Electric propulsion

[Bob Bois]

This has been discussed on several other forums. We are interested in electric propulsion for our Tiki 46 and have been in touch with several builders who have installed e-pods, etc. However, does anyone currently using electric motors for propulsion have a report on the practicality of the current products?
There's been alot of discussion regarding the weight of the batteries as a limiting factor, the best (and worst) power regeneration methods, the best (and worst) products currently available.
I don't want to summarize it all here, but I would like to open the discussion and see if there is any further interest within this really knowledgeable community in brainstorming how this might (or might not) be worthwhile (and cost-efficient). I'd be interested in any aspect of electric propulsion anyone might want to discuss, from recharging batteries to the best placement of electric motors and the pros and cons of the overall concept. I received an email from some builders who are using e-pods with their Pahi 63 and say they are really pleased with it. Ther

[Bob Bois]

I should add, we do realize we are building a SAILboat. I ask about electric motors only from the standpoint of auxiliiary power. We don't expect to be motoring around all the time...just thought I'd clarify that!

[Ann and Neville Clement]

Hi,
Jeff Kittle installed electric propulsion on his Tiki 46, Kittywake, using fixed props one per hull and is totally disappointed with the results. Dearly wishes he had outboards and is actually using one outboard now to move the boat. I will phone him tonite and ask him to come on to this web. His thought is that the idea is great but it is not fully developed yet. Maybe by the time you are ready, though, Bob. Or perhaps with a different installation...? I am sure Jeff will have more thoughts to share. Ann and Nev

[Bob Bois]

We have already ruled out fixed props as we saw what even a small outboard left deployed did to our Tiki 30's headway and tacking. If we went with electric, we'd still want to raise the pods out of the water via the engine boxes when sailing. Easier to repair too....

[Bob Bois]

Thanks Greg. I've looked at Torqueedo and at least they are putting something out that makes some sense, even if not ideal. I don't mind anyone running down elec propulsion but I'm hoping we can keep this discussion focused on the technology and its practical applications (or not) and out of personal animosity. I actually would love to see us airing all arguments for and against this technology. We should all remember that the part of the established opinion in the 1950's was that catamarans could not safely make ocean passages.... who knows what this technology will look like in the next decade? Personally, I would rather increase my seamanship skills and my life situation to the point where auxiliary power was not an active consideration. In the meantime....

[Ann and Neville Clement]

I sure hope you can get this technonogy up and running soon. It sounds so interesting. But one thing about the Tiki 46 that I feel some concern about is manouvering in crowded anchorages and harbors. Nev and I usually avoid them, but sometimes we do need to get Peace into one during cross wind conditions or wind against tide. We have the two Yamaha 9.9 outboards as per the design. You would want at least that amount of power and at least that amount of being able to turn the boat. Admittedly we are not super skillful though. Nev wants to move up to 15 horse outboards. I do agree that having the electrics in lifting pods would make them a lot more attractive. I did ask Jeff to come on this site. Ann and Nev

[Bob Bois]

Thanks Greg, and Ann and Nev,
There is no doubt that manouvering a Tiki 46 in tight situations requires power. Greg, I don't have the numbers right now, but as Ann stated, the designers recommend dual 9.9 hp outboards.
The placement of the engine boxes leaves the outboards between the hulls, thus decreasing manouvering ability. I've been tinkering with the drawings for a linkage that would allow one to lower, say, a pair of e-pods (of sufficient power) and deploy them between the aft end of the keel and the skeg. Trying to get the benefit of the placement of fixed props while also being able to raise them. This is all predicated on the arrival of products (within budget) on the market in the next 5 years or so. I'm continually researching the industry to see where they are. All that said - we are currently planning on using the outboards per the design unless something else practical comes into being. I hope we hear from others with an interest in this subject also..

[Bertrand FERCOT]

The Reepower electric engines aren't enough powerful for the Tiki46, so the Torquedos. Our Belgium friends installed one 10kw electric brushless Bellman pod in each hull of their Tiki46 Apatiki. It's a minimum to get a good maneuverability in strong winds. You can have a look at their website :
http://tiki46-2009.skynetblogs.be/archive-month/2009-01
As each pod is in front of each skeg, it's very efficient to turn. The weakness is it's a serial hybrid system with about 30 minutes of use at full power or a few hours at low powerful on a flat sea. If the diesel generator has a failure or the electronic driving the engine is out you're not very relaxed (I prefer the brush electric engines which can run without electronic in emergency mode).

Personally I prefer to have the electric engine in the hull for easier maintenance and for offshore cruises I prefer a parallel hybrid system with a classical diesel engine running the propeller + just after the gear box in parallel an electric engine abble to move the boat for the arriving and departure of moorings and to regenerate the batteries under sails. With a such hybrid system in each hull you have a very good reliability, I think to use only the electric engines 80% of the time when motoring, using the diesel engines only to enter in a shelter against strong winds or currents or to motor a long time in high pressure areas.
Sorry, now I've to sleep, I'll tell you more about my own choice later.

