WOMBAT is a cold-molded version of William Hand’s Piute III design, built by H&H Boat Works in 1992. When she arrived at our shop, she had already been converted to electric propulsion, but her owner was not getting the reliability or performance he expected.  The existing system overheated frequently, and the temporary fix was to reduce the motor’s maximum output from 15 kW to 10 kW.  Even before that reduction, the boat had fallen short of his speed and range goals.

With those goals in mind, we designed a new system to deliver the power, range, and confidence he was looking for.  Estimating the right motor size required some careful judgment: WOMBAT’s hull design dates back to the early era of planing boats, and the old motor never produced enough power for meaningful testing at higher speeds.  Our experience with Harry Bryan’s Handy Billy – a similar boat we have built several times – provided the best guide.  Though those boats can typically reach about 15 knots with modest power, WOMBAT is longer and more than twice as heavy.  After weighing the variables, we determined that 40 kW was the right target.

For the repower, we selected ePropulsion’s I40 inboard: a water-cooled, 96V, 40 kW motor, paired with two ePropulsion G102-230 batteries providing 23 kWh each.  Nautilus Marine supplied a new stainless steel shaft and bronze propeller.  In anticipation of higher speeds, WOMBAT’s owner also asked us to add full-length spray rails and wedges.