Is This The Future?

Is This The Future?


Esc.Key is a new solar electric riverboat recently launched by Denman Marine Australia.

The initial design brief was for a river launch that was similar in concept to the early 20th century Noosa River putt-putt boats which had a hard top to keep the harsh Queensland sun at bay.

The boat is constructed from strip plank western red cedar on celery top pine structural timbers. Fit out is Tasmanian blackwood and Huon pine. Decks and sole are laid teak. The hard top is 25mm core cell foam/western red cedar and celery top pine. She has a beautiful birds eye Huon pine table aft that lowers to form a day bed for those lazy afternoons.

She is powered by a Mastervolt Drive Master ultra 3.5kw 48V AC motor which pushes her along at a nice cruise speed of 4.5kts with max speed 6.5kts. She has a 450Ah 48V AGM battery bank which is fed by 1000 watts of thin film, high output Solbianflex solar panels on the hard top. At full charge, the boat is energy neutral at 4kts.

The engine was small enough to have it completely below the sole and the set allows you to cruise along with no noise/fumes or the smell of diesel, definitely the way of the future.


LOA (feet): 23′


Beam (feet): 8′


Type/Rig/Power: electric powered river launch
Home Port: Noosa, Queensland , Australia
Designer Name: David Payne/Imagineocean Yacht Design/Denman Marine
Builder Name: Denman Marine
Launching Date: February 18, 2014


5 thoughts on “Is This The Future?

  1. Denman marine built our swallow boats Bayraider 17 day sailer for us and shipped her over to Auckland. They are top notch.


  2. Thanks for the response Murray. Interesting.
    I will tread with caution. Most of my research has been on Google and Utube.
    Last year I helped sail a quick Granger Catamaran 7000mls back to NZ from Indonesia. We motored nearly 50% of the time using 1 of 2 8hp Honda outboards which pushed us along at 5knts and so the electric seed was sown while listening to a screaming outboard.
    Our average speed for the whole trip was 5.75knts and VMG was 4.75knts. Makes you give up on using wind after 3+ months.
    Mike E


  3. Hmmm, ideal for cruising the viaduct or on a lake, however with our distances and weather you must consider all factors, for example one recently featured open ‘electric’ boat in NZ runs at approx. 5 knots burning more fuel than I burn petrol at 12 knots when you calculate their genset use. Also I know of two trad yachts that converted to electric, then had to remove it all and go back to diesel, these facts aren’t advertised of course as it cost the owners a fortune, the main promoter of electric propulsion for cats in the states has gone bust – twice. We are getting there, but not quite yet, and that’s without mentioning the lithium battery fires …..


  4. Nice boat to build and use. So much room for a 23′ boat – particularly with out any engine box protruding above the sole. Now I just need orders for a dozen more………


  5. I think we will see a lot more of these electric engines as costs come down. It makes so much sense to me to cruise in a quiet, comfortable and economical manner with minimal maintenance.
    In the States they are converting older 40 to 48′ sailing cats with 9kw motors, batteries, and 3 to 6kw of solar panels for about US$50K. The old 28hp or larger sail drives are removed and shafts fitted giving the boat better performance than before.
    Of course you need aircon and other electrics like coffee makers so a 6kw inverter is installed and a genset is added at extra cost.
    The result is a big boat that is fully charged when you step aboard and can cruise energy neutral on a good day at 6knts. Not a bad average speed for most yachts and the cost of the conversion is probably less than the rig. Travel at night you would have about 2 hrs running on batteries before the genset was needed.
    The efficiency of these hybrids is very good and a rule of thumb is that the horsepower can be halved for the same performance due to the gensets operating optimally, larger props, more torque, no gearboxes and so on. The 9kw (12hp) electric engine conversion out performs the 28hp Volvo sail drive.
    I hope to find a suitable boat to convert next year, it may be a woody but I’d have to hide those solar panels from HK somehow.

    Mike E


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