Author Topic: Conversion to inboard electric propulsion  (Read 4790 times)

Offline garinel

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Conversion to inboard electric propulsion
« on: February 28, 2013, 05:57:08 PM »
Hi, CP 25 owners!
I bought my CP25 almost 3 years ago (Hull #34). She is a 2001, with outboard motor and tiller steering, sails Barnegat Bay and has been nothing but a joy. The only thing I am not very fond of is the outboard motor, a Honda 9.9. It seems to need a lot of attention and, the way it is positioned at the stern, does not make the boat very maneuverable. Tight turns to port are impossible unless one swivels the motor as well as the tiller. Docking in currents or cross-winds can be a heart-stopping experience. So I am thinking of installing an inboard engine, preferably electric. Has any one done such a thing, or does anyone have advice on what to do and what not to? I am thinking of doing most of the work myself, perhaps with some help of marina staff.
Many thanks.
garinel

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Offline moonlight

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Re: Conversion to inboard electric propulsion
« Reply #1 on: February 28, 2013, 06:30:18 PM »
On a commercial side, and not a plug, but I've been recommending such systems to similar sized boats for years.  Happy to report none sold yet, although in the past two weeks I have become involved in negotiations with one of the market leaders regarding a dealership or distributorship for same.
But none of that answers your questions, and I want to steer clear of commerical plugging.  If you need me offline, contact me off line.
On an experiential note, if you can do all your maneuvering with under 2 hours of mechanical assistance, you can hit a home run.  Outside of that, you'll need some way to recharge. 
In my experience, 98% of sailors can do this; after all, they're sailboats!  On and off the dock, set the sails...
Good luck and please keep us all informed!

Offline Salty19

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Re: Conversion to inboard electric propulsion
« Reply #2 on: February 28, 2013, 10:33:59 PM »
Well, this probably isn't a informed answer, so take it for what it's worth.

Wouldn't the outboard, with it's adjustable direction propulsion, be MORE maneuverable than a fixed prop?
Now I've never had an inboard boat, so I'm not too familiar with they have maneuver differently from the outboard in real-life operation, but from what I've read they are more difficult, in general, and of course more difficult to unfowl should weeds or fishing line get wrapped around the shaft. It probably depends on the rudder distance, shape, orientation of the prop, etc too.

Having also docked in some hair-raising wind, I was glad to have the outboard for better directional control, especially those last few, slow speed, seconds before jumping on the dock.

With that said, the idea of an electric sailboat is appealing for many reasons.  For those facing the cost of a new motor, are tired of ethanol issues, etc it's something to consider.

Offline skip1930

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Re: Conversion to inboard electric propulsion
« Reply #3 on: February 28, 2013, 11:06:37 PM »
O.K. Let us look at the parts first.

~Starting with a hollow thin fiberglass bilge meant to collect water there is no 'dead wood' a shaft can protrude out of and into the water.
~How much kw [hp] is needed?
~Needed will be a mount for a round electric footed motor. This mount should be part of the hull structure capable of absorbing the kw [hp] of the motor.
~Where to place the motor and keep it there? No through the hull fasteners in the bilge. Or factory fiberglassed in timber.
~So fiberglass in the mount after the mount is designed and fabricated.
~Electric motors are heavy being ladden with iron and copper. Baldor Motors are the best. Last for ever and weight 25% more then a Lincoln. That aside.
~Electric motors develop full torque at anything above zero rpm. And develop full load amps, [current]. That's a bunch of amps to start a motor at 12 v dc.
~The push from the propeller is going to going to move water equal to the weight of the boat's displacement in order for the boat to go forward.
~Prop push is transmitted up the shaft, through a water resistant Cutler Bearing, to a flexible coupler at the motor.
~How much does the boat weigh? Gallons moved?
~There is no good way to support the Cutler Bearing without solid 'deadwood'. Vibration will be a problem, leaks will follow. Motor will shake.
~May want to mix up 25 gallons of resign and pore that into the bilge for deadwood and drill that out for a shaft alley and Cutler Bearing. What's that weigh?
~This extra weight adds to displacement which adds strain upon everything, all the way up to the rigging.
~Now add the battery, the wiring, the controls, fuses or circuit breakers, a battery charger on board. More weight.
~What weight is astern is duplicated up forward for balance.
~I'm guessing the loss of one inch at the waterline if it can stay level.
~The prop. A three bladed affair. A two blade would be too large in dia. Folding props aren't that efficient, slip is a problem as is going astern.
~There is a formula for the distance from the back of the prop to the front of the rudder. A balanced rudder would complicate and reduce this distance.
~Corrosion just from moisture will be a problem with out a TEFCBB motor and moisture resistant switch gear.

