Electric propulsion

[Noah]

Ok, I searched him out. Here is a link to his thread. Very interesting.
https://www.facebook.com/groups/catalina34enthusiasts/permalink/1443257403119380/?mibextid=W9rl1R
Hopefully you don't have to join that group (I did) to read it.

[Jim Hardesty]

With my M25XP engine - on two occasions I've had a marina owner and on another a dockmaster say to me when I was throwing off my bow lines, "Aren't you going to start your engine"? which was already running!!! The moral of that story is that you can get the M25XP to run smoothly and quietly!!

Ron, I've also had that happen.  Shamrock's M35 is smooth and certainly quiet enough to have a normal conversation when motoring.  The engine room blower does add to the sound level but that can be turned off.  Much quieter than my Honda 2000.
Jim

[scgunner]

Robert,

I've found that doing your own engineering to be very expensive and the results usually hit or miss. I'd try to find someone who did what you want to do hopefully more than one since it sounds like you're already committed in a big way.

I had a friend several years ago who purchased the boat he'd always wanted, his wife Nina was not happy and said she'd never set foot on the boat. So he named his boat "NO NINA"! You've always got options.

[robertr0816]

Carbon, the motor is not really meant to be run at 100%.
If I want to achieve 4 knots, the 20kw bank should give me several hours of quiet motoring or i can turn on a generator and help the bank along. A 5kw pulsar generator would be able to supply the 30amp to the battery charger and also allow me to run air conditioning, with no issues.
Below is some data of a 32 foot Pearson with the same motor I purchased. I think with electric propulsion, you have to design it for the purpose you intend to use. All I want is to be able to go around long island.
If I was cruising down to the caribeans, then I would add a kubota generator and run a hybrid system.
32 feet Pearson converted

[Steve McGill]

Noah posted the full Facebook link for the 86 electric conversion. It's currently or was listed on Boat Trader

https://www.boattrader.com/boats/make-catalina/model-34/fuel-electric/

[High Current]

I'm currently working on turning mine into a parallel hybrid with the M25XP...slow-tracked while I clear a backlog of other projects.  I previously converted a Hunter 25 to electric and have done a bunch of hull drag and prop calcs for both it and the Catalina.  PM me if you're interested.

Be careful with battery placement as it can affect the trim of the boat.  My old Hunter had a distinct backwards lean with just 72V x 100Ah mounted under the cockpit.

For general motoring, 3-4 kt is a good speed.  Anything more just starts wasting power.   400W of solar charged me during the week and generally kept up with me while cruising - even though I installed an induction stove to replace the portable Coleman.

That said, an electric auxiliary encourages you to use the wind whenever possible.  Motor sailing gains a new relevance.  400W can counteract your morning coffee and getting under way, but would be agonizingly slow without the battery to save it up for shorter bursts. There is still something to be said for a diesel that moves you endlessly in a straight line at 5-7kt when you just want to be somewhere.

[robertr0816]

I am looking for a favorable place to have the large battery bank.

The dimensions are 38"Long X 15"Wide x 10 height.

what do you guys think would be the best place?. all tanks on the boat are going to be replaced so i have many options. Keep in mind, i wont have a gas tank.

[Carbon]

I am looking for a favorable place to have the large battery bank.

The dimensions are 38"Long X 15"Wide x 10 height.

what do you guys think would be the best place?. all tanks on the boat are going to be replaced so i have many options. Keep in mind, i wont have a gas tank.

I'm wondering what the battery bank weighs. It would seem the weight would have a big impact on the importance of its location.

My back of the napkin math says it should weigh about 300 Pounds.

Could you put it somewhere near where the engine is? That would keep it low and on the center line. That seems ideal.

[robertr0816]

For the 48v bank We are looking at 308lb.

I will also replace the old 12v bank and add 2 12vlifepo4,could be 130 pounds.

[Carbon]

This seems like a classic aircraft Weight & Balance problem. It's not very hard, just need to know the weight and arm for the items being removed & installed. Also need to know the boat's current CG (center of gravity) with respect to some "datum" (bow, stern, mast).

Once you have all that it's just arithmetic to know how much you've moved the CG. Ideally I think you'd like to keep it the same to make sure she still floats on her lines.

If you would like to math this out, let me know, I can help.

[robertr0816]

Thank you carbon.

I was thinking of starting with the liquid weight the numerous tanks theoretically have at capacity.
On my c34 we have the two water tanks. The diesel tank and the blackwater tank.

Plan:
Removing diesel tank.25 gal.(at capacity is 175 pounds)
Removing the waste tank. 30 gal.(250 pounds at capacity)
I can remove one of the water tanks.

My first inclination is to place the 48 bank where the waste water tank is.

[Carbon]

If you look at the weights of things, this is what I'm coming up with

Generally Aft:

Diesel: 25 gallons @ 6 pounds per gallon plus the weight of the tanks & plumbing. 175 Pounds sounds about right.

Engine: Universal 25XP, 285 Pounds. Plus Muffler and other plumbing & Fittings. Estimate total 400 Pounds

Generally near Center:

Waste Tank: 30 Gallons at 8 pounds per gallon (240) plus tank & Plumbing. Around 275 pounds

Forward Water Tank: 26 Gallons, 208 Pounds. Plus tank & plumbing around 235 Pounds in total.

In general terms, you are removing 575 pounds that are generally aft and around 510 pounds that are generally near the center. What we don't yet know is the weight of the electric motor, controller and the various wires and dodads. Taking it all out, the boat should remain pretty well balanced.

Where to put the big battery? Probably anywhere would be Ok given the relatively balanced weight coming out.  However, I still think putting it behind where the engine was would keep it low for stability and keep the heavy wire runs short. And it would probably be the best place for balance.





 

[Phil Spicer]

Don't forget, the early boats have a port list. A little more weight on starboard could help overcome the port list.
Just another thing to think about as you balance the boat. Good luck with the project.
  Phil