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Mundoo 3 Solar Electric
11 metres x 2.5 metres
12hp Permanent magnet electric power
Top Speed 8-9knots
or 10/15hp 4 stroke outboard
Top Speed 10-12knots
Solar Mundoo 3 along the Murray River Cliffs
click images for larger views |
A couple of years ago I was burning the midnight oil on a huge job for Duck Flat Wooden Boats, but happily (and with a great sigh of relief) I finally (December 1, 2005) handed them 22 detail drawings plus documentation on the building procedures for their Solar Electric Mundoo III riverboat.
The boat was featured in Woodenboat magazine and they had faced a growing demand for plans, so had been cracking the whip (in the kindest possible way) in my direction.
| Original Mundoo 3 |
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The original boat's hullshape was based on the existing 4 stroke outboard powered Mundoo 3, but in a sense, grew organically out of the collaboration between the Ducks and the owners John and Gabby - with just about every aspect of the boat changed apart from the main hullshape.
The main hull remained the same shape, but gained a raised foredeck for much more volume in the forward cabin, a nacelle beneath the main hull was added to carry the batteries, motor and prop shaft (other major changes were - a bow thruster was fitted, the cabin extended aft, the galley enlarged and much shifting of interior spaces - not one bulkhead from the original design remains in the same position).
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Mundoo 3 Outboard |
The boat is a great success in every sense - it far exceeded the technical expectations of the hybrid electric power with a higher cruising speed and a higher yield from the solar panels than expected. On a reasonable summers day the "break even point" where the solar panel output equals the motor's consumption is at about 4.5 knots.
| The electric motor in its nacelle compartment |
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The original brief was for the solar power to be heavily augmented by hooking up to shore power most evenings of a cruise, but in actual use has proved to be much more independent of outside power sources than expected.
There is a portable generator aboard if things get really desperate, but it hasn't been used a great deal so far.
As almost every detail of the boat was revised from the original the Ducks asked me initially to document the boat during the building process so they had the information to build further boats.
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Solar Mundoo 3 from the Stbd quarter |
Then when the founder of Duck Flat, Robert Ayliffe, got the opportunity to submit a major article on the solar version for "Woodenboat" magazine it quickly became clear that there was a large demand for plans.
Enter Storer (er, me) and his trusty* computer to turn the documentation of the hull into a full plan that a first time builder could follow as well as providing preliminary drawings of all the variants.
*(or not so trusty - as it turned out - it died halfway through the building process, but no data was lost!). A note on computers - I do all my design on a three year old laptop - when the old one died I was able to pick up another for about $320. Probably little more than getting a tech person to look at repairing a newer model.
It really goes to show how the hardware has sped ahead of the software. In other words - if you have great design ideas but someone tells you that you need a squillion dollar computer and squillions of dollars of software - ignore them and get stuck into it. It's all about the ideas - the purpose of the computer is simply to transform them for distribution.)
It is some time since I have done a plan of this complexity, so I had forgotten how the complexity somewhat overwhelms one; the effort of holding the interrelationships of dozens of parts in my mind's eye is rather intense - eg, just how the parts attaching to one bulkhead relate to the adjacent bulkheads, or when finding that some crucial part like the cabinside is wider than normal plywood dimensions and then having to go through and change just about every drawing.
| Mundoo 3 Solar Electric |
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The advantage of designing on computer is considerable, allowing a huge amount of extra detail to be incorporated in the plans. Comparing the original Mundoo drawings (developed the old way - on paper) with this new batch is like chalk and cheese - it makes it infinitely easier (OK I am exaggerating ... much easier!) for a builder to make an accurate boat with huge labour savings as the builder can see EXACTLY where that next bit of wood goes. It is all left a bit up to the skill and imagination of the builder with conventional drawings.
Such is life.
Anyway . . . a truly great boat - I had a good look on the net at the time and I think this was the most fully developed electric boat plan available. It is a real boat for real use (and IS being used as I speak (write) cruising the Murray River and its extensive backwaters) and must be one of the largest commercially available solar boats (or plans) available.
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The smaller and simpler Mundoo 2 |
It was great to be involved! Thanks Duck Flat! Thanks John and Gabby!
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