Bertrand

[Ann and Neville Clement]

I am understanding that you intend to make lifting props which will locate just aft of the keels when down? That sounds like a wonderful idea to me. If you can get the props farther apart than we have on Peace, then you would turn easier. Right there you might get some prop wash on the rudders too.

Just another idea... When we were discussing building Peace with Wharrams back in the mid 90s, the early plan was to locate the outboards forward of the pod in the area were the design now has seats. For some reason the design changed to locate the outboards in the aft cockpit and I do not remember why that changed. But maybe the boat would turn easier if the props were closer to the central location? Certainly there would be less trouble with cavitation in that location. Saying that though, Peace has very little trouble with cavitation as it is. I do think that having two props would be the best plan so one could go ahead and the other astern when turning. You could locate the engine in front of the pod?

We are not ever eager to lift the mattresses from the aft cabins to get at the storage there where you guys are thinking of installing engines. That area is not easy for me to get into. Admittedly I am old and stout, but reaching stuff there is not easy even for Nev. A good location for a large lump of engine might be in the aft cockpit where Peace now sports a freezer inside an insullated box. This is not in the way at all, is easy to get at, and makes a good place to serve supper on warm evenings so is easy to live with. It is actually a good place to sit to keep watch.

Ann and Nev

[Budget Boater]

Bertrand FERCOT said:

The Reepower electric engines aren't enough powerful for the Tiki46, so the Torquedos. Our Belgium friends installed one 10kw electric brushless Bellman pod in each hull of their Tiki46 Apatiki. It's a minimum to get a good maneuverability in strong winds. You can have a look at their website :
http://tiki46-2009.skynetblogs.be/archive-month/2009-01 As each pod is in front of each skeg, it's very efficient to turn. The weakness is it's a serial hybrid system with about 30 minutes of use at full power or a few hours at low powerful on a flat sea. If the diesel generator has a failure or the electronic driving the engine is out you're not very relaxed (I prefer the brush electric engines which can run without electronic in emergency mode).
Personally I prefer to have the electric engine in the hull for easier maintenance and for offshore cruises I prefer a parallel hybrid system with a classical diesel engine running the propeller + just after the gear box in parallel an electric engine abble to move the boat for the arriving and departure of moorings and to regenerate the batteries under sails. With a such hybrid system in each hull you have a very good reliability, I think to use only the electric engines 80% of the time when motoring, using the diesel engines only to enter in a shelter against strong winds or currents or to motor a long time in high pressure areas.
Sorry, now I've to sleep, I'll tell you more about my own choice later.

Bertrand

First, I cannot believe you guys started this topic while I was on vacation and could not participate. Electrical is by far my favorite part of boats.

Bertrand,

Before making any comments about this, it is important to know exactly what what installed and how. I have dealt with marine electrical and propulsion systems for quite some time and have found that improper installation is almost always the cause of poor performance in an electric drive.

Which system was installed? Was it the 2000 or 3000 and was it dual drive or single?
How many batteries and what type and size were used?
What voltage was the system set up for - 36 or 48V?
Were there separate banks for each drive if two were used?
What size battery cables were used and how far were the runs one way?
Was the drive(s) installed in the hull or on skegs of some kind?
What was the pitch of the props?
Did they have the generator?
How were the batteries maintained and charged?

I am not requesting that you answer these questions, just pointing out how many potential places there are for a system to be improperly installed, used, and/or maintained. Being deficient in just one single area will cause the entire system to not preform properly. A properly designed and installed hybrid diesel-electric propulsion system will easily out perform outboards any day, with the exception of weight. A hybrid diesel-electric system also provides triple redundancy for the entire boat's electrical and propulsion systems, which outboards simply cannot do.

All this being said, for boats as large as the Tiki 46 and larger, it would be a better choice to go with twin diesel inboards. The cost is about the same as a properly configured hybrid system and also weighs less.

[Björn]

I would suggest a hybrid if there are double engines:
one 9,9 Yamaha and one of of the strongest Torqeedos (Cruise 4.0R). This gives the manouverability of two engines and the short distance running with one engine only. For long distances I would then use the 9,9 Yamaha. When doing long distances on my Tiki 38 I am using only one engine anyway.

If the Torqeedo would have been around about three or four years ago I would have installed this configuration (only after careful real evaluation on thewater) , weight wise it would be pretty neutral to two 9,9ers. The advantage would be that you do not need a generator ..... and you also have two independent systems.

I am using a small Torqeedo Travel 800 for the dinghy, (since I have it the petrol engine (Yamaha Malta) went onto the cellar and has not been used), it does not go as fast but is sufficient fo raht you do with a dinghy. The battery is typacilly charged with the dolar panels from the boat.

In summary, I recommend the guys who have commented so far, getting one of the Torqeedos on loan froma dealer and try it out and share the experiences (not talk about the whens and if like the theoretical physicist :-)).

