Duffy Electric boats....?

Are there any Duffy Electric Boat people still on this forum? I own a Duffy 18 (1992) and I am in the process of restoring it. Thanks, Doug

Thanks Rob! Great to know. I have a 1992 Duffy Electric 18 footer. It is mostly restored and I am in process of updating the entire motor assembly area, electronic controller, etc. and cutless bearing.

Here is the "before" image of the motor area. The motor is about 2 years old but everything else needs updating.

Thanks Rob,
I love your boat too! I was not familiar at all with that style of Duffy! It is great. Do they still make them? I think it would be an extremely popular design. As you say, perfect for cruising and enjoying some refreshments.
Thanks again for getting back to me. My plan is to have parts for my rebuild later this week and then to get going.

Thanks Rob, I will for sure post some pictures as I proceed with additional repairs. So far, I have done the following:

• New batteries and motor (installed by the previous owner in 2020
• New motor controller - I installed recently - the old one worked somewhat but was failing
• I am replacing the cutless bearing by the prop
• I am refurbing the motor area to include a new large sheave/pulley, new front bearing, and new dripless seal. I will also clean up the entire area.

Thanks, Doug

Hi Rob,
It had an old Curtis 1204-413 controller in the boat when I purchased the boat. I guess very similar to what is used in a golf cart like the motor. It worked but the key switch for the boat did not turn it off and when the controller was cold it would not run the motor sometimes. After a Google search I found a company called Flight Systems Industrial Products (FSIP) who makes direct replacements for Curtis controllers. I had also contacted Curtis I seem to remember and they directed me to FSIP. The replacement is a new unit although they also will rebuild your old controller too. It was expensive at $577. However, it works flawlessly and was an easy drop in replacement. FSIP is at www.shop.fsip.biz I put in the Zapi FS5050 number on their site and they seem to handle it as well. They have a chat function on their website and might help you?
Thanks again and I will keep you posted. Doug

Thanks for your help last summer with the motor bearings. This summer I need new batteries for our ElectraCraft LSR 18. It is a 48V system current using six 8V golf cart batteries.

I'm considering switching to four 12V batteries such as the attached from Costco. Can anyone comment on switching to 12V batteries? We use it on a small lake in Colorado so range is not an issue, my goals are lower cost replacement and ideally not needing to bring them into the garage in the winter.

Cheap batteries will have to be taken in and out of the boat frequently, just to take them to the recycling dumpster.

Batteries, like many things in life, are "You get what you pay for". Good quality ones have thicker plates that last longer.

I don't know who wrote this about AGM Deep-cycles but I agree with them entirely.

https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/#AGM, or Absorbed Glass Mat Batteries

Thanks Fishtigua, that was convincing. I've been thinking about this wrong and am now happy to pay 4x for a battery that lasts twice as long and doesn't need to come inside in the winter.

I'm hoping for some help with my electrical calculations. My motor sticker is below, it says 95 amps. Despite saying 72V, I believe this has always been a 48V system using six 8V batteries. The existing 8V batteries each say 145AH @ 5 HR, so the combined six battery system would be able to output 174 (145/5 * 6) amp-hours for 5 hours, correct?

I’m converting to four 12V batteries and want to have 2 hours of runtime (our lake is very small, one hour is the actual max). At 95 amps I need 180 amp-hours total, or 45 amp-hours from each 12V battery, correct?

This from West Marine:-

Battery capacity measurements are commonly expressed in Amp-hours (Ah) and Reserve Minutes. Amp-hours measure the total amount of energy that a battery can deliver for 20 hours at a constant rate of discharge before the voltage drops to 10.5 volts. This means that a 200Ah battery can run a 10A load for 20 hours. The reserve minute rating is the number of minutes that a battery can run a 25A load until dropping to 10.5V, just like with starting batteries. A Group 27 deep cycle battery with a rating of 180 reserve minutes will run a 25A load for three hours. House loads range from 5A to 25A or more. Amp hours is generally the more relevant measurement for house banks.

Thanks Rob. My boat (an ElectraCraft not a Duffy) came with my house and since I've owned it has always had six 8V batteries (T-875s). I appreciate you correcting my multiplying Amp-hours and I think I understand now.

I'd like to switch to AGM Deep Cycles for the many benefits in Fishtigua's link, especially the no maintenance and surviving a freeze.

Assuming I am going AGM, I'd appreciate any comments on the pros/cons of using four 12Vs vs six 8Vs as well as recommended brands.

I appreciate the previous help. I went with four 12V AGM batteries, the precise model is "Centennial CB12-85 12V 85Ah Group 24 Sealed Lead Acid AGM Battery"

Total cost was $1,035 from battsys.com (local pickup in Denver). My son and I installed them today and they are working fine, hopefully they last many years.