Re: Ang.:Re: [electricboats] Sizing motor for 45-50’ boats

Amazing thoughts! Thank you so much for all this information. I'm plodding along an slowly progressing.  Here are my existing thoughts. Dan, I'm planning on riffing from your plans, spinning the engine to the other side, and doing a few other things.

Here's my latest thinking for getting my 55' sailboat on electric. It's based on all the wonderful feedback here!

After much thought, I've decided against using a transmission and am going to go with a pulley system. It's just simpler, even though I lose the ability to have a neutral (which would allow my auxiliary shaft to be used for an emergency pump). That decision was driven by the advice of the good people on this list. Thank you!

However, I'm planning on mounting my engine the opposite direction of everyone on this list, and I thought I'd explain why, in hopes of getting feedback from folks.

Here's a very, very ugly diagram, not to scale, made by cutting and pasting.

 

I'm going to go with off the shelf components where possible. That's one reason for putting the Spindle facing forward – I won't have to machine it, and it puts the larger bearings where they will accept the forward thrust (which for me is more common).

Initial (potentially incorrect) thoughts:

• Put thrust plate AFTER large belt spindle – given the limited forward and backward slip from the Hub, I don't think that will cause issues with the belt slipping off (1 ½" belt, I believe)
• Orient the Hub and Spindle with the 'wheel' side facing fore – this means no metal working for me, places the biggest bearing where it will take the forward thrust and simplifies installation
• Orient the motor on the fore side of the mounting plate – this is necessary to get the belt and gears on the same side, plus I have more room on this side of the plate if I decide to mount the plate, motor and gears at a 45 degree angle to starboard to get more space in the engine room
• Use the 6000 lb hub and spindle – this gives me the capability to support more thrust. 
  • Rule of thumb of 20 lbs force for every HP gives me 2000 lbs force, which is within tolerances for this hub and associated bearing.
  • Hub: Kodiak Trailer Hub for 5,200-lb to 6,000-lb Axles - 6 on 5-1/2 - Stainless Steel Kodiak Trailer Hubs and Drums KH42655S (etrailer.com)
  • #42 Spindle: #42 Spindle for 5,200-lb to 7,000-lb Trailer Axles - 2-1/4" Diameter TruRyde Trailer Spindles TRU57FR
• Use a motorcycle kit for my sprockets and belts – I'm looking for a 5 to 1 reduction, and that's really hard to find on Grainger without having a really small engine sprocket. The Zero motorcycle is an electric motorcycle that provides torque only slightly less than the Hyper-9, so I thought it would be a good solution. It's made for providing power transmission and has a reduction ration of 4.5 to 1 which is good enough (20 teeth to 90 teeth).
  • Zero Motorcycle Wide Belt Sprocket Conversion Kit - Luna Cycle
• Tighten with one or two idler pulleys – not sure if I will have enough space to tighten much, so will likely need to get belt pretty close to the right size if I even change the engine sprocket to change the reduction ratio.
  • In the worst case, I can have one pull in, and another pull out, but that's not ideal
• Battery box will be custom built, as I have 48 Lishen (similar to Eve) 280AH batteries that will take up a lot of room. They will end up on the stays with supports to allow walking on them when I drop into the engine compartment.  Should I call that a motor compartment now? ;-)

Thanks so much for everyone on this list. Dan, I'm really happy you started this thread, and Carsten, you have so much wonderful knowledge. And everyone else has such valuable experience and insight.  Thank you!