Re: [electricboats] Supplementary electric power for heavy old sailing boat

Hi Matthew, 

Would you plan to somehow disengage the belt to the pulleys when using your diesel motor?

On Sep 3, 2020, at 07:24, Matthew Cook <matthewcook40@gmail.com> wrote:



Hi folks,

I'm new to the group and enjoying reading old posts and learning a lot about electrifying boats.  This may have been covered in older posts so please excuse me if I'm bringing up something that has already been discussed but I would like to run some ideas and questions by ya'll:

• One of the differences between a 1984 38,000lb heavy cruising sailboat like my Liberty 458 and a modern cruiser/racer is that the cruiser/racer will point into the wind on a beat about 20-30 deg higher than I can.
• Another difference is that unlike many "plastic fantastics" my old boat is very comfortable, seaworthy and affordable.  In all but sailing performance, I prefer her to something newer and with better performance.
• I love to sail when possible but I'm no purist and if I can cheat without compromise, I will.  I'd like to add a 10Kw electric motor to my existing drive train so that when I'm beating, I can turn my fixed 3-blade 20" x 15" propellor enough to help my sailing performance (my transmission is a Borg Warner Velvet Drive and can freewheel without any problem).  I estimate 2-3kw into the drive shaft would be sufficient in most conditions to bring my sailing angle up to around 30-40deg off the wind which would keep my impatience in check.  When there is no wind, I may also use the "2nd auxiliary" to keep me moving rather than start the noisy 84Hp Perkins 236 engine.  It would also be very nice coming into harbor when crew are line handling and we can hear each other without having to yell over the engine.

Some questions that I have:

•   Has anybody done something similar to this?  Can they report on their results?  
  
•  If I placed a BLDC motor with a 2:1 dual belt drive to two pulleys over my propshaft, it would apply some side load to the shaft which would, in turn, be applied to the bearings of the transmission and the Cutless bearing.  I'm confident that the load on the transmission would not be a problem but I'm not so sure about the Cutless bearing.  Does anybody have any experience with this?
• Would I need to include pillow blocks on the output shaft of the motor or can the motors generally handle the side load of placing a pulley directly on the output shaft?
• I'd love to use the system to regenerate also.  I've read how regeneration is not very efficient in smaller boats but, with sufficient wind, I can consistently hold 7knts throwing a pretty big wheel.  I know from experience trying to stall my prop shaft when I'm running along that there is a lot of power there!  Other than an old-school brushed DC motor, is there any motor that will do a better job of regenerating than another?

Thanks in advance for any thoughts.  

Matthew