solar splash

[quangha1944]

hi everybody!!
we are mechanical students at Cal Poly Pomona California. We currently building a Solar Boat for June 2003 competition in New York. OUr idea is to go for tunnel hull design.. But we need more supports and technical information such as formulas and calculation how to build it...Please helps.. the boat is limited 4.5'x19'. No weight limit. Thanks

[Willallison]

What kind of speeds do you hope to achieve? That will determine the best hullform for the purpose.

[Stephen Ditmore]

Check out these links:

http://boatdesign.net/forums/showthr...p?threadid=208

http://boatdesign.net/forums/showthr...p?threadid=797

Electric Boat Design

http://powermultihulls.com/magazine/...at%20hulls.htm

Multihull Resistance

Thanks for replying.!!
The max speed in the competition last year was 32 mph. That is for the sprint run which is only 300 meter. There are sprint , endurance, and slalom run. The endurance is needed to run for 2 hours long with the solar panels on , the avg. speed is 6 to 8 mph(most points credit).this year we want to achieve at least 35 mph for the sprint and 8 to 10 mph for the endurance. There are 3 types of hull we are looking at right now: the planing, the classical Cat ( with 2 narrow hulls) and the tunnel hull. We test the Cat vs the planing hull, and the planing does good in high speed but not in low, the Cat is the other way around. Now we think if the tunnel will do both or not... We need more advices and supports. Thanks a lot

[tspeer]

I'd consider a trimaran - basically a very long monohull with training wheels. The ama's (outrigger hulls) would need to have planing shapes. In essence it'd be your two cat hulls end to end for the greatest possible length with very low wetted area. Since you're electric powered, you only need a minimum amount of lateral stability.

The amas can be mounted so they don't both touch the water at the same time, cutting wetted area. At speed, the boat will probably sink down a bit, so mounting the amas at the stern will bring them into play at high speed.

[jonathan]

The only problem that I can see with your idea, tspeer, is that their length is limited to 19', so that a very slender hull might have to be fairly deep, increasing wetted area.
It depends of the expected displacement.
As for tunnel hulls, sorry but I don't know much about them... :-(

[Stephen Ditmore]

Could I find out more about the competition? I live in New York and would love to attend.

Do you have to use the same boat for the sprint and the endurance? Is there any way you could move weight aft for the sprint and forward for the endurance?

What are you using for your propeller?

If you wanna find out more about it pls. go to http://www.solarsplash.com/

[tspeer]

Originally posted by jonathan
The only problem that I can see with your idea, tspeer, is that their length is limited to 19'...

Ah. In that case, you're stuck! Hydrofoils may be the only recourse - they can be deployed for the speed event and retracted for the endurance event.

It might be possible to use an unstable to marginally stable single hull with rounded bottom for minimum wetted area, and let the pilot stabilize the boat like a kayak with only occaisonal touches with a "paddle" specially designed for the purpose. If the boat had a high center of gravity (to lower the natural frequency) it might also be stabilized with an automatic control system to the steering or to a small fin - a bit like the classic inverted pendulum problem. Big problem with a standing start, though!

[Willallison]

How about a splitting hull. The two could be 'clipped' together, end on end to maximise length for the endurance run. Then put side by side to form a shorter, wider platform for the planing run.
Haven't given hullshape much thought as this is just an idea that popped into my head.....

[yipster]

32mph on solar power with a fire fire extinguisher and what else onboard???!!! wooooow!

if a retractable hydrofoil is not within the long list of rules maybe its worth considering a -fast- torpedo type swath design? i have not seen that yet and its only a thought. for speed and endurance i like to think it might do, slalom not.

how much power do those solar cells give? other solar power use allowed?
rule "7.4 Power - Sunlight is the only power source that shall be used for propulsion. Wind and human power are not allowed. The sunlight may be direct (received onboard during the Event using energy conversion devices) or may be stored in batteries or in other approved energy storage devices." ???

13. Prizes and Awards: The Sponsor and Organizer of the Event will recognize all Teams' participation. In addition, the following awards will be presented: 13.1 Daily Award - Some awards will be presented at the Skippers' meeting and some on Wednesday evening. 13.2 Overall and Runner-Up Awards - For each competition, an award will be presented to the Team that demonstrates the best performance. Runner-up awards may also be presented. An Overall Winner will be determined by a formula which includes: Technical Report, Visual Presentation, Workmanship, Qualifying, Solar Slalom, Endurance, and Sprint. Runner-up awards may also be presented. !!!

what or how much? many rules and no prices? you can only show 3 sponsors on the boat? and we cant even come to compete!!!

maybe you want to talk to the dutch guys that won the cross australian solar powered (at 60?km) car race? that and more in a solar boat in new york is not gonna be easy! keep us informed!

i'm dreaming, try a "hyswath" but reserve time to learn to drive it! and maybe the big trick is to get the best solar cell's???

they allow you to store the energy in the batteries when you do the sprint run. Check out the last year results to see how fast it was.

[Stephen Ditmore]

I have a variable geometry proposal that's a variation on things mentioned by others. How 'bout a trimaran with a 19' displacement center hull and (~10') planing floats that just kiss the water and are not unlike jet skis. For the sprint remove the center hull and it becomes a (~10') planing catamaran!

[yipster]

sounds like the best one so far to me!

lots of unproved versions but one that i have used and proved to need at least 20% less power to produce same speed as conventional hulls is the IVB!!!!
don