Rob

The issues with Peter’s electric drives have been:

1.  The Kelly controller not being capable of reversing if the prop was still spinning forward.  Once this was realised there was the option to use the rudders as brakes but still not effective in a good breeze. One of the Kelly controllers was replaced with a 4QD controller.

2.  Lines have been tangled on the props more times than anyone would think possible.  Usually this just results in the motor stalled on rated current but a shear pin failed once. There are two relatively large deck drains without mesh that allows untailed lines to wash down and they can eventually get to the lw motor.  Then there is the errant mooring line and so on.  

3.  The ww unit was mounted lower than desirable because it was packed down lower than design to cater for the slope in the bunk floor.  That eventually resulted in the lid on the motor housing corroding and losing its seal because the motor housing was submerged in normal operation.  There was a subsequent issue with the ww unit because the shaft tube o-ring was not fitted correctly on the first repair.  No water issues with the lw unit.  

Pivoting the drives out of the water when not in use has no doubt reduced maintenance issues.  

The $120 farm spreader gearboxes used have been surprisingly reliable despite being immersed when operating.  They were modified to have a stainless steel prop shaft; the deep groove bearings on the prop shaft were replaced with angular contact bearings; the single lip prop shaft seal was  replaced with a double lip seal and the boxes are grease packed rather than oil filled.  

When Peter was looking at the bigger diesel I suggested he should reconsider diesel sail drives.  There were still many challenging issues with that option such as the width of the lw hull; the mess of a motor inside the ww hull; still not confident about the immersed legs when sailing fast backwards due to the water intake pressurising then flooding engine cylinders via the water cooled exhaust; losing the ability to ground without damage but mostly the poor experience with other boats using sail-drives.  Did you know the legs on Ozone needed overhaul after little more than a year!  Access to an engine in a narrow hull is challenging. I had reasonable experience with the one sail drive I used for a number of years but forgetting to leave it in gear when moored for and aft in a fast flowing tidal creek for a period caused the shaft bearing to wear out over a matter of months.  Sail drive owners often need to deal with water contaminated oil in the leg; hard to do without slipping.

Rick

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