Luke, See attached photo of the closest thing that I've tried to what you propose. It's a 36v MotorGuide, 96 lbs (I think), and it worked good. The boat is about 2500lb. Cat. As you can see, I hinged it to get it up out of the salt water I sail in. Made about 4 mph...good enough. Sold the boat soon after install so no long term report.
Glenn Holland
From: Luke Johnson
Sent: Monday, January 03, 2022 9:46 AM
Subject: [electricboats] trolling motor lower unit
I'm very happy to have found this group packed with such great people with so much valuable knowledge!
I am a fairly new owner to a '79 Catalina 30 with an old Atomic 4 and I'd like to go electric.
For context - I sail on Georgian Bay, Canada. My goal is to explore the bay in a conservative, comfortable family cruising sort of way.
I have this crazy idea of mounting 4 or so 101 lb Minn Kota lower unit pods on the bottom of the boat. Here's the link to the pod:
https://www.ebay.ca/itm/272728816739?epid=1953153684&hash=item3f7fe77c63:g:MpEAAOSwU~9hJQI5
Looking up the specs on the Minn Kota 101 lb model, it appears to draw 50 amps at 36 volts max, which is 1800 watts.
I'm thinking of using 4 of them for a 5.4 kw system and 400 lbs of thrust. This seems to pass the two 'rule of thumbs' I've seen:
- Minn Kota site: 2 lbs thrust for every 100 lbs displacement
- - (10200 boat weight/100)x2 = 255 - - this system would have 404lbs (across 4 props)
- 'electric boat' rule of thumb of 1 kw / 2 tons
For mounting, I'm thinking I could drill a hole for the wires, and on the outside of the hull fibreglass in a threaded pipe that the pod would screw on to. Probably mounted beside the keel to avoid haul in / haul out straps catching them - and to be close to the boat's pivot point to help with maneuvering.
The possible benefits I see are:
- no noise or space in the cabin
- more efficient than a single motor due to more prop contact with water - ie - more range vs a 1 prop solution?
- cooling would not be an issue
- would push the boat at least 5 knots
- would be possible to make regen work
- would allow excellent maneuvering control in tight marina spaces
- excellent redundancy
- simple, cheap motor controls
- all components are max 50 amps
- easily available parts / replacements
Possible drawbacks:
- would need occasional brush maintenance - pods could be inspected when boat is pulled each winter
- lots of drag. Not a bad thing if regen could be made to work.
- ??
I would truly appreciate any input anyone has about why this would be a terrible idea so that I can get it out of my head haha!
Thanks!
No comments:
Post a Comment