[Bob Bois]

We had looked at the ST1 "wheel drive" from Solomon. These are the electric drives they're putting in the Lagoons right off the line. While under sail in good wind, the batteries can be re-charged via the 'wind-milling' props. However, I can't believe that this wouldn't just create so much drag that there wouldn't be much 'wind-milling' going on at all. In addition, this is a fixed drive and we definitely want a set up in which we can hoist up the props and not have any fixed hardware to cause drag. I have followed Bertrand's posts on several forums for many years and really admire his clear-eyed ingenuity. However, like Ann noted earlier, to install engines in the hull would make it difficult to work on them (for me, anyway - I'm not as tall as Bertrand but I am much...wider).
We want some auxiliary power for those times when the requirements of the situation exceed our sailing abilities (and we hope to reduce the frequency of these situations over time) but if and when in cruising mode, we won't sweat a time table and if there is no wind , so be it.
All that said, the ideal system would be a set up that is electric, can be re-powered through wind/solar (if not used often and for long distances), can deploy the props in front of the skegs (for manouverability), does not require a diesel gen to be practical, motors (and props) can be hoisted clear of the water for drag free sailing and for easy maintenance, doesn't require hundreds of pounds of expensive batteries, and is reasonably reliable.
There are other 'nice to have's' we can think of but these would be the major considerations. Can this system be put together? I realize it's idealistic but first we need to envision it, then perhaps investigate if it can be designed. Shane, what do you think? How close can we get to this system? If Lagoon is going electric (in its way), then the technology is maturing to the point where in the next few years we should see some (at least modest) advances, no?

[Budget Boater]

Here are my thoughts on this subject.

First, 9.9hp outboards are way to small for a T46 regardless of what Wharram thinks. These should be a pair of 20-25 hp outboards. This changes a person's perspective when cost and weight of the larger engines are brought into play.

Solomon has the best technology for what you what to do. However, 144V can be dangerous and deadly if you do not know what you are doing. One jolt will kill anyone deader than a hammer, and Solomon seems to downplay this risk. The battery weight is considerable at 720 lbs per bank using group 27 batteries. Without the generator, you need to be a sailing purist. I think Solomon thinks too highly of their product based on the exorbitant price they ask.

With any electric drive system, you have to balance your needs with the real world use. Based on my 12 years of living on and cruising on sailboats, I can say that I am not, nor will I ever be a sailing purist. I use the intracoastal waterway which requires long engine run times, I tend to motorsail when the wind gets too light, and I have had many occasions to push hard against a current when coming into or leaving a port. These things alone dictate that I install a generator for an electric drive system.

If you want to get longer "motoring" times without running or having a generator, then you must increase your battery bank size. Batteries are expensive and quite heavy - both seem to go against the grain of owning a Wharram Catamaran. For the best balance in the situation you have described here are my suggestions:

Re-e-power 3000 cat package installed on custom lifting foil skegs (or get a pair of the outboard models to install on the outboard legs per the design). Add the new nozzle to each for added thrust. Install individual 200 AH, 48V (4 Rolls T-12-250 batteries in series, with a weight 560± lbs per bank) battery banks for each pod. This should give you 1-5 hours of cruising run time per charge, depending on conditions, without a generator and still maintain good battery regime.

Please note: without significant down time or shore power charging between heavy uses, there is no way keep the batteries properly charged without a generator. If you plan to cruise, and anchor out most of the time, you will most likely need to get the generator. Premature battery failure is almost always attributed to one thing - chronic battery undercharging.

Here is why this is the case and assumes for this example that you depleted both battery banks by 50% (200 AHs total): Solar charging example - 4 100W solar panels in series for 48V will produce about 8 amps per hour (at 48V) in direct sunlight. In typical Florida/Bahamas weather, you can expect to get 44 amp hours per day average. This must be reduced by 20% to account for charging inefficiencies, so the actual charge to the batteries per day would be 35 AH. At this rate, it would take you 6 days to properly recharge your batteries from this solar array if no other loads were drawn during the charge phase. Double the array (about the max that could fit on the T46 and not make it look weird) and you could do it in 3 days.

From this, you have to decide what is right for you. No matter how you slice it, an electric drive system (hybrid or not) will cost and weigh more than gas outboards. You have to figure out what you want to do.

I am an electric drive kind of guy, but at some point the cost benefit analysis gets out of proportion. I think this happens at the range of the T38 and T46. Properly installed diesel inboards can be very light, easy to maintain, and extremely long lasting. There are wonderful automatic oil change systems for diesels now. Simply push a button and the oil comes out. Spin on a new filter and poor in new oil and you're done. There is really nothing else to maintain on a diesel. Properly locating the raw water inlet and strainer will keep you from having to work your way into a small space.

In the end, you just have to think the entire system through from beginning to end. Weigh the pros and cons, and put it all down on paper. Eventually, a good picture will emerge and you can make a decision.