Building Solar-powered Inland Cruiser

Aloha from Hawaii,

I am currently contemplating building a composite, unique, advanced solar (photovoltaic and wind generator) powered vessel for cruising the inland and protected waterways of Europe. The approximate specifications are 50 feet long, 18 feet wide, twin hull, possibly SWATH and covered by a roof holding about 8000 watts of photovoltaic cells and 2000 watts of small wind turbines. Battery storage of 8000-12,000 watts and a backup bio-diesel generator. I want to design the most efficient, robust, and low maintenance system possible. The vessel will be used for living quarters and slow cruising of the protected and inland waterways of Europe. I expect a speed of around 6-7 miles per hour driven by two electric outboards of 5 hp each which could be mounted fore and aft with 180 degree rotational ability for a high degree of maneuverability in tight spaces. The hulls must be the most efficient possible design and be extremely rugged and lightweight with perhaps sacrificial elements. I have a sketch of the boat I have envisioned, but I can't figure out how the insert function works on the posting page. When I click on the insert image icon a box requests a URL. Can anyone explain?

Anyway, the goal is to create a new form of on-the-water habitat using the most environmentally benign technology while providing an aquatic living opportunity of ultimate practicality and comfort. I have spent much time on the water and am an expert in photovoltaic systems.

Is this a project any of you would be interested in? If so I would like to hear from you with any comments about the approaches you might think would get to the goal.

Hope to hear from you.

 

sounds interesting, try to show your thoughts again.
when uploading from your harddrive you have to scroll down in the reply screen to the "Additional Options" field

 

Solar cruiser pics

OK, got it. Here's my sketch, plus some existing solar cruisers from around the world.

Aloha,

Jonathan

 

I can't wait to hear more about this project.... I've been working on NASC and WSC solar cars for a while and this sounds to me like a pretty neat project you're planning.
Looking forward to seeing how it goes....

 

Interested in brainstorming?

Hi Matt,

I was the project coordinator for a solar car school project that won a Hawaii competition and a national award in 1988 and was displayed at the Smithsonian. See the car below. My kids, a couple of years later went on to win their category in the trans Australia race.

I have lived very comfortable off the grid for many years with an independent photovoltaic based system. Never had a power outage in 15 years, while the local utility had many hundreds of failures. I know how to build bulletproof solar systems. My company, Light On The Earth, sold system components for many years.

Another company I started, Solar Marine Technologies, identified the pv powered shoreline cruiser as a good bet technically, economically and environmentally. Electric boats do not have the problems of cars because they can handle the weight of batteries and you can have a roof deck on a multihull with ample space for PV panels. There are now a number of companies making excellent electric outboards in the range of 5-10 HP nominal, but, which have thrust comparable to conventional ICE drives with three or 4 times the horsepower.

That research was done in 1996. The technologies in the meantime have improved in efficiency and durability. Now I want to build this high-tech houseboat for inland and protected waterways. Interested in brainstorming the system? I have been out of the solar equipment business since '99 and would welcome people with more current knowledge about what equipment is best in price and performance and what companies might be interested in supporting this project with donations or discounts.

I plan on spending quite a bit, but every bit helps when innovating at this level. I want to build the finest, most practical, water-going habitat ever conceived. I believe there is a huge market worldwide for a mobile dwelling that uses no fuel. Plus I want one for myself!

Here's another interesting SunBoat from Australia: http://www.cmsb.com.my/tpis/sunboat/

Jonathan

 

Good concept

Your idea is a good one. This is my first reply to a post so I'll be brief and try not to pour out my guts. Since I am also working on a similar, super-efficient river/canal boat for inland cruising I hope people will be interested in posting valuable info here.
Swath is very efficient. However the trade off seems to be greater draft and greater beam than monohull, both of which may hurt your goals. It's also less effected by waves. However, you will usually see flare above the waterline. This is what stops the rolling and pitching and keeps it on the waterline. Without it your boat will go all the way over until the upper hull hits the water unless you can think of a different way to keep it level. Catamarans and Pontoons solve that dilemma by keeping part of the vakas above the waterline (reserve buoyancy).
Good luck.

 

In what way are SWATH "efficient"?

 

Torqeedo is coming up with a new very powerful outboard watch www.torqeedo.com

 

Hmmm, a zombie thread for Halloween.

 

Agreed SWATH isn't the logical route for a vessel of this probable performance envelop.

 

haha im just gonna sit around here and watch this thread.
would be a nice boat to cruze on

was thinking of setting up a much smaller scale

 

As someone who's built a small (18ft) solar power inland waterways boat, I can say with certainty that the primary issue will be getting enough solar power and can also say that 2kW of wind power is a complete pipe dream, you'd be lucky to get 200W of wind power on a good day on inland waterways.

Panel power generation capability takes a big hit when they are laid flat on a boat roof/canopy. It takes an even bigger hit in European latitudes where the angle of the sun is relatively low for much of the day. The combined effect is that you get around 1/4 to 1/3 of the panel rated power at best, and that's using a good MPPT to get the most from the panels when charging the main battery.

My boat needs an electrical input power of around 120 to 140W to cruise at 4 mph, which is more than I can get from 200W of panels on the canopy by a fair margin. The only way it works is because the ratio of daily cruise time to run time is low. As long as I only ever cruise for less than 1/2 of the daylight hours (in sunshine, less if it's cloudy) the panels can keep the battery pack charged up.