I don't see it happening unless the stern of the keel is sawed off and redone. And that is just for starters. The vessel is only 25 foot long. It may be best to hang an electric trolling motor in place of the 9.9 Honda 4 stroke engine. [Never though too much of Honda auxilery engines]. The problem is their are no 10 hp electric trolling motors. Then extend the controls up and forward so the driver can better reach. Your still going to experience a turning problem based on just a tiller input. You'll have to turn the motor. And that brings up one more thing. With a non-directional prop in the skeg the rudder is all that will turn the boat. Back to square one.

I have found gunning my 5hp and turning the O/B and the tiller together, I can pretty much turn my CP-19 in her own length. My biggest problem is slowing or stopping the boat when approaching the dock. I come to a complete stop, drift, and drop her in gear for a shot and then back to natural...kind of on-off it up to the dock, drifting in, real slow.

skip.
« Last Edit: February 28, 2013, 11:20:30 PM by skip1930 »

Offline MacGyver

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Re: Conversion to inboard electric propulsion
« Reply #4 on: February 28, 2013, 11:45:48 PM »
First, this is a decent informed answer as far as I think, just because of the stuff I have dealt with over the years and a couple motor swaps I have been a part of.

If I were to do this kind of a mod on a compac with its keel style like it is I would go the way of the Menger Cat boats.
What skip is saying is way overkill........ Sorry Skip.

You would use a small shaft, length obviously determined by the available space. The place to set the engine up would be in the bilge, exiting out the rear with a fiberglass tube, faired into the hull and keel to allow the space needed.
By placing it directly in front of the rudder, you will get better performance due to its ability to push water across the rudder for decent steerage.

ISSUES: Reverse is a real pain in the A$$. but companies do offer adjustable props so that you can offset some forward for some reverse, or that they change into another position that better facilitates reverse.

Materials to do the whole job would be low, primarily depending on its placement...... the engine size can vary roughly last I had seen them, and one needs to have 2 batteries to support just that engine because at any time the possibility of blowing out a sail needs to be thought of. Great thing that sailboats have 2 engines in a sense....

To do the tube, and that area, you are looking at a packing gland, cutlass bearing (of which gets glassed into the tube), shaft, prop, and the motor, then it all has to be wired accordingly.
To do the epoxy work, I would say about 2 gallons if using West System epoxy, Plenty of Fiberglass tape, and something on the order of 10 X 40 grit discs and probably 15 X 80 grit discs. Gallon to gallon and a half of Interlux 2000 to seal the works up from the water and bottom paint of choice.
I would guess one might have somewhere in the order of 30 to 40 hours in construction and more for design once parts were chosen.

The other way is to come out of the hull somewhere and exit at a angle to the rudder, which would require a Fiberglass tube, connected to the packing gland, the shaft exits going to a custom rudder skeg which houses the cutlass bearing.
Even more work than what I first talked of.....

A costly venture for sure...... and I am not real sure for me, after being around boats for this long, that it is worth the conversion for such small gains, but possibly even bigger losses......

I do like the outboards, for their ability to turn and aid the rudder control.

And actually, this begs to ask, what is the rudder on your boat? Foiled or just the aluminum plate?   Maybe your in need of better steering control to aid in a more responsive boat to use in conjunction with the 25's hull, as I am sure windage is a issue when docking (hell, it is for me on the 19, and although we did really well last year ((only 2 X 1 foot long marks on the boat side)) I still know I could do better)

Anyway, It is totally doable, but If I were you, talk to some gusy with Catalina 30s and that sort of boat, the shaft and such is usually linear on them, they would be able to describe what it is like docking and such........

Still begs the question, what rudder do you have?

Mac
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Offline skip1930

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Re: Conversion to inboard electric propulsion
« Reply #5 on: March 01, 2013, 12:00:13 AM »
I'm thinking about how short the bilge is on these Com-Pacs. And narrow. [Don't be sorry, overkill? Use the K.I.S.S. method. Thanks].

You can't fit cardboard six pac in that hole on a CP-19 [I don't know about a 25] in a straight line between the back curve of the keel and the bulkhead/form used when the cement was poured into the keel. That bulkhead is there to hold the cement forward for weight distribution as it turned into concrete. At an angle you can skinny in a six pac and ice right over the bilge pump.

I'd be hard pressed to place an electric MOTOR [not engine] horizontal plus a tube, plus a bearing, plus a coupler.

Hey! How about a 90 degree reduction/reducer angle drive right out of W.W. Grainger and stand the motor on it's nose? That would be short. The motor would come up through the bottom of the potty on a CP-19 [again I don't know about a 25]. That's a bad thing. But the tube would come out the back end into the water and that's a good thing.

As to O/B and rudder cooordinated in Small Craft Adviser years ago I saw an O/B coupled to the rudder's head. They turn together. Don't remember if the O/B could be pulled up for less drag.

It's never easy.  Hydraulic drive is an idea...skip.

