Why stop at the model, why not design a solar powered cruise liner?



The 22ft model of the Titanic shown below is the work of Kevin Cassidy.  Kevin lives on beautiful Lake Boon in Stow, Massachusetts.  He wanted a boat for gracefully cruising around the lake - something quiet, non-polluting and just a little bit different. No existing boat he saw met all his requirements. So he built his own and named it the "Solartanic."  The superstructure raises up to allow entry to the vessel.  This boat is not directly solar powered as with the Planetsolar, but its batteries are charged while docked or in dry dock, so it qualifies as solar powered.




Kevin on Lake Boon in his giant model of the Titanic


  • Is anyone else interested in a silent, eco-friendly replica that is also a practical launch, Kevin wants to know if there is enough interest to support low volume manufacturing of a production version.

  • He's also a proponent of alternate energy, but you need to be clear on the limitations and trade-offs involved. A solar electric boat provides a good case study of some of the issues.

  • narrow hull for easy cruising on low power

  • electric propulsion with solar panels on the dock for recharging the batteries

  • inspired by early 1900s fantail launches, modified slightly to mimic a certain 1912 ocean liner

  • Its a convertible that carries 2 people top down, 6 people top raised (see photos)

  • and it looks really cool at night due to lighting display.




Length:       22'

Beam:          4' 5"

Draft:         14"

Weight:      900lbs (empty)

                1900 lbs (loaded


Passengers:       2 people in replica mode

                       6 people with top raised

Power:             Two .75 hp 24 volt electric motors giving 54 lbs of thrust


Battery:           4 marine deep cycle = 100amp/hours @ 24 volts


Speed:            4 MPH (cruise) @ 20 amp draw
                      5 MPH (max) @ 45 amp draw

Range:             Approx 15-20 miles @ cruising speed

   Prototype used "Stitch and Glue" construction with 3/8th inch marine grade 

                      plywood. Any production boat is likely to use a more hydrodynamic molded hull.





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It's not the result, it is also how we got there that is so interesting. Clearly, Kevin improved his facilities as the project progressed, from this makeshift tarpaulin with pole supports, to the much more spacious framed unit below.






We like the hinged deck to allow the skipper entry - and note the side mounted rudder controls






The location for this kind of project is perfect. Lake Boon is clearly visible just a hop, skip and jump away.




The two 70 watt solar panels used to charge the Solar Titanic, along with a controller and wiring cost about $700. This will support about 2/3 of a horse power for 10 hours a week during the long days  of summer. Kevin installed the panels on my dock, but says that people expecting a couple of solar panels and 4 storage batteries to be a replacement for a 200 horse power outboard motor will be greatly disappointed.


Electric powered boats based on lead-acid storage batteries are viable as long as you don't need to go very fast or very far (water skiing will have to wait until fuel cells finally become viable). But if you are looking for quiet, casual cruising then electric powered boats make a lot of sense.

So now lets look at the whether or not solar panels make sense for a small electric boat. The previous pages established a bit of background on how I view alternate energy questions in general. The same basic rules apply to pretty much all alternate energy projects:


You have to be hard-nosed and realistic about:
1) how much energy is really available
2) evaluating your energy requirements
3) understanding how well the two match up.


Kevin says: "I found my solar panel by cruising the web. The going rate for new PV (Photo-Voltaic) panels seems to be a bit under $4 a watt. I wound up buying a 70 watt panel for $269.00. This can produce a maximum of 70 watts if full, unobstructed sunlight is shining at a right angle onto the panel." 


1) How much energy is available?

  • if the sun is more than about 30 degrees from a right angle the output falls off fast.

  • if it is an overcast day, the PV panel will only produce about 30% of rated output.

  • a "12 volt" panel is typically 36 solar cells in series to produce the 17 or 18 volts needed to charge a 12 volt battery. Even slight shading from a cable stay (for example) on a few of the
    cells will significantly reduce output.

2) What are the energy requirements?


The latest edition of the Solartanic uses two 24 volt, 54 pound thrust Minnkota trolling motors.

  • At full power the motors draw about 45 amps@ 24 volts = 1080 watts while pushing the boat just under 5 MPH.

  • Cruising speed is defined (rather arbitrarily) at 20 amps@24 volts or 480 watts which pushes the boat just under 4 MPH.

  • Note that 1 HP = 746 watts so full power works out to about 1.5 HP, although in practice the motors are not 100% efficient.

  • Kevin currently has four 12 volt marine duty batteries (arranged in 2 pairs to produce 24 volts) with a realistic capacity of 100 amp hours. So I can get a bit over 2 hours at full speed
    or 4 to 5 hours at normal cruising speed out of a charge. The boat still moves along nicely at 10
    amps in which case the batteries last about 10 hours. The boat could easily hold two or three
    times as many batteries if needed, but Lake Boon is not very big so the current battery capacity
    seems adequate.



