Coastal Cruiser

Will

You make a fundamental error in your assumption. As I have pointed out numerous times on numerous threads I do this as a hobby. My real work pays very well by most standards and my investments do well even GFCs considered.

I get many requests to build pedal boats for people and also offers for paid design work or for an opinion on a particular design. To be paid for the work associated with this hobby would be in conflict with my real work and creates an issue for professional liability, which would also jeapardise my real employment. I do not have any mechanism for receiving payments. Any design I do is for free and there is no obligation either way. If I do work that goes beyond a concept, any further costs are paid directly to whoever provided parts, materials or labour.

I am not pushing any barrow here. I responded to someone who revived the thread and I pointed out what had evolved from my original idea.

I am interested in making a solar boat but my first foray will be a day boat around 10m length to play with and do real world on-water testing on solar panels. It will be based on the stabilised monohull form and something I can build in my garage. Budget will be about AUD10k.

You may have to tout for work in boat design but I don't. So your fundamental assumption is wrong. I get the impression you do not have much better to do than try to shoot down ideas that might challenge your concept of a "real" boat.

As matter of interest I went to the lake yesterday and the number of human powered craft has doubled since a year ago. That is where the growth is in the boating market.

Rick

 

Rick

This is the outcome of your hobby, ingenuity, persistence, multi-disciplined approach, your focused interest, and your generosity in sharing your thoughts with others. I have been following the conversations, thoughts, and interest from forum members and have been fascinated and intrigued by the information presented in this thread. I have also been impressed with your patience and willingness to impart what you have learned through the continuous development of the concept. I believe your projects will have an impact on 'boating into the future'. I'm glad to read that you have seen an increase of "human powered craft" when you went to the lake yesterday.

Thank you Rick.

Keenly interested.
Harry Tams

 

Thanks Harry.

It would be good if I could devote full time to the hobby but I am still working for a living.

The pedal boats also get in the way of doing other interesting things with boats. I believe I have got to a reasonable level of development with these and there are quite a few copying but I tend to do specific designs for them so it absorbs time.

I get quite a few requests for input over a wide range of topics and a few things get built so they all expand my learning horizon.

Rick W

 

Ok - my apologies Rick. I got the wrong impression when you stated...

 

Ok - so for arguments sake, lets say you could produce this boat at a displacement of 2500kg. What would that do to your power requirements, in terms of supplying them with solar / wind? Is it still a viable proposition (in terms of practicallity, I mean. As you've already agreed, it doesn't currently make sense in purely financial terms at any displacement)

 

The power demand is slightly more than twice if the length remains at 13m. Adding extra length to say 16m is beneficial. 2500kg on 16m would need 70% more power at 10kts than the 1000kg at 13m.

A 2500kg boat 13m long requires 4.16kW to do 10kts or 2.19kW to do 8kts.

You would want double the weight of batteries and double the weight of solar panels. There would not be enough space to mount 10 x 210W panels on a 13m long boat.

You start to see why there is considerable value in spending the money on expensive materials to keep the weight down.

Rick W

 

This little u-tube skit was sent to me by a fishing friend. Maybe helps explain why the growth is exploding in the smaller areas up to canoe size and including HPB.

http://www.youtube.com/...amp;et=1264554218.44

P

 

Vic
I get a message that that page cannot be shown when I follow the link.
Rick

 

Yes - I'm aware of most of that... but what I wanted to know was whether it would still be viable in the practical sense. From what you are saying about the required panel area, it wouldn't. So this is (at current prices anyway) never going to be a boat for the many, let alone the masses.
Adding length in a displacement craft is always beneficial - so long as you don't add weight as well.... the age old conundrum......
I still don't believe it can be done practically at 1000kg - or thereabouts - but it would be an interesting exercise to look at the cost / power / size variables to see whether a practical position could be found. For example, the cost of building 1500kg might be twice that of building 2000kg, but the subsequent area required might make 1500kg the only viable option from a powering perspective....

 

OOPS, 2nd Try: http://www.youtube.com/watch?v=FYor9P3zAUc&feature=sdig&et=1264554218.44

 

Your guys are making me worried now.

Here my last and youngest daughter has been pushed through University and studies. Now after 7 years (double degree, Honours etc. ) at last some money is coming free. I order a solid design from NZ, after 5 weeks still nothing in the post. Born in Rotterdam, having seen hunderds of electric boats on the channels and ijselmeer, from small 3 feeters to 10 meter (hybrids), I decide to start making my electric boat. Start doing some crazy concepts to feel my way in what is possible and what not. Solar panel reflectors, solar panels in serial, pipe battery, super capacitors. The only person who I am learning from is Rick, who is the only person who shows in flying colours, not even in black and white, that things can be done a certain way, he get shot down !!

Let me give you a chance to shoot me down also

This will be my concept.

1) A 18 feet design from a well established designer, which can be lenghtened to 20 feet
2) Monohull, heavy unfortunately, except if I use very light wood.
3) Solar panels, which can be folded open.
4) Reflectors to squeeze the last drop of photons out of the sun.
5) Solar panels switched in serial to squeeze even the absolute last drop of
milliamperes to charge the batteries.
6) Voltage doublers
7) Unless the price comes down for Lithium, I will stick to SLAB's or NiMH and make provision for future technology improvements. This will take a very long time, as the motorcar industry and oil companies will delay that process as long as they can.
8) Not racing over the water, but at a reasonable pleasant speed.
9) Also, like Rick , 5 Kw electric motors, with 16 Kw peak for 10 minutes each.
10) Turbine? or propellor wind charger?

Please Rick, carry on, I can only learn from you. And for all the professional architects, please could you ask your colleague in NZ to post me the paid for design. At least I can then start building. ( I don't get response to my e-mails)
Bert

 

Hi Porta, that was hilarious, but very much true.

 

I could prove you wrong on the 1000kg or thereabouts if I took the time but as you have no serious interest in the concept there is no point.

What most do is to scale in three dimensions. My V14 hull weighs 10kg and is 6m long. The 8m red hull weighs 54kg. Both are robust construction. A feature of low weight to strength is that there is not much momentum at the speeds being considered. The V14 hull has been dropped, beached and run over logs. It is hard to damage something that reaches terminal velocity in a few feet. I selectively strengthen areas like chines and ends to take a bump. It is an enclosed box so inherent strength. It is stiffer and stronger than an open hull like a kayak.

You are still thinking in terms of a hull that has to carry a lot of power with concentrated loads and forces. This is not the case. Even batteries can be distributed to spread load. The loads on the turbine are miniscule compared with a sail acting on the same area, which is not very big anyhow. There is no mast, chainplates or keel creating concentrated loads.

The hulls on cats can be built light but the interconnecting beams create stress concentrations. There are no stress concentrations like that in the hull. The hull bottom does not have large unsupported areas like you have with a planing hull without internal stiffeners. The moderate speed and acute entry angles help reduce slamming loads.

It needs to be designed from scratch working from actual loads rather than applying rules-of-thumb based on current experience.

There can be some sacrifice between performance and cost but using inexpensive materials will rapidly degrade performance.

Rick W

 

engineering lessons

You keep using the phrase "not constrained" like that and it keeps confusing me. Obviously there is a constraint on how long the length can be...

This must be a term of art that I'm not familiar with. Can you explain what you mean?