When I bought my CP-19, the boat next to it had a factory diesel in it. I think it was a CP-23 but may have been a CP-25. Nope. It was a 23.
« Last Edit: March 01, 2013, 08:44:45 AM by skip1930 »

Offline MacGyver

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Re: Conversion to inboard electric propulsion
« Reply #6 on: March 01, 2013, 12:06:35 AM »
Some of the motors I have seen were pretty short, but not sure on HP ratings versus size.

You are right though, a 90 degree nosed jobber would be pretty cool, or one where it was geared like a transfer case (which I have seen on a hydraulic driven boat..... Bayfield??)  which would allow that tight space.....

Lots to think about, and depending on space could be easy or a real Bit.........

Mac
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Offline Bob23

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Re: Conversion to inboard electric propulsion
« Reply #7 on: March 01, 2013, 04:56:26 AM »
Hi Gar and welcome!
   Interesting question and I have no experience with inboards of any type but I wonder what's wrong with your Honda? I've heard nothing but good about them. Maybe it can just be fixed- they have an excellent reputation for reliability. Someone on this forum a while back came up with a linkage kind of thing to enable turning the outboard as well as the rudder with the tiller. It's something I'd like for my 23 as I have occasionally kissed the rudder with my prop.
   Not many 25's around and I've often wondered about 'em. Seems like you have the best of both worlds- trailer ability and standing headroom. Hey- you're not the 25 at Mariners Marina in Barnegat, are you? I also sail Barnegat Bay in my 1985 23/2 "Koinonia".  I home port in Surf City.
Stay tuned for the famous up-coming Barnegat Bay Bash 2013!
   And, again- welcome!
Bob23

Offline Craig

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Re: Conversion to inboard electric propulsion
« Reply #8 on: March 01, 2013, 08:47:21 AM »
Welcome to the forum Gar. All of the above being said, go to: www.powertiller.com and take a look at their outboard steering system. It links your tiller to the OB via a simple and easily installed/ disconnected system of lines and blocks. Had both it and the powertiller motor control system on my Suncat. Works like a charm! You can check out the product demo videos on their site. I recommend both products highly! I did not even have to drill any holes in the Suncat. Just fastened the turning blocks to the boom gallows with stainless hose clamps. Having the motor controls: shift and throttle on the tiller is a real joy when docking and adding motor steering makes it really simple to maneuver. ;D
« Last Edit: March 01, 2013, 01:15:25 PM by Craig »
Craig, Horizon Cat "Kailani"  Punta Gorda, FL

Offline MacGyver

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Re: Conversion to inboard electric propulsion
« Reply #9 on: March 01, 2013, 09:29:31 AM »
Garinel,
I got to work to check what outboards we have the most trouble with and that happens to be the Honda 9.9 size range.
Turns out it is a jet size problem and corrosion.
Atleast that is our issues here where I am (fresh water lake in southern Illinois)

The fix seems to have been running Stabil (Blue in color) and a fuel enzyme (I will get the name for ya) and that seems to help with the issues essentially caused by the addition of ethanol into the marine world.
Honda is a fantastic engine.....but picky as heck at times.

A customer here told me last year he changes his spark plug 2 times a year (beginning and mid year) and that fuel recipe and he is running a lot better.

Maybe that will help you if she is running unreliably for you

Mac
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Offline Greene

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Re: Conversion to inboard electric propulsion
« Reply #10 on: March 01, 2013, 09:58:08 AM »
I liked The simplicity in this tiller to outboard linkage thread by Kchunk.

http://cpyoa.geekworkshosting.com/forum/index.php?topic=2808.0

Mike
« Last Edit: March 01, 2013, 10:00:22 AM by Greene »
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Offline NateD

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Re: Conversion to inboard electric propulsion
« Reply #11 on: March 01, 2013, 02:23:52 PM »
In the slip next to be is a CP25 with wheel instead of tiller and the rudder is hung on a post. Out of curiosity, is the rudder transom hung for the tiller model, or does the rudder extend so far back that it hits the outboard when it is in the water?

There was a good article on converting from an Atomic 4 inboard to electric in the May/June 2011 (Edition 78) of Good Old Boat magazine. You'll have a few extra steps, but that would give you some idea of the real work challenges involved.

Offline moonlight

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Re: Conversion to inboard electric propulsion
« Reply #12 on: March 01, 2013, 07:04:15 PM »
Having owned two CP 25's, I certainly can't speak for all of them, but maybe most.  At least 2 percent by production numbers I imagine.

The hull form already has a slot and a shape for a prop shaft as the vessel is/was offered with inboard Westerbeke 12CTwo's.  I can't say for sure but I can't imagine they had two hull molds, so I bet every one has this shape.

Both of mine had the inboards, and wheel steering.  I'm sure there is no modification to the rudder post, and it is hung in a sleeve 12~18" ahead of the transom; it is a foiled rudder.