And finally "kitty" (Frisky) gets to investigate solar power - which she says is not as interesting as tuna or go-cat.



3) How well do power requirements and availability match?


Directly powering the motors from solar panels is an expensive and inconvenient proposition:

  • Full power would require at least fifteen 70 watt panels (at close to $4000) and then only under the most favorable conditions.

  • Even cruising speed would require 7 panels, again under ideal conditions.

  • If we wish to maintain cruising speed when it is cloudy, we need three times as many panels. Even then, what do you do when the sun goes down? Or when shaded by trees on a small lake
    or river?

  • Mounting 7 panels that are roughly 2x4 feet (let alone 15 or 21 panels) on a 22 foot boat is a bit of a problem (particularly if your trying to maintain the profile of the Titanic!)

After initial investigation, Kevin quickly disregarded the idea of mounting the panels to the boat. It just didn't seem practical: it was too expensive and certainly didn't fit the "look" he was after. There are  boats on the web that do run directly from solar panels, but they tend to have large flat surfaces for mounting them. Catamarans are often popular for this type of boat since they provide a lot of square footage and can provide a somewhat higher cruising speed at low power.

The obvious alternative is to run on batteries and mount the solar panels to the dock instead of the boat. It is (usually) much easier to orient the panels to maximize the energy collected. Since Kevin lives right on Lake Boon, his boat, like many pleasure boats, will spend most of its time at the dock where the panels can charge the batteries. Kevin estimates on how he typically uses his boat:

  • an hour after work a couple of days a week for a sunset cruise if the weather is nice.

  • four hours on each of the weekend days

He picked 10 hours a week as an average utilization.


Two 70 watt panels (in series to provide 24 volts) can provide a maximum of 140 watts. Making some allowance for less than perfect efficiency, it takes 4 or 5 hours of good sunshine for each hour of cruising at 480 watts, or between 40 and 50 hours a week. Given the long days of summer, an average week should provide enough sunshine to support 10 hours of cruising. Kevin's experience at the end of last summer (with the Solartanic's original 12 volt motor and single solar panel) seemed to confirm this estimate. He recently received his 2nd solar panel and will be observing the new setup as soon as he gets it installed.


Is it worth doing this? The panels cost about $540 and will be generating about 50 cents of electricity per week. However it would cost several hundred dollars to have an electrician install a GFI protected line down to the dock so, Kevin decided the solar panels were worth it. So the short story is:

  • $700 worth of solar panels, controller, wiring etc will support 2/3 of a HP for about 10 hours week. If this meets your requirements, it may be cost effective if you don't already have 120 volt power at your dock.

  • As with most forms of alternate energy, you must be willing to live with the statistical averages unless you have a backup power source.

  • The Solartanic will most likely only exceed the averages if I trailer it away from Lake Boon to show it off. If the boat is in my drive way on the trailer its easy to hitch up the battery
    charger and charge the batteries using house power.






Firstly, we share Kevin's interest in the Titanic and he should note that the Australian Entrepreneur, Clive Palmer, is planning to build the Titanic II - so we are not alone. This was a truly epic project that took over the lives and living room, of Kevin and his (extremely tolerant) wife. The results are well worth the effort, and yes we agree with Kevin that a production version should have a more efficient hull. You may find takers in an environmental theme park. Technology is advancing to the stage where solar ships may well ply the oceans one day soon. it all depends on political will.





Kevin lives in an idyllic location for boat lovers as you can see from his photographs - lucky man. Kevin says that he is interested in almost all forms of alternative energy and almost any boating topic. If you have comments on his project you can e-mail him directly at:

Kevin Cassidy
10 Davis Rd
Stow, Ma 01775 



All of us here at Solar Navigator would like to congratulate Kevin Cassidy for sharing his practical experiences with the boating community - Nice one Kevin.


Links to suppliers:

Electric Boat Links:

Electric Boat Association of the Americas

Electric Boating

Don Robertson's Marine Marketplace

Boat Owner's electric boating links

Electric Boats and Outboards

Titanic Links:

Titanic Research and Modeling Association

Encyclopedia Titanica

Titanic in 30 seconds, re-enacted by bunnies (very funny)




Solar Titanic





A taste for adventure


The $Billion Dollar whale, adventure story with John Storm


A heartwarming adventure: Pirate whalers V Conservationists, 

with an environmental message.

For release as an e-book in 2013 with hopes for filming in 2015 TBA




Titanic documentary  - Youtube


Britanic sister ship - Youtube





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