I don't know what percentage of the deck area the 80 x 18 boat in this thread was going to have covered in panels, but bearing in mind the need to have deck area that the crew can walk around on and use for things like boarding and handling the boat in locks etc, then I'd suggest that it'd probably struggle to get more than around 80m² of PV panels. Although such an area would have a normal peak power rating of around 16kW when correctly oriented and when directly facing the midday sun, in practice such an array might only produce 4 to 6kW peak on a boat, maybe 2 or 3kW average during daylight hours. On cloudy days it may well struggle to get to 1kW.

If a 12 hours day is assumed for solar charging, then the boat might be able to get somewhere between 30 and 40kWh or so of charge in a day typically. This isn't a big energy budget for a boat of this size, and would probably mean that it couldn't operate solely on solar (or wind) power on European inland waterways.

 

I haven't run through the numbers on this size of a project, but step one would be to compare a few different solar collection strategies based on a marginal cost analysis.
The things that need to be found out are -

The lifetime you want to consider for the system.

The battery type you plan to use.

The crossover points regarding the choice of nominal system voltage on the collection side (battery management costs are strongly related to amperage and almost independent of voltage).

Suntracking strategy, choices are pretty limited for a boat at anchor or underway. You also want to put a price on each square foot of surface under consideration for panels. There will be a marginal cost associated with adding one more panel. This is either the cost of building the boat that much bigger, or the value of that space if used for other purposes. Spend some time on this idea because the cost is usually quite high. Particularly if compared to land based aps.

Don't reject the big-and-dumb approach out of hand. Wet lead batteries at 48 volts fed by several strings of panels each into a parallel arrangement of cheap charge controllers could form a baseline reference. Then see how the costs shake out when you try to boost the performance by 10% using better tech, bigger boat, lower system weight. Then look at the downstream demand. What are the costs of taking a dumb house load with no management and reducing consumption by 10%?

When all is said and done you want to generate a curve of the marginal cost (y axis) of a system of given performance covering a range of power collecting (x axis). And you want several of these representing different onboard storage capacities. The curves should be annotated with the crossover points of the different configurations, ie. the point where better panels are adopted, the point where mppt controllers are adopted, the point where lighter batteries are used, the point where you decide it's just to darn expensive and choose to add a little generator to run for an hour in the morning.

This is the primary decision for component selection- each part shall have a marginal cost relative to the next better choice that is below some threshold.

When you actually try to find components you can buy today, the number of practical arrangements are pretty small. Ie one type of charge controller will pretty much imply the use of a certain type of battery and a certain PV setup based on marginal cost. It will also determine the extent of energy efficiency and conservation efforts that should be applied to the loads. It makes sense that product designers will create products that all fit into a set of grooves based on marginal costs. That is what happens when the systems aren't integrated by a dominant manufacturer or monopoly.

Big dumb systems look better over longer time frames because the panels are good for longer times than the batteries and electronics, so keeping the shorter life components cheap and redundant makes sense.

As far as the boat goes, it should be a utterly boring monohull with minimal wetted surface set up for fairly narrow and low speed range. I'd be thinking more like a 5 knot cruise and 7 knot sprint for maybe ten minutes, perhaps with generator assist. A catamaran will have about 40% more drag at the sort of speeds you can maintain. An asymmetrical cat/proa could work at about a 20% increase in hydro drag, and maybe give you the platform you want. The propulsion specs will look a lot like the earliest auxiliary launches and their hulls are more suited to your needs than the modern hulls built around cheap diesel power. However, weight savings will pay good dividends. Play around with Michlet/Godzilla to get a feel for the hull resistance. If you took an ordinary 44' boat and added six feet to accommodate the extra junk vs a diesel, you'd probably be in the ballpark in terms of displacement and accommodations. A 50 x 18 cat would be just about the worst GA you could manage for low propulsive effort and reasonable low speed handling. You need to acquire acreage while maintaining the proportions of a low drag, low windage, built down monohull. 65x13.5 with a 50' wl and 11' wl beam would be more like it, just off the top of my head. There was a thread in the hybrid subforum about a recently launched 60' hybrid sailing cat that listed the cost of the primary systems and load management systems. This gives you an idea of the marginal costs in the vicinity of the 90%/10% area, and they are pretty high.

 

slightly off topic but on topic at same time?

do the panels have to be exposed on deck? or could they be behind a like acrylic window?
water proof ect incase get a bit of a splash on deck

 

The panels I used (pretty much like all the ones I've seen) are completely waterproof so there would be no advantage in putting them behind another clear layer. I used Sunflex panels, that are slightly flexible and only around 5mm thick, so they were easy to bond directly to the top of a canopy.

Adding another clear layer, either of acrylic or glass, would also reduce their output. Even the standard glass or plastic weatherproof covering reduces output, when compared to a raw silicon cell, by around 5% or so. The glass used on PV panels is usually toughened low iron glass, with a high transmissivity, to keep losses down.

I did try acrylic sheet with some home made panels and found that it was only a couple of percent worse than low iron glass though, so if you're looking at making panels you might want to consider it. Polycarbonate is also an option for a DIY panel, although the losses would be slightly greater than with acrylic. Polycarbonate is pretty tough though, so that property might outweigh the slightly higher loss.