The inboards had motor beds glassed in; they may have eliminated that step in ones built for outboards but that's probably a 50/50 shot in the dark.  Would not be hard to add in either case.

Realize guys the lazarette on the 25 has room for a hot water heater (6 gal), 8 gal fuel tank, inboard diesel and clutch, two batteries, and still room to get in and stand. 

Baldor versus Lincoln is a nice discussion, but irrelevant here.  these are not AC motors.  I just reviewed a 14kW 72V electric install and here's a picture of the motor part; maybe maybe at best it was a 16" x 4" pancake. 

That propulsion system inclusive of batteries and cabling I think ran about $15k.  Money, sure!  Lots of it, not really.  And since a CP 25 can get away with probably 3~5 kW, it's probably half that cost.  (But it won't go much lower than that).  Heck, WestMarine has them online under $5k!  I wouldn't go that way unless you really know what you're doing; because their support isn't what it could be, but it's a jumping off place.

So really, this is a VERY realistic option.  Enough room for beaucoup batteries and a decent charger, more than enough room for the motor and shaft (this would fit in the space of the existing inboard clutch assembly only!).

The 25 is not the 23, but even the 23 could have a diesel.  And the 23 is no 19, that's for sure!

Offline garinel

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Re: Conversion to inboard electric propulsion
« Reply #13 on: March 02, 2013, 01:33:17 PM »
My goodness, you guys are terrific!  Many thanks for the warm welcome and the many suggestions - for sure more advice than I can possibly take in all at once.

To answer some of your questions: Moonlight is right, there is plenty of space in the lazarette for an inboard engine, and the hull is already shaped in such a way that it is clear where the propeller shaft is to go through it. But, and this is a problem Skip pointed out, there is no motor bed glassed to the hull on the inside. They left that step out. Reading your comments, it seems to me that unless one knows exactly what one is doing, one can really screw up royally, and perhaps ruin a perfectly fine boat. But I haven't given up yet...

To answer some of your questions:
I am sailing out of Toms River at the moment. I have seen one CP27 down there but did not know there was another CP25 on the bay. They are great boats and not very hard to trailer at all, despite their substantial weight (some 5000+ lbs).

As to the O/B: My Honda is bolted to a metal bracket, so at the moment it can only swivel if one unscrews that bolt. And then you have to push it over by hand. The previous owner had installed some flimsy system by which the motor rotated somewhat with the rudder, but I did not like it and thought I could manage without it. I can, sort of. But as I said, having the O/B fixed behind the rudder and to the side provides me and my crew with some unwanted extra excitement from time to time. I'll look into the linkage systems some of you suggested me to - many thanks for that.

For the last two seasons, I had endless issues with it overheating and generally not running reliably (e.g. stalling preferably when one goes into reverse when approach a dock :-[ ) All happened before and after an expensive service.
Adding Stabil did not do the trick (thanks McGyver for that suggestion; but I don't know that I understand what you mean by "jet size problem").
In any case, by the end of last year's season, just before Sandy hit, I *may* have figured out how to get the motor running smoothly: 1) always use fresh fuel, highest grade; 2) and perhaps more importantly, flush engine not just with fresh water but with fresh water AND CRC Salt Terminator (or similar product). But that takes 30mins or so to run through. I want to *sail* and not spend my spare time pampering the O/B, and then still worry about what it will do next.  Hence the idea of throwing the O/B overboard and go electric.

Cheers,
garinel

-garinel

Offline moonlight

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Re: Conversion to inboard electric propulsion
« Reply #14 on: March 02, 2013, 02:56:53 PM »
Find a good fiberglass shop this winter and they can easily put some beds in there for you.  Heck, there's enough room (without fuel tank or water heater) for the guy to take a nap while the resin cures.

Consider mapping it all very well and having bolts glassed in, as well as using foam core board instead of wood.  Material cost is 30% more but it's insignificant on the scope of your project ($40 of material versus $30, or even $400 versus $300, no matter) and the foam will never ever ever never rot or get spongy.  If you set anchors now, even concrete J-bolts, you can always use them to anchor a sacrificial board later to bolt to.

Most motor mounts are lag bolted into the stringers/beds.  This sucks, because the first a-hole to overtighten the lag bolt destroys the hole.  And from that point on you're left filling and fixing and it's never as nice as a new properly bedded one. 

Another option is building the beds high enough to hole saw through them allowing through-bolting.

While you're in there, have him install a dormitory size fridge just behind the companionway stairs; add some extra batteries and you've got 12V refrigeration without messing with the stock icebox.

IF you want to extend cruising range, there's always room in there for a small genset ahead of the electric motor and then you're hybrid instead of pure electric, but you'll have a way to regenerate underway (better than prop spinning which works but very slowly).