't think trundling it to and from the water will be as easy etc. The vast majority of the times when people are unhappy it is because of unrealistic expectations. I would prefer he point out the mistakes in my expectations now then learn them this spring when my boat isn't what i expected while I toiled on it all winter. He isn't just handing out the math folks. It's called wisdom.

As for your open water bike project Beppe. I agree in principle that some types of standards can be a good thing. The problem is not in setting standards but rather in who picks them. Design by committee never works IMHO. Standards that help communication and quantification are worthwhile but much beyond that and you stifle free thinking. I have followed your postings in other threads and there is a pattern. Topics and ideas will be flowing along nicely. Then you appear with a standards committee and the conversation becomes about the committee and bickering follows. In my mind that is proof that DBC is evil lol.

You asked for my opinion, here it is. In stead of discussing the best way to advance HPB's, PPB's, or whatever you want to call them, lets just build better boats and let the sheep do what they always do. Follow and complain in equal measure.

Or we could just schedule a meeting to figure out a way to have more productive meetings.

 

Here is some...call it perspective.

The proof is in the pudding as they say. Rick's a fairly modest bloke so I will dish out the pudding for him. He has designed what is likely the worlds fastest pedal powered displacement boat. Not just for sprints either as the world record attempt for most distance in 24 hours will be made in HIS design. The boat is not some fragile little craft built in some state of the art facility either. It was built in a garage and is the actual boat Greg trains in day after day week after week.

A cat works better for me and I just find them sexy, and thanks to his help I intend to build the worlds BEST cat for Geno.

When the OBP puts out a merit worthy design we can talk. A great SELLING boat doesn't count for the record.

 

Open Waterbike and collaboration

Rick
this comparison you make here is unfair:
1. The Open Waterbike is a project, not yet a boat right now. My catamaran is only the staritng point, a prototype 0 useful to discuss modularity and specifications and to show the potential of the PPB concept with photos and videos;
2. The data you give are from my boat of ten years ago (when, I believe, you weren't yet building PPBs) and were characterized by and unusually low propelling efficiency,as we noted in the paper. I gave them to you to discuss them , because they are hard data carefully measured, including the metabolic power that I believe you never measured directly, and I would like to work on them together to align them with your data;
3. The same boat, better tuned with an higher efficiency, won the World Championship back in 1999, the second boat arrived 10 minutes later, distanced by more than a kilometer, and a few production boats (Seacycles and Surfbikes) arrived even later;
4. We have now a better prototype, not yet measured, and probably much better, but we are not interested in boasting it, but in using it as a start-up of the collective innovation project.

All this il clearly stated and shown at http://www.openwaterbike.com/.

5. It is unfair to compare a 7.2m long boat with a 4.80m long one. We said that before. Can you break your hull in two for transportation on a car? We chose the length for transportation on a small European car. We disassemble it and each piece is less than 10 Kg, than assembe it in ten minutes, that could be even better for some people than a single heavier boat.

I believe we should align the data we have and use them to understand the potential of PPBs. I gave those data because they have also the metabolic power measurement and this gives us a better chance to understand; you used them to ridicule the project and this in not nice nor fair, Rick.

Finally, I can't really understand your hostility; we are up to the same goal, and we are open to collaboration according with the goals stated by your introducing your thread; please let me know if there is a reasonfor this unexpected bad attitude of yours towards the Open Waterbike project.

Beppe

 

Beppe
This is BGs thread for his boat design. I suggest you take the question back to the PPB thread so we avoid cluttering this one with unrelated issues. The thread I started was for more general topics such as this. Alternative would be to start your own OPPB thread.

Beppe I should add that I do have a warped sense of humour similar to many Australians and I do enjoy TTPOOP when the opportunity presents. My humour sometimes goes awry. My intention is not to offend personally although I will challenge your beliefs.

